New trials for NRAS and Mucosal Melanoma patients - ASCO 2021

Melanoma sucks great big green hairy stinky wizard balls for everyone!  Still, it remains even more challenging for NRAS positive and mucosal melanoma patients.  Here are prior posts on Mucosal Melanoma. Now, there's this neoadjuvant trial:

A phase 2 clinical trial of neoadjuvant anti-PD-1 ab (toripalimab) plus axitinib in resectable mucosal melanoma.  Cui, Wang, Lian, et al.  ASCO 2021.

Background:  The outcome of patients (pts) with resectable mucosal melanoma (MM) is still poor. Toripalimab combined with axitinib has shown impressive results in metastatic MM with an ORR of 48.3% and a median PFS of 7.5 months in a phase 1b trial. It was hypothesized that this combination therapy might cause pathologic response in neoadjuvant setting for resectable MM, so we conducted this single arm phase 2 trial.

Methods:  Eligible pts were adults (aged 18 to 75) with histologically confirmed resectable (localized or regional lymph node metastasis) MM disease. Exclusion criteria included ocular or unknown primary melanoma, distant metastatic disease or previous use of anti PD-1 ab. Pts received toripalimab 3 mg/kg Q2W plus axitinib 5 mg BID for 8 weeks as neoadjuvant therapy, then surgery and the adjuvant toripalimab 3 mg/kg Q2W starting 2±1week after surgery for totally 52 weeks. The primary end point is pathologic response rate according to the International Neoadjuvant Melanoma Consortium (pCR+pPR, pCR is defined as the complete absence of residual viable tumor and pPR less than/= to 50% of viable tumor cells). The secondary end point is RFS in the ITT population.

Results:  From Aug 2019 to Dec 2020, 21 pts have been eligible and enrolled. Basic characteristics: median age 62 years; M: F 28.6% : 71.4%; primary sites 8 female genital(1urethra, 7vagina), 5 esophagus, 4 ano-rectal, 4 head and neck(3 nasal,1 oral), in which 47.6% localized disease (T3/4 60%), 52.4% regional lymphatic disease; Gene mutation: 4 cKit (1 amplification), 2 Nras,1 Braf (N581), 1mTOR. This therapy was tolerable with grade 3-4 treatment related AEs of 23.8% (liver dysfunction 14.3%, hyperglycemia 9.5% and hypertension 4.8%). 13 pts had received surgeries (local excision 30.8%, wide excision ± CLND72.7%)and 5 pts still in neoadjuvant treatment. One patient was inoperable for bone metastasis, and 2 pts withdrew for covid 19 epidemic. At a median follow up time of 59 weeks, the pathologic response rate was 28.6% (4/14, 2 pCR, 2pPR). Of the post-surgical specimens, 61.5% (8/13) showed significant TIL infiltration, with 38.5% Brisk and 23.1% Nonbrisk according to the definition of AJCC 8th edition. Plenty of plasma cells, histiocyte and pigment with hyaline fibrosis were also found in responders. No recurrence or metastasis was observed in responders until now, with a RFS reaching more than 58weeks. 5 pts with pNR (greater than 50% viable tumor cells) got disease progression, with 1 local recurrence, 1 regional lymphatic metastasis, and 3 distant metastases. The median RFS has not been reached.

Conclusions:  Neoadjuvant toripalimab plus axitinib in resectable MM has shown promising pathologic responses with good tolerance, which supports further investigation of neoadjuvant therapies in MM. Survival is still in follow-up. Clinical trial information: NCT04180995.

And this report on patients with unresectable disease:

Atezolizumab in combination with bevacizumab in patients with unresectable locally advanced or metastatic mucosal melanoma: Interim analysis of an open-label phase II trial.  Si, Fang, Chen, et al.  ASCO 2021.

Background:  Mucosal melanoma is a rare malignant melanoma in Caucasians but ranks the second most common subtype in the Asian population. It is more often diagnosed at an advanced stage and responds poorly to current PD-1/PD-L1 inhibitors. Here we report the interim analysis results of ML41186, an open-label, multicenter, single-arm phase II study, aiming to evaluate the efficacy and safety of atezolizumab in combination with bevacizumab in patients (pts) with advanced mucosal melanoma.

Methods:  Eligible pts aged 18 to 75 years with histologically confirmed unresectable locally advanced or metastatic mucosal melanoma had at least one measurable lesion per RECIST version 1.1 at baseline, with an ECOG PS 0 or 1 and adequate hematologic and organ function. ML41186 is a Simon two-stage design study, if 22 pts completed ORR evaluation and more than 3 pts respond in stage I, the study then continue to Stage II. Atezolizumab and bevacizumab were administered at a fixed dose of 1200 mg and 7.5 mg/kg Q3W respectively (on day 1 of each 21-day cycle) until unacceptable toxicity or loss of clinical benefit. The primary endpoint is the objective response rate (ORR). The secondary endpoints include progression-free survival (PFS), duration of objective response (DoR), disease control rate (DCR), and safety.

Results:  By the cut-off date of 9th September 2020, 35 pts has been enrolled, among whom 22 pts in the stage I analysis set has completed two efficacy evaluation, while 28 pts (full analysis set) has completed at least one efficacy evaluation. In ITT populations (n=35), mean age was 58.9 years with 10 (28%) pts had ECOG PS of 1. LDH level elevated in 9 (25.7%) pts. More than half pts (19, 54.3%) had metastatic mucosal melanoma, of whom 3 (15.8%) pts had more than 3 metastasis sites and 4 (21.1%) pts had liver metastasis. In stage I analysis set (n=22), the best confirmed ORR was 36.4% (17.0%-59.3%). Median progression-free survival was 5.32 months (1.58-not reached), and the best confirmed DCR was 59.1% (36.4%-79.3%). The median confirmed DoR was not reached ( 2.76-NR). In the full analysis set (n=28), the unconfirmed ORR was 42.9% (24.5%-62.8%). In ITT populations (n=35), 28 pts (80%) experienced at least one adverse event (AE) and 5 pts (14.3%) experienced at least one grade 3-4 AEs. Only one patient experienced AE leading to treatment discontinuation. One patient died of autoimmune lung disease.

Conclusions:  The combination of atezolizumab plus bevacizumab showed promising benefit and was tolerable in pts with advanced mucosal melanoma. At the time of this interim analysis, the primary endpoint did not cross the futility boundary, thus the study will run into Stage II. Clinical trial information: NCT04091217.

The NRAS mutation has it's own challenges.  Here are prior NRAS Reports.  Now, there are these:

A phase Ib trial of belvarafenib in combination with cobimetinib in patients with advanced solid tumors: Interim results of dose-escalation and patients with NRAS-mutant melanoma of dose-expansion. Shin, Lee, Kim, et al.  ASCO 2021.

Background:  Belvarafenib, a potent, selective RAF dimer (type II) inhibitor, exhibits clinical activity in BRAFV600E- and NRAS-mutant (NRASm) melanoma patients. The combination of belvarafenib and cobimetinib more potently and durably suppressed MAPK pathway output and tumor growth than currently approved BRAF/MEK inhibitors in RAS- or RAF-mutant tumor xenograft models. This interim results of phase 1b trial evaluated the safety, tolerability, pharmacokinetics, and anti-tumor activity of belvarafenib in combination with cobimetinib in dose-escalation and NRASm melanoma patients among the 9 indication-specific expansion cohorts.

Methods: Patients with locally advanced or metastatic solid tumors harboring RAS or RAF mutation were enrolled in the dose-escalation stage, and the recommended doses were explored in the indication-specific expansion stage. Patients in the dose-escalation stage were given belvarafenib (100–300mg BID) in combination with cobimetinib (20–40mg QD) and the dose of subsequent cohorts was decided by a traditional 3+3 design and safety profile. Primary objectives were to evaluate the safety and tolerability, to estimate the maximum tolerable dose, and to identify the RP2D of the combination.

Results:  A total of 32 patients enrolled were evaluated for safety analysis; 19 were enrolled in 4 cohorts in the dose-escalation stage and 13 NRASm melanoma patients were enrolled in the indication-specific expansion stage (cut-off date: 2020-7-24). There were 3 DLTs (G3 colitis, G3 diarrhoea, G3 nausea) in 2 patients at the starting dose of belvarafenib 200mg BID continuously and cobimetinib 40mg QD 21/7 schedule. Belvarafenib dose was escalated to 300mg BID with cobimetinib 20mg QD, which did not result in DLTs. The most common treatment-emergent adverse events that occurred in ≥30% of 32 patients were dermatitis acneiform, diarrhoea, constipation, and increase in blood creatine phosphokinase. Two combination doses were explored in the indication-specific expansion stage. Out of the 9 indication-specific expansion cohorts, NRASm melanoma patients exhibited promising efficacy signal; 5 patients reached partial responses (PRs) out of 13, giving a response rate of 38.5%. Among them, 11 had been previously treated with checkpoint inhibitors (CPIs), including 5 (45.5%) who achieved PR. The median PFS was 7.3 months and 5 patients remained on the treatment at the cut-off date.

Conclusions: Belvarafenib in combination with cobimetinib showed acceptable tolerability and encouraging efficacy in NRASm melanoma, and in those with prior CPI treatment. Further research is ongoing in other cohorts (Clinicaltrial.gov, NCT03284502) and in NRASm melanoma (reference GO42273 by clinicaltrials.gov ID number). Clinical trial information: NCT03284502.

Fingers crossed that there will soon be viable treatments for all melanoma ratties.  For what it's worth - c

Circulating tumor DNA to monitor and predict response in melanoma patients - yes - AGAIN!!!!

I first posted articles related to blood analysis to evaluate circulating tumor DNA in 2014.  It is a fairly non-invasive and relatively painless way to diagnose melanoma, measure tumor burden, and evaluate progression or response in melanoma patients.  It may even indicate those who are more likely to respond to a particular therapy.  Unfortunately, it is not commonly utilized.  Here are zillions of articles:  Circulating Tumor DNA for melanoma

Now, there are these:

The use of circulating cell-free tumor DNA in routine diagnostics of metastatic melanoma patients.  Knuever, Weiss, Persa, et al. Sci Rep. 2020 Mar 18.

Modern advances in technology such as next-generation sequencing and digital PCR make detection of minor circulating cell-free tumor DNA amounts in blood from cancer patients possible. Samples can be obtained minimal-invasively, tested for treatment-determining genetic alterations and are considered to reflect the genetic constitution of the whole tumor mass. Furthermore, tumor development can be determined by a time course of the quantified circulating cell-free tumor DNA. However, systematic studies which prove the clinical relevance of monitoring patients using liquid biopsies are still lacking. In this study, we collected 115 samples from 47 late stage melanoma patients over 1.5 years alongside therapy-associated clinical routine monitoring. Mutation status was confirmed by molecular analysis of primary tumor material. We can show that detectable levels of circulating cell-free tumor DNA correlate with clinical development over time. Increasing levels of circulating cell-free tumor DNA during melanoma treatment with either targeted therapy (BRAF/MEK inhibitors) or immunotherapy, during recovery time or the intervals between last treatment cycle and second-line treatment point towards clinical progression before the progression becomes obvious in imaging. Therefore, this is a further possibility to closely screen our patients for tumor progression during therapy, in therapy-free phases and in earlier stages before therapy initiation.

YEP!

Longitudinal monitoring of ctDNA in patients with melanoma and brain metastases treated with immune checkpoint inhibitors.  Lee, Menziew, Carlino, et al.  Clin Cancer Res.  2020 April 22.

PURPOSE: Brain involvement occurs in majority of patients with metastatic melanoma. The potential of circulating tumor DNA (ctDNA) for surveillance and monitoring systemic therapy response in patients with melanoma brain metastases merits investigation. 

EXPERIMENTAL DESIGN: This study examined circulating BRAF, NRAS and c-KIT mutations in melanoma patients with active brain metastases receiving PD-1 inhibitor-based therapy. Intracranial and extracranial disease volumes were measured using the sum of product of diameters, and response assessment performed using RECIST. Longitudinal plasma samples were analysed for ctDNA over the first 12 weeks of treatment (threshold 2.5 copies/ml plasma). 

RESULTS: Of a total of 72 patients; 13 patients had intracranial metastases only and 59 patients had concurrent intracranial and extracranial metastases. ctDNA detectability was 0% and 64%, respectively, and detectability was associated with extracranial disease volume. Undetectable ctDNA on-therapy was associated with extracranial response but not intracranial response. The median overall survival in patients with undetectable (n = 34) versus detectable (n = 38) ctDNA at baseline was 39.2 versus 10.6 months and on-therapy was 39.2 versus 9.2 months. 

CONCLUSIONS: ctDNA remains a strong prognostic biomarker in melanoma patients with brain metastases, especially in patients with concurrent extracranial disease. However, ctDNA was not able to detect or monitor intracranial disease activity, and we recommend against using ctDNA as a sole test during surveillance and therapeutic monitoring in patients with melanoma.

In this study of 72 patients, circulating tumor DNA was a useful biomarker in patients who had melanoma in both their body and brain.  The ability to monitor the status of patients with melanoma ONLY in their brain was not found.  It should be noted that this is one study and there were only 13 patients in the "brain met only" arm.

Circulating Tumor DNA Predicts Outcome from First-, but not Second-line Treatment and Identifies Melanoma Patients Who May Benefit from Combination Immunotherapy.   Marsavela, Lee, Calapre, et al.  Clin Cancer Res.  2020 Nov.

Purpose: We evaluated the predictive value of pretreatment ctDNA to inform therapeutic outcomes in patients with metastatic melanoma relative to type and line of treatment.

Experimental design: Plasma circulating tumor DNA (ctDNA) was quantified in 125 samples collected from 110 patients prior to commencing treatment with immune checkpoint inhibitors (ICIs), as first- (n = 32) or second-line (n = 27) regimens, or prior to commencing first-line BRAF/MEK inhibitor therapy (n = 66). An external validation cohort included 128 patients commencing ICI therapies in the first- (N = 77) or second-line (N = 51) settings.

Results: In the discovery cohort, low ctDNA (less than or equal to 20 copies/mL) prior to commencing therapy predicted longer progression-free survival (PFS) in patients treated with first-line ICIs, but not in the second-line setting. An independent cohort validated that ctDNA is predictive of PFS in the first-line setting, but not in the second-line ICI setting. Moreover, ctDNA prior to commencing ICI treatment was not predictive of PFS for patients pretreated with BRAF/MEK inhibitors in either the discovery or validation cohorts. Reduced PFS and overall survival were observed in patients with high ctDNA receiving anti-PD-1 monotherapy, relative to those treated with combination anti-CTLA-4/anti-PD-1 inhibitors.

Conclusions: Pretreatment ctDNA is a reliable indicator of patient outcome in the first-line ICI treatment setting, but not in the second-line ICI setting, especially in patients pretreated with BRAF/MEK inhibitors. Preliminary evidence indicated that treatment-naïve patients with high ctDNA may preferentially benefit from combined ICIs.

We already know that progression free survival and overall survival is better in those with the lowest tumor burden (no matter how you attain that information) and better in those who respond to treatment on the first go.  This study confirms that using ctDNA.  We don't fully understand why melanoma peeps respond less well on their second round of therapy and this report indicates that ctDNA is less useful in that setting as well - though they looked at small numbers here with 32 patients in the first line immunotherapy treatment cohort and only 27 peeps were using it for the second time.  There were 66 patients using targeted therapy for the first time.

Circulating tumour DNA and melanoma survival: A systematic literature review and meta-analysis.  Gandini, Zanna, De Angelis, et al.  Crit Rev Oncol Hematol.  2020 Nov.

We reviewed and meta-analysed the available evidence (until December 2019) about circulating tumour DNA (ctDNA) levels and melanoma patients survival. We included twenty-six studies (more than 2000 patients overall), which included mostly stage III-IV cutaneous melanoma patients and differed widely in terms of systemic therapy received and somatic mutations that were searched. Patients with detectable ctDNA before treatment had worse progression-free survival (PFS)  and overall survival (OS), with no difference by tumour stage. ctDNA detectability during follow-up was associated with poorer PFS and OS; in the latter case, the association was stronger for stage IV vs. III melanomas. Between-estimates heterogeneity was low for all pooled estimates. ctDNA is a strong prognostic biomarker for advanced-stage melanoma patients, robust across tumour (e.g. genomic profile) and patients (e.g. systemic therapy) characteristics.

Detectable ctDNA  before treatment correlated in a decreased progression free survival and overall survival for both Stage III and Stage IV peeps.  When ctDNA was detectable during follow-up after treatment, associated PFS and OS was worse, but the decreased OS was even more significant in Stage IV patients.

Circulating Tumour DNA in Advanced Melanoma Patients Ceasing PD1 Inhibition in the Absence of Disease Progression.  Warbutron, Calapre, Pereira, et al.  Cancers. 2020 Nov.

Immunotherapy is an important and established treatment option for patients with advanced melanoma. Initial anti-PD1 trials arbitrarily defined a two-year treatment duration, but a shorter treatment duration may be appropriate. In this study, we retrospectively assessed 70 patients who stopped anti-PD1 therapy in the absence of progressive disease (PD) to determine clinical outcomes. In our cohort, the median time on treatment was 11.8 months. Complete response was attained at time of anti-PD1 discontinuation in 61 (87%). After a median follow up of 34.2 months (range: 2-70.8) post discontinuation, 81% remained disease free. Using ddPCR, we determine the utility of circulating tumour DNA (ctDNA) to predict progressive disease after cessation (n = 38). There was a significant association between presence of ctDNA at cessation and disease progression and this conferred a negative and positive predictive value of 0.82 and 0.80, respectively. Additionally, dichotomised treatment-free survival in patients with or without ctDNA at cessation was significantly longer in the latter group. Overall, our study confirms that durable disease control can be achieved with cessation of therapy in the absence of disease progression and undetectable ctDNA at cessation was associated with longer treatment-free survival.

In this study, looking at melanoma patients who stopped immunotherapy after about a year, researchers found that disease progression was strongly associated with those who had detectable ctDNA when they stopped treatment.  Not a surprise.  SO - if you are thinking of stopping treatment due to side effects or a complete response per scans, getting ctDNA analyzed may be an important factor in that decision making process!

Stopping targeted therapy for complete responders in advanced BRAF mutant melanoma. Warbutron, Menjawy, Calapre, et al.  Sci Rep.  2020 Nov 2.

BRAF inhibitors revolutionised the management of melanoma patients and although resistance occurs, there is a subgroup of patients who maintain durable disease control. For those cases with durable complete response (CR) it is not clear whether it is safe to cease therapy. Here we identified 13 patients treated with BRAF +/- MEK inhibitors, who cease therapy after prolonged CR (median = 34 months, range 20-74). Recurrence was observed in 3/13 (23%) patients. In the remaining 10 patients with sustained CR off therapy, the median follow up after discontinuation was 19 months (range 8-36). We retrospectively measured ctDNA levels using droplet digital PCR (ddPCR) in longitudinal plasma samples. CtDNA levels were undetectable in 11/13 cases after cessation and remained undetectable in patients in CR (10/13). CtDNA eventually became detectable in 2/3 cases with disease recurrence, but remained undetectable in 1 patient with brain only progression. Our study suggests that consideration could be given to ceasing targeted therapy in the context of prolonged treatment, durable response and no evidence of residual disease as measured by ctDNA.

Same song, second verse in regard to two points here.  Folks going off targeted therapy did better if they had no detectable ctDNA.  And ctDNA was not detectable in one brain met only patient despite the obvious brain met.

We STILL have much to learn about melanoma and ctDNA.  However, it is CLEAR (after more than 7 years!!!) that analyzing ctDNA can be a helpful tool and should be routinely used in combination with other methods to monitor and evaluate melanoma patients - before and after therapy.  Thanks, ratties.  Demand the healthcare you deserve!!! - c

Strategies for treating melanoma subtypes - Acral, Mucosal, Uveal, Nodular, Lentigo

 

While melanoma, despite the huge improvements made when targeted and immunotherapies gained FDA approved in 2011 remains a very difficult cancer to treat and survive, the subtypes noted in the title make cutaneous melanoma look like a walk in the park.  This LINK takes you to reports on those subtypes that I have previously posted.  The link below takes you to a pretty thorough report addressing these particular forms of melanoma as well as a good history regarding BRAF status.  I have included much of the report below.  Words are from the authors - not me.  However, checking out the link is valuable, as it includes tables and references not reported here.

Emerging strategies to treat rare and intractable subtypes of melanoma. Gretchen and Vito. Pigment Cell Melanoma Res. Jan 2021.

Melanoma is the deadliest form of skin cancer, possessing a diverse landscape of subtypes with distinct molecular signatures and levels of aggressiveness. Although immense progress has been achieved therapeutically for patients with the most common forms of this disease, little is known of how to effectively treat patients with rarer subtypes of melanoma. These subtypes include acral lentiginous (the rarest form of cutaneous melanoma; AL), uveal, and mucosal melanomas, which display variations in distribution across (a) the world, (b) patient age-groups, and (c) anatomic sites. Unfortunately, patients with these relatively rare subtypes of melanoma typically respond worse to therapies approved for the more common, non-AL cutaneous melanoma and do not have effective alternatives, and thus consequently have worse overall survival rates. Achieving durable therapeutic responses in these high-risk melanoma subtypes represents one of the greatest challenges of the field. This review aims to collate and highlight effective preclinical and/or clinical strategies against these rare forms of melanoma.

INTRO - 

The melanoma field represents a paradigm for preclinical and clinical advancements in targeted and immune therapy modalities, with 13 new FDA-approved therapies since 2011. The catalyst for the development of targeted therapy modalities was the identification of activating NRAS mutations and BRAF mutations in 1984 and 2002... which paved the way for molecular stratification of the melanoma patient population. Approximately 45%–50% of non-acral lentiginous (AL) cutaneous melanoma patients have tumors that harbor activating BRAF mutations, with a single amino acid substitution of valine for glutamic acid at codon 600 (V600E) occurring in 90% of cases. Activating NRAS mutations at codon 12, 13, or 61 are detectable in 15%–20% of non-AL cutaneous melanoma patients and serve as an independent predictor of worse patient overall survival. Mutations of BRAF and NRAS are considered mutually exclusive; however, there are rare reports where both mutations exist in different regions of the same tumor or at different metastatic sites of the same patient. To date, it remains unclear whether the same melanoma cell can harbor both a BRAF and an NRAS mutation, or at the single-cell level, these mutations are indeed mutually exclusive.

With discoveries revealing that ~70% of non-AL cutaneous melanomas contain mutations constitutively activating the mitogen-activated protein kinase (MAPK) pathway came intense development of inhibitors capable of targeting various nodes of the mitogen-activated protein kinase (MAPK) pathway (i.e., BRAF, MEK, and ERK inhibitors) that continues to date. The first targeted therapy approved for the treatment of patients with BRAFV600E/K mutant melanoma was the small molecule inhibitor vemurafenib, an agent designed to have high specificity against the mutant V600E, V600K, V600D, and V600R forms of BRAF. Vemurafenib had response rates of ~48% in phase II and III clinical trials leading to the 2011 Food Drug and Agriculture (FDA) approval. A few years later, the combination of a BRAF inhibitor and a MEK inhibitor was observed to further increase the response rate to ~76% leading to the 2014 FDA approval of dabrafenib and trametinib. There are now three BRAF inhibitor plus MEK inhibitor combinations FDA approved for melanoma patients with BRAFV600E/K mutations (dabrafenib/trametinib, vemurafenib/cobimetinib, and encorafenib/binimetinib.

For patients with wild-type BRAF, treatment with BRAF inhibitors that specifically target V600E/K mutant BRAF may increase melanoma aggressiveness due to the paradoxical activation of wild-type BRAF and downstream MAPK pathway signaling. Preclinically, targeting downstream of BRAF with MEK inhibitors in BRAF-wild-type melanoma cells demonstrates the importance of the MAPK pathway for their survival, with significant anticancer activity. However, clinical trials testing multiple MEK inhibitors (i.e., binimetinib, trametinib) have concluded that although encouraging response rates and small increases in progression-free survival could be achieved in certain trials relative to dacarbazine, no significant increase in overall survival of patients with BRAF-wild-type melanoma was achieved with MEK inhibition. In an effort to increase MEK inhibitor efficacy, combination strategies with other agents (i.e., PI3K inhibitors, CDK4/6 inhibitors) are being clinically tested in the BRAF-wild-type (i.e., patients with or without NRAS-MT melanoma) setting after failure of immunotherapy. ERK inhibitors are also being clinically investigated to see if durable efficacy can be achieved in patients with wild-type BRAF, with reports showing the first-in-class ERK1/2 inhibitor ulixertinib has an acceptable safety profile and early evidence of clinical activity. Preclinical evidence suggests that concurrent inhibition of multiple nodes of the MAPK pathway in NRAS-mutant melanoma (i.e., MEK and ERK) may have synergistic activity on par with the BRAF inhibitor and MEK inhibitor combination in BRAF-mutant melanomas, and further studies evaluating this strategy are under way.

In parallel, large strides have been made in the development of immune checkpoint blockade strategies with the FDA approval of antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA4, ipilimumab) in 2011 and programmed cell death 1 (PD1, pembrolizumab, nivolumab) in 2014  and the combination of ipilimumab and nivolumab in 2015. Immune checkpoint blockade describes the use of therapeutic antibodies that overcome immunosuppressive checkpoints with the goal of unchaining antitumor immune responses. CTLA4 and PD-1 are both receptors that suppress effector T-cell activity. These immunotherapy-based strategies elicit long-lasting responses in a subset of patients and represent a therapeutic strategy suitable for all genotypes of non-AL cutaneous melanoma. However, the majority of patients treated with immunotherapy progress within 5 years due to poorly understood primary resistance mechanisms, and clinicians still cannot reliably discriminate which patients will respond or not respond. Both tumor intrinsic (i.e., insufficient tumor antigenicity, tumor interferon-γ signaling, tumor stemness) and extrinsic (i.e., regulatory T cells, myeloid-derived suppressor cells) resistance mechanisms have been reported, and there are intense efforts focused on overcoming these therapeutic hurdles to further increase the efficacy of immune checkpoint blockade strategies.

The promising efficacy of these new therapeutic strategies has been demonstrated largely in non-AL cutaneous melanoma patients with either superficial spreading melanoma (SSM), nodular melanoma (NM), or lentigo maligna melanoma (LMM). SSM, NM, and LMM represent the most common forms of melanoma in Caucasians (>85% of cases). It is important to appreciate that most of the recent pivotal discoveries in melanoma were performed on SSM cell lines, short-term cultures, animal models, and tumor biopsies taken from patients with SSM largely due to their greater availability. AL melanoma represents the fourth and rarest subtype of cutaneous melanoma. In addition, mucosal melanoma and uveal melanoma are other rare subtypes of melanoma that are non-cutaneous in origin. The efficacy of immune checkpoint blockade is lower in rarer subtypes of melanoma relative to patients with non-AL cutaneous melanoma, which will be discussed later. There is also little information regarding the efficacy of combination BRAF inhibitor and MEK inhibitor therapy in these subtypes. 

Acral - 

Acral lentiginous melanoma is an uncommon yet relatively aggressive subtype of CMM that accounts for 2%–3% of all melanoma cases. AL melanoma arises on sun-protected, glabrous skin of the soles, palms, and nail beds. AL melanoma has been historically associated with worse 10-year survival rates relative to other forms of CMM (67.5% vs. 87.5%). Further, 10-year AL melanoma survival rates are highest in non-Hispanic Whites (69.4%), intermediate in Blacks (71.5%), and lowest in Hispanic Whites (57.3%) and Asian/Pacific Islanders (54.1%), as found by the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute evaluating data from 17 population-based cancer registries from 1986 to 2005. Another analysis of AL melanoma prognostic features in a cohort of German, Swiss, and Austrian patients suggests no significant difference exist relative to other subtypes of cutaneous melanoma; however, this conclusion may stem due to differential ethnicity landscapes between this patient cohort and that in the SEER study. There does not appear to be a gender bias, with a similar frequency between men and women and a comparable median age of diagnosis of 63.1 years for men and 62.2 years for women. The incidence of AL melanoma increases with age, and for reasons poorly understood, men are twice as likely to develop AL melanoma relative to women after the age of 80.

The distribution of AL melanoma varies geographically among populations throughout the world. While AL melanoma represents only ~2%–3% of all melanoma cases in Caucasian populations, AL melanoma makes up 50%–80% of all cases in non-Caucasian individuals in the United States (i.e., those of African, Latin American, and Asian descent). Furthermore, the incidence in Hispanic Whites doubles compared to non-Hispanic Whites after the aged of 70. A 2009 SEER study found the overall incidence rates of AL melanoma were similar between non-Hispanic Whites and Blacks; however, Hispanic Whites have statistically higher incidence rates relative to non-Hispanic Whites . Updated epidemiological studies should be performed to continue understanding the differential incidence trends that may exist across different ethnicities. Of note, the incidence of other subtypes of cutaneous melanoma (i.e., NM, SSM) is much lower in non-Caucasians relative to Caucasians. As this subtype of melanoma is not related to ultraviolet radiation (UV), there are different theories of the cause of AL melanoma. Some reports state that trauma and pressure in the foot (a predilected area of AL) is causal. However, the hand is also exposed to trauma but its location is less favorable. The main sites of AL melanoma metastases are the lungs, distant lymph nodes, scalp, contralateral limb, and liver.

Acral lentiginous melanomas possess a significantly lower mutational burden relative to the more common cutaneous melanoma subtypes, likely due to the sun-protected locations they arise from. BRAF mutations in are found in 1 in every 5 Al melanoma patients, leaving ~80% ineligible to receive BRAF inhibitor and combination BRAF/MEK inhibitor strategies . Therefore, new targets specific for AL melanoma are needed. 80% of AL melanomas display genetic aberrations of cyclin-dependent kinase 4/6 (CDK4/6) pathway-related genes (i.e., amplification of CDK4 and CCND1, and/or loss of CDK2NA), representing the most frequent copy number alteration detected . Additionally, activating KIT mutations are present in ~6% of cases. AL melanoma displays similar incidence of NRAS mutations as non-AL cutaneous melanoma, detectable in 15%–28% of AL melanoma patients, and NRAS mutations are an independent prognostic factor of worse overall survival.

Considerable barriers exist to treat patients with AL melanoma: (a) a contrasting genomic and genetic landscape relative to non-AL cutaneous melanomas, (b) unclear targetable drivers, and (3) sparse experimental models available for preclinical drug development. Unfortunately, FDA-approved targeted therapy strategies for melanoma are not available for the majority of AL melanoma patients (i.e., BRAF inhibitors since AL melanoma has a low frequency of BRAF mutations), and the efficacy of immune checkpoint blockade strategies is not well known in AL melanoma, with differing overall response rates (ORR) differing by country. For example, the ORR of anti-PD-1 in AL melanoma patients was found to be similar to that in non-AL cutaneous melanoma patients within the United States. In contrast, the ORR was 66.7% for SSM patients and 28.6% of AL melanoma patients in a recent Japanese study, suggesting the efficacy of immune checkpoint blockade may vary with ethnicity. The lower mutational burden observed in AL melanoma cases is thought to drive the reduced efficacy of immune checkpoint inhibitor strategies (e.g., PD-1 blockade) in patients. Although AL melanoma patients with Kit mutations can be treated with a KIT inhibitor per National Comprehensive Cancer Network (NCCN) guidelines, resistance mechanisms that reactivate downstream MAPK and PI3K pathway signaling have been suggested to blunt long-term durability. Due to the high percentage of AL melanoma tumors with CDK4/6-pathway aberrations, CDK4/6 inhibition represents one of the most promising targeted therapy strategies for AL melanomas clinically. However, durable responses are not observed in all patients due to resistance and CDK4/6 inhibitor-based combinations will likely be needed to improve the curative rate for patients with AL melanoma. Preclinical investigation to optimize targeted therapy strategies has not been extensively performed in AL melanoma models, but the rich body of literature that exists from studies in non-AL cutaneous melanoma models strongly suggests that single-agent approaches will not be durable due to the nearly universal onset of resistance. In SSM models, treatment with a MAPK pathway inhibitor plus a CDK4/6 inhibitor has shown synergistic activity in BRAF-MT and BRAF-wild-type settings; however, residual disease persists. Resistance mechanisms to CDK4/6 inhibitors and/or MEK inhibitors must be delineated to develop combination strategies that produce durable responses in AL melanoma patients.

Mucosal Melanoma - 

Mucosal melanoma (MM) is one of the rarest types of melanoma, accounting for only 1% of all cases, and has a significantly worse prognosis relative to the other subtypes. Distinct from cutaneous melanoma, MM arises from melanocytes located in mucosal membranes inside the body (i.e., genitourinary, anorectal, nasopharyngeal). The head and neck (55), vulva (18), and anus (24) are the most common observed sites; however, MM can also occur in the gut, lungs, and urinary track. It is rarely diagnosed at early stages due to difficult visual detection, which is much more tractable for cutaneous subtypes of melanoma. The overall median age of diagnosis is 70 years, with the exception of MMs arising in the mouth that manifest more frequently in younger patients. The incidence of MM has been stable for the last few years with the exception of MM in the genital tract, which is higher in females relative to males for reasons not clearly understood.

Approximately 3%–15% of MMs harbor an activating mutation in BRAF, with ~63% located on the V600 codon and 37% located on a non-V600 codon. This is in contrast to non-AL cutaneous melanomas where <10% of BRAF mutations are outside of the V600 codon, and more closely resembles the high prevalence of non-V600 mutations found in 48% of lung adenocarcinomas. A closer analysis of the most common non-V600 mutations reveals (a) a difference between the frequency of mutations on D594, G469, and K601 between non-AL cutaneous melanomas and MMs, and (b) convergence in the non-V600 mutational landscape between MM and lung cancers where mutations are often associated with genotoxic agents.

In regard to NRAS mutations, approximately 12% of MMs harbor activating mutations, which is lower relative to cutaneous melanomas where NRAS mutations occur in 15%–20% of cases. There is also a divergence in the location of NRAS mutations between MM and cutaneous melanoma, with 54% located on codon 61 in MM versus 88% in cutaneous melanoma, and 46% located on codons 12 and 13 in MM versus 12% for cutaneous melanomas. Approximately 7%–22% of MMs have v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) somatic mutations or amplifications. MMs located in the genital area appear to be driven by mutations in SF3B1 which encodes the subunit 1 of splicing factor 3b, a component of the spliceosome that processes pre-mRNA into mature transcripts. A recent study analyzing the mutational landscape of MM identified IGF2R mutations in 31.7% of MM samples relative to 6.3% of SSM cases. Interestingly, a lower frequency of UV-induced DNA damage, a lower number of mutations and a link to high tobacco exposure have also been identified in MM.

Unfortunately, MM is typically detected at relatively more advanced states due to difficulty in early detection. The main treatment for MM differs slightly on where the tumor is located; however, like any other subtype of melanoma, patients are initially treated with surgical excision. MMs arising in the head and neck are treated with complete surgical excision of the tumor when the patient is in stages III and IVA. However, this is associated with a high rate of recurrence. MMs that have arisen in the vulvovaginal or anorectal area also receive radiation in addition to surgical tumor excision. Therapeutic efficacy may be improved in select patients when treatment is personalized by tumor mutational status. Clinical trials targeting KIT with imatinib show no clear effect in unselected metastatic melanoma patient populations, but encouraging clinical benefit has been observed with KIT inhibition specifically in patients with melanomas harboring KIT mutations (not in patients whose melanoma harbor KIT amplification only). Nonetheless, disease progression ultimately occurs in the majority of cases. These data support the practice of determining KIT mutational status for MM patients to have a higher chance of receiving additional clinical benefi. Subsequent phase II clinical trials now require a KIT alteration for enrollment. For the relatively small number of MM patients whose tumors harbor BRAF mutations (relative to the ~50% in non-AL cutaneous melanoma patients), treatment with combination BRAF inhibitor and MEK inhibitor therapy is available. However, the efficacy of targeted therapy specifically in the MM patient population is not completely understood due to the low number available for analysis.

The efficacy of immune checkpoint inhibitor therapy also remains unclear in MM patients, with conflicting evidence of whether MM patients respond as well as non-AL cutaneous melanoma patients. In one multi-institutional analysis of clinical trials focusing on all the subtypes of metastatic melanoma, patients with MM had similar responses compared with non-AL cutaneous melanoma patients when treated with anti-PD-1 single-agent therapy, with a progression-free survival of 3.9 months . In another pooled analysis, MM patients treated with nivolumab as monotherapy or nivolumab in combination with ipilimumab experienced reduced clinical benefit relative to non-AL cutaneous melanoma patients. MM patients experienced 50% shorter progression-free survival (3.0 months) relative to patients with non-AL cutaneous melanoma (6.2 months) for monotherapy (nivolumab) and for nivolumab plus ipilimumab (5.9 vs. 11.7 months. Another recent study combining axitinib (small molecule receptor tyrosine kinase inhibitor) with toripalimab (anti-PD-1) found a median progression-free survival of 7.5 months in among 29 patients with chemotherapy-naïve mucosal melanoma. Although these data suggest that MM patients may not achieve as much benefit with immune checkpoint inhibitor therapy as non-AL cutaneous melanoma patients, it should be considered that in each of the pooled analyses, the number of MM cases was only 10% of patients compared to 75% from cutaneous melanoma. Also notable, another prospective study where 44 patients with unresectable MM were treated with immune checkpoint inhibitors concluded that the site of origin for MM (i.e., vaginal, anal) may not have a significant impact on the objective response rate, which was 8.2% for ipilimumab and 35% for pembrolizumab. The lower mutational burden in MM relative to non-AL cutaneous melanoma may explain the decreased efficacy of immune checkpoint blockade in MM.

Uveal Melanoma -

Uveal melanoma (UM) is the most common form of ocular melanoma, as well as the most prevalent form of non-cutaneous melanoma, accounting for 5% of all melanomas . It most commonly arises in non-Hispanic Whites relative to other races (i.e., African and Asian Americans), with a slight predominance for men (52.3%) relative to women (47.7%). The incidence of UM has remained stable over the last few decades and is diagnosed in 4–5 per million individuals in the United States each year. The median age of diagnosis is 62, and the incidence of UM increases with age. Early detection of UM provides a favorable 85% survival rate; however, this survival rate significantly decreases to 15% once UM cells have disseminated. Approximately 50% of UM patients develop metastases, and among patients with metastatic disease, 90% have liver involvement and ~70% have liver-only disease. This is a distinct metastatic pattern relative to cutaneous melanoma or mucosal melanoma.

Unlike non-AL cutaneous melanomas, UMs have a much lower mutational burden due to the sun-protected site they arise from within the ocular cavity. Activating mutations in BRAF or NRAS are not detected (extremely rare) in tumor cells of UM patients. In contrast, the main drivers for UM are activating mutations of guanine nucleotide-binding protein G (GNAQ/11), splicing factor 3B subunit 1 (SF3B1), eukaryotic translation initiation factor (EIF1AX), and inactivating mutations of the tumor suppressor BRCA-associated protein-1 (BAP1). The GNAQ/11 genes encode specific GTP binding proteins that mediate signal transduction from the inner cell surface to the MAPK pathway through activation of the protein kinase C (PKC) enzyme. GNAQ and GNA11 mutations are mutually exclusive, and thus in total are detected in 85%–94% of UM across all stages of disease. Due to their detection in benign uveal nevi, GNAQ/11 mutations are thought to be early mutational events.

BAP1 (located on the short arm of chromosome 3) loss-of-function mutations are posited to serve as a predisposing factor for diverse hereditary cancers including mesothelioma, cutaneous melanoma, renal cell carcinoma, and UM. A recent comprehensive review identified that among 174 patients harboring germline BAP1 mutations, 130 developed tumors that were either UM (31% of cases), cutaneous melanoma (13% of cases), renal cell carcinoma (10% of cases), or MM (22% of cases). In UM, loss of BAP1 returns melanoma cells to a more stem cell-like state as BAP1 is involved in melanocyte differentiation. BAP1 is frequently mutated in metastasizing uveal melanomas, which supports the growing evidence that stem-like melanoma cell states drive elements of the metastatic cascade.

There has been a recent decline in UM patients treated solely with surgery due to micrometastases that develop years before primary tumor detection. The current approach for treatment of metastatic UM is radiation; however, the survival rate is not significantly improved relative to what is possible from surgery. There have been an array of clinical studies trying to identify efficacious therapeutic strategies for patients with metastatic UM. UM patients that possess GNAQ or GNA11 mutations can be treated in clinical trials with targeted therapy approaches specific for the MAPK pathway (i.e., MEK inhibitor, ERK inhibitor) as these tumors display elevated MAPK activity. Preclinical studies have shown that treatment of UM with a combination of a MAPK pathway inhibitor and a PKC inhibitor may provide synergistic efficacy relative to what is achievable by either agent alone. Clinical trials with selumetinib, a MEK inhibitor, reported a higher progression-free survival among UM patients (15.9 vs. 7 weeks); however, no clinically meaningful increase in overall survival was observed in comparison to the chemotherapeutic temozolomide in the metastatic setting (10.8 vs. 9.4 months). Additionally, preclinical studies identified that targeting the PI3K/AKT pathway (in GNAQ and GNA11 mutant xenograft models) in combination with a MEK inhibitor may be an effective treatment strategy for patients with GNAQ or GNA11 mutations; however, clinical trials using this combination have stopped due to low response rates and high toxicity. Inhibitors against bromodomain and extraterminal (BET) proteins have had encouraging activity preclinically in UM, which could be further increased by concurrent inhibition of escape mechanisms mediated by fibroblast growth factor receptors. Similarly, targeting microenvironment-derived factors including HGF can also increase MEK inhibitor efficacy against UM cells, preclinically. For UM with BAP1 mutations, it has been shown preclinically that treatment with a histone deacetylase (HDAC) inhibitor could be beneficial. Because BAP1 mutations are associated with loss of melanocytic differentiation, treatment with HDAC inhibitors (valproic acid) are postulated to inhibit the growth of uveal melanoma in vivo by inducing morphological differentiation.

While immune checkpoint inhibitors are the standard of care for cutaneous melanoma, UM has not yet had a phase III clinical trial for immune therapy. Small studies in UM patients (10 patients) treated with pembrolizumab (anti-PD-1) after treatment with ipilimumab reported a median progression-free survival of 18 weeks; ranging from 3.14 to 49.3 weeks. Of the eight evaluable patients, four rapidly progressed, one had stable disease, two had partial responses, and one had a complete response. Although this small study resulted in comparable results seen in patients with non-AL cutaneous melanoma, other studies suggest far lower response rates to single agent anti-PD-1 and combination anti-PD-1 plus anti-CTLA-4 in UM patients. An analysis of Danish UM patients observed partial responses in 7% of patients to anti-PD-1 and 21% to concurrent anti-PD-1 plus anti-CTLA-4. Metastatic UM patients treated with ipilimumab from two additional clinical studies had a median overall survival of 9 months (in contrast to 19.9 months in non-AL cutaneous melanoma). Despite the reduced efficacy of immune checkpoint blockade in UM patients, this option may represent the most effective strategy to date.

Nodular Melanoma -

Nodular melanoma represents the second most common subtype of melanoma, responsible for 10%–15% of total melanomas in Caucasians. NM is the melanoma subtype most associated with increased thickness at clinical presentation, which is attributed to the relatively poorer prognosis of patients with NM. The median age of diagnosis for NM is 53 years, with thicker tumors more common in older patients. NM is more common in women than men for reasons poorly understood and commonly presents de novo on the head, neck, or trunk of patients.

Activating BRAF mutations are detected in patients with NM at a slightly lower frequency relative to SSM, with 43%–47% of patients possessing mutations mostly (88% of cases) in V600E. A recent study identified evidence that BRAFV600E expression may serve as a prognostic marker in primary NM associated with ulceration and reduced survival. Preclinically, it was reported that hyperactivation of the downstream MAPK effector ribosomal protein S6 kinase (RSK1) is detectable in metastatic tumor tissues derived from NM to a higher extent relative to SSM. Activating NRAS mutations are detected at a significantly elevated frequency in NM relative to SSM in 30%–33% vs. 19% of cases, respectively. Interestingly, BRAF and NRAS mutations may not be as mutually exclusive in NM relative to SSM, with the identification of both mutations in the same tumor specimens when assessed by laser capture dissection followed by direct sequencing analysis of exons 11 and 15 of the BRAF gene and exons 1 and 2 of the NRAS gene. Additional high-throughput sequencing of patient-derived samples of single nucleotide variations (SNVs) expected to impact protein coding reveals NOTCH4, RPSKA6, BCL2L12, TERT, ERBB3, ZNF560, SSPO, and SNX31 to be significantly under-mutated in NM relative to SSM.

An analysis of the most recent Surveillance, Epidemiology, and End Results (SEER) cohort and the New York University (NRU) cohort suggests that relative to patients with metastatic SSM treated with BRAF inhibitor (BRAFi) therapy, patients with metastatic NM may respond worse to BRAFi for reasons not completely understood, suggesting the potential existence of distinct clinical and biological properties between NM and SSM. The observation of activated RSK1 via constitutive phosphorylation at the Ser-380 residue may explain the poorer efficacy of BRAFi and/or BRAFi/MEKi in patients with this melanoma subtype. In contrast, no significant difference in response rates and survival was detected in NM versus SSM among a cohort of 154 patients treated with either anti-CTLA-4, anti-PD-1, or the combination of both immune checkpoint inhibitor approaches. Immune checkpoint blockade may serve an ideal first-line therapy for patients with this subtype.

Lentigo Maligna - 

Lentigo maligna (LM) is the third most common subtype of melanoma, comprising roughly 4%–15% of all melanoma cases and its incidence has dramatically increased over the past few decades across the United States, and other regions of the world. LM melanoma typically presents on chronically sun-damaged (CSD) skin of the head and neck, appearing as an irregular brown macule commonly on the head and neck in the elderly. In contrast to the mean age of diagnosis of SSM between 40 and 60 years, the mean age of diagnosis for LM melanoma is 66–72 years. Credit is given to Sir John Hutchinson for the earliest description of LM melanoma in 1890. LM melanoma was initially referred to as “Hutchinson’s melanocytic freckle” due to the prevailing thought that it was benign, non-infectious lesion owing to its slow growing nature. Critical work by Ackerman and Silvers in the late 1970s–1980s finally led to wide acceptance of LM melanoma as a malignant disease worthy of clinical attention and intervention. Chronic ultraviolet radiation is the major risk factor for the development of LM melanoma, which differs from NM and SSM that are associated with intense intermittent ultraviolet radiation exposure. LM melanomas arise most frequently on the face and other sites of chronic sun damage which also differs from NM and SSM that arise most commonly on the trunk in men and legs in women. LM melanoma is thought to occur in older patients due to the increased lifetime sun and ultraviolet radiation exposure.

Lentigo maligna melanomas have a relatively high mutational burden compared to other melanoma subtypes due to chronic ultraviolet exposure. The frequency of activating BRAF mutations in LM is unclear, with reports finding 16.7%–53.4% of LM patients harboring BRAF mutations. The large variation may, in part, be attributed to the regional differences among tested patient tissue cohorts. In a Greek cohort, 16.7% of LM melanoma cases expressed BRAF mutations and 50% of LM cases in a Japanese cohort expressed BRAF mutations. When BRAF mutations are present, the V600K substitution is frequently observed (~77%) relative to the V600E (~23%) as observed in SSM, in this small set of 13 LM patient tumor samples. This finding is consistent with V600K mutations arising on chronically sun-damaged skin. Activating NRAS mutations have been reported to occur in ~8.1%–16% of LM cases .

The treatment of choice for patients with localized LM melanoma consists of surgical excision as first line of therapy, followed by radiation therapy with fractionated superficial radiotherapy, or topical imiquimod cream as an alternative to surgery. Once LM melanoma metastasizes to visceral organs, the five-year survival is similar to SSM. Interestingly, the efficacy of immune checkpoint blockade may be significantly higher in patients with LM melanoma relative to the other subtypes discussed. A study investigating the overall response rate (ORR) of anti-PD-1/PD-L1 in different subtypes of melanoma found patients with melanoma on CSD skin (including LM melanoma, desmoplastic melanoma, and subtype not-specified cases) exhibited an overall response rate of 70%, which fits the theory that cancer cells with high mutational burdens may be more sensitive to immune checkpoint blockade due to the increased presence of immune-stimulatory neoepitopes. Additional investigations on the efficacy of targeted and immune-based therapy are needed specifically for patients with LM melanoma to ensure the optimal treatment(s) is identified for this cohort and further improved through preclinical experimentation and clinical trials.

To date, this is the most comprehensive review of the data and treatments best suited for these melanoma subtypes that I have found.  So hoping that understanding and effective treatment options increase for these patients very soon.  -  c

The gut microbiome AGAIN - as it relates to immunotherapy for melanoma, other cancers, antibiotic use, and fecal transplants!

We have known that the bacteria, good and bad, within our intestines impact our health in ways, good and bad, for far longer than the current run of research and discussion of the microbiome sometimes remembers.  I posted this in 2015 - and it was old news then:  Cooties in our gut keep us skinny, smart and cure cancer!?????   For more on all things microbiome there are these:  The intestinal microbiome

Now, there are these additional reports:  

Relating the gut metagenome and metatranscriptome to immunotherapy responses in melanoma patients.  Peters, Wilson, Moran, et al.  Genome Med. 2019 Oct 9.

Recent evidence suggests that immunotherapy efficacy in melanoma is modulated by gut microbiota. Few studies have examined this phenomenon in humans, and none have incorporated metatranscriptomics, important for determining expression of metagenomic functions in the microbial community.

In melanoma patients undergoing immunotherapy, gut microbiome was characterized in pre-treatment stool using 16S rRNA gene and shotgun metagenome sequencing (n = 27). Transcriptional expression of metagenomic pathways was confirmed with metatranscriptome sequencing in a subset of 17. We examined associations of taxa and metagenomic pathways with progression-free survival (PFS) using 500 × 10-fold cross-validated elastic-net penalized Cox regression

Higher microbial community richness was associated with longer PFS in 16S and shotgun data (p < 0.05). Clustering based on overall microbiome composition divided patients into three groups with differing PFS; the low-risk group had 99% lower risk of progression than the high-risk group at any time during follow-up. Among the species selected in regression, abundance of Bacteroides ovatus, Bacteroides dorei, Bacteroides massiliensis, Ruminococcus gnavus, and Blautia producta were related to shorter PFS, and Faecalibacterium prausnitzii, Coprococcus eutactus, Prevotella stercorea, Streptococcus sanguinis, Streptococcus anginosus, and Lachnospiraceae bacterium 3 1 46FAA to longer PFS. Metagenomic functions related to PFS that had correlated metatranscriptomic expression included risk-associated pathways of L-rhamnose degradation, guanosine nucleotide biosynthesis, and B vitamin biosynthesis.

This work adds to the growing evidence that gut microbiota are related to immunotherapy outcomes, and identifies, for the first time, transcriptionally expressed metagenomic pathways related to PFS. Further research is warranted on microbial therapeutic targets to improve immunotherapy outcomes.

NOTE:  While what follows is positive news, many reports have shown that taking probiotics from a bottle do not provide the help our intestinal microbiome really needs, while a diet high in fiber and live cultures like those within yogurt, kefir, sauerkraut, and kimchi does.  Now, this:

Prebiotic-Induced Anti-tumor Immunity Attenuates Tumor Growth.  Li, Elmen, Segota, et al.  Cell Rep.  2020 Feb 11.

Growing evidence supports the importance of gut microbiota in the control of tumor growth and response to therapy. Here, we select prebiotics that can enrich bacterial taxa that promote anti-tumor immunity. Addition of the prebiotics inulin or mucin to the diet of C57BL/6 mice induces anti-tumor immune responses and inhibition of BRAF mutant melanoma growth in a subcutaneously implanted syngeneic mouse model. Mucin fails to inhibit tumor growth in germ-free mice, indicating that the gut microbiota is required for the activation of the anti-tumor immune response. Inulin and mucin drive distinct changes in the microbiota, as inulin, but not mucin, limits tumor growth in syngeneic mouse models of colon cancer and NRAS mutant melanoma and enhances the efficacy of a MEK inhibitor against melanoma while delaying the emergence of drug resistance. We highlight the importance of gut microbiota in anti-tumor immunity and the potential therapeutic role for prebiotics in this process.

When you need your cooties to work for you, it makes sense that killing them off with antibiotics would not serve you well.  Clearly, the development of antibiotics has prolonged and saved untold lives.  However, when they end up in the food chain, are used to treat viruses (for which they do NO GOOD) or are otherwise used inappropriately, real harm can result.  Not the least of which is a poor response in melanoma patients to immunotherapy.  There have been many concerning reports - Antibiotic use may diminish the positive effects of immunotherapy  

Now - there's this:

Antibiotic administration shortly before or after immunotherapy initiation is correlated with poor prognosis in solid cancer patients: An up-to-date systematic review and meta-analysis.  Yang, Wang, Yaun, et al.  Int Immunopharmacol.  2020 Aug.

Objective: Immune checkpoint inhibitors (ICIs) have recently achieved inspiring performance in improving the prognosis of various solid tumors. Gut microbiome plays a crucial modulatory role in the efficacy of ICIs, which can be influenced by antibiotic (ATB) administration. In this meta-analysis, we aimed to clarify the correlations of ATB administration with the prognosis of solid cancer patients receiving ICI treatment.

Method: The eligible literatures were searched using PubMed, Cochrane Library, Web of Science, and Clinical trials.gov databases before 29 February 2020. The correlations of ATB administration with overall survival (OS) and progression-free survival (PFS) were determined using Hazard ratios coupled with 95% confidence intervals.

Results: A total of 33 studies enrolling 5565 solid cancer patients receiving ICI treatment were included in this meta-analysis. As a whole, ATB administration was significantly correlated worse OS  and PFS. This significant association was then observed in the subgroup analysis based on region (except for OS in Europe), sample size, age, therapeutic strategy and ICI type. The similar results were also found in subgroup analysis for lung, renal cell (except for OS) and other cancers (such as melanoma) but not for mixed cancers. In addition, the ICI efficacy was more likely to be diminished by ATB administration within a time frame from 60 days before to 60 days after ICI initiation.

Conclusion: ATBs should be used cautiously in solid cancer patients receiving ICIs. However, further validations are still essential due to existing publication bias.

And this:

Is the survival of patients treated with ipilimumab affected by antibiotics? An analysis of 1585 patients from the French National hospital discharge summary database (PMSI).  Creen, Bertrand, Deley, et al.  Oncoimmunology.  2020 Nov.

Background: The gut microbiota has a key role in the regulation of the immune system. Disruption of the gut microbiota's composition by antibiotics might significantly affect the efficacy of immune checkpoint inhibitors. In a study of patients treated with ipilimumab, we sought to assess the relationship between overall survival and in-hospital antibiotic administration. 

Methods: Patients having been treated with ipilimumab between January 2012 and November 2014 were selected from the French National Hospital Discharge Summary Database. Exposure to antibiotics was defined as the presence of a hospital stay with a documented systemic bacterial infection in the 2 months before or the month after initiation of the patient's first ever course of ipilimumab. The primary outcome was overall survival. 

Results: We studied 43,124 hospital stays involving 1585 patients from 97 centers. All patients had received ipilimumab monotherapy for advanced melanoma. Overall, 117 of the 1585 patients (7.4%) were documented as having received systemic antibiotic therapy in hospital during the defined exposure period. The median overall survival time was shorter in patients with infection (6.3 months, vs. 15.4 months in patients without an infection. In a multivariate analysis adjusted for covariates, infection was still significantly associated with overall survival. 

Conclusions: In patients treated with ipilimumab for advanced melanoma, infection, and antibiotic administration in hospital at around the time of the patient's first ever course of ipilimumab appears to be associated with significantly lower clinical benefit.

In 2017 I reported on the positive effects of fecal transplants in poor little cancer affected mice - Back to the cooties in our guts....again!!!  Now, there seems to be a real benefit of same, for melanoma ratties!

Fecal microbiota transplant overcomes resistance to anti–PD-1 therapy in melanoma patients.  Davar, Dzutsev, McCulloch, et al.  Science. Feb 2021.

The composition of the gut microbiome influences the response of cancer patients to immunotherapies. Baruch et al. and Davar et al. report first-in-human clinical trials to test whether fecal microbiota transplantation (FMT) can affect how metastatic melanoma patients respond to anti–PD-1 immunotherapy. Both studies observed evidence of clinical benefit in a subset of treated patients. This included increased abundance of taxa previously shown to be associated with response to anti–PD-1, increased CD8+ T cell activation, and decreased frequency of interleukin-8–expressing myeloid cells, which are involved in immunosuppression. These studies provide proof-of-concept evidence for the ability of FMT to affect immunotherapy response in cancer patients.

Anti–programmed cell death protein 1 (PD-1) therapy provides long-term clinical benefits to patients with advanced melanoma. The composition of the gut microbiota correlates with anti–PD-1 efficacy in preclinical models and cancer patients. To investigate whether resistance to anti–PD-1 can be overcome by changing the gut microbiota, this clinical trial evaluated the safety and efficacy of responder-derived fecal microbiota transplantation (FMT) together with anti–PD-1 in patients with PD-1–refractory melanoma. This combination was well tolerated, provided clinical benefit in 6 of 15 patients, and induced rapid and durable microbiota perturbation. Responders exhibited increased abundance of taxa that were previously shown to be associated with response to anti–PD-1, increased CD8+ T cell activation, and decreased frequency of interleukin-8–expressing myeloid cells. Responders had distinct proteomic and metabolomic signatures, and transkingdom network analyses confirmed that the gut microbiome regulated these changes. Collectively, our findings show that FMT and anti–PD-1 changed the gut microbiome and reprogrammed the tumor microenvironment to overcome resistance to anti–PD-1 in a subset of PD-1 advanced melanoma.

 

Certainly something melanoma peeps who are not responding to anti-PD-1 might wish to discuss with their docs! 

And that brings us up-to-date with the most recent bits and bobs regarding the cooties in our guts!   Kefir smoothie, anyone? - c

After progression on anti-PD1 / anti-PDL1 treatment of melanoma

While many patients attain a response to immunotherapy (about 40% to either anti-PD1 product and about 60% to the ipi/nivo combo) and many of THOSE responses are durable, it is clear that way too many patients are left with an inadequate response or progression after those therapies.  So, then what?  Here is a recent post containing reports on how to address that scenario:  How to deal with recurrence on or after anti-PD-1 as adjuvant or treatment for active melanoma disease

Now, there's this ~

Outcomes after progression of disease with anti-PD-1/PD-L1 therapy for patients with advanced melanoma.  Patrinely, Baker, Davis, et al.  Cancer. 2020 August. 1.

Greater than one-half of patients with melanoma who are treated with antibodies blocking programmed cell death protein 1 receptor (anti-PD-1) experience disease progression. The objective of the current study was to identify prognostic factors and outcomes in patients with metastatic melanoma that progressed while they were receiving anti-PD-1 therapy.  The authors evaluated 383 consecutively treated patients who received anti-PD-1 for advanced melanoma between 2009 and 2019. Patient and disease characteristics at baseline and at the time of progression, subsequent therapies, objective response rate (ORR), overall survival, and progression-free survival were assessed.  

Of 383 patients, 247 experienced disease progression. The median survival after progression was 6.8 months. There was no difference in survival noted after disease progression based on primary tumor subtype, receipt of prior therapy, or therapy type. However, significantly improved survival after disease progression correlated with clinical features at the time of progression, including normal lactate dehydrogenase, more favorable metastatic stage (American Joint Committee on Cancer eighth edition stage IV M1a vs M1b, M1c, or M1d), mutation status (NRAS or treatment-naive BRAF V600 vs BRAF/NRAS wild-type or treatment-experienced BRAF-mutant), decreasing tumor bulk, and progression at solely existing lesions. After progression, approximately 54.3% of patients received additional systemic therapy. A total of 41 patients received BRAF/MEK inhibition (ORR of 58.6%, including 70.4% for BRAF/MEK-naive patients), 30 patients received ipilimumab (ORR of 0%), and 11 patients received ipilimumab plus nivolumab (ORR of 27.3%).   

The current study identified prognostic factors in advanced melanoma for patients who experienced disease progression while receiving anti-PD-1, including lactate dehydrogenase, stage of disease, site of disease progression, tumor size, and mutation status.

There is also this:

Patterns of failure after immunotherapy with checkpoint inhibitors predict durable progression-free survival after local therapy for metastatic melanoma.  Klemen, Wang, Feingold, et al.  J Immunother Cancer.  Jul 2020.  

Background: Checkpoint inhibitors (CPI) have revolutionized the treatment of metastatic melanoma, but most patients treated with CPI eventually develop progressive disease. Local therapy including surgery, ablation or stereotactic body radiotherapy (SBRT) may be useful to manage limited progression, but criteria for patient selection have not been established. Previous work has suggested progression-free survival (PFS) after local therapy is associated with patterns of immunotherapy failure, but this has not been studied in patients treated with CPI.  

Methods: We analyzed clinical data from patients with metastatic melanoma who were treated with antibodies against CTLA-4, PD-1 or PD-L1, either as single-agent or combination therapy, and identified those who had disease progression in 1 to 3 sites managed with local therapy. Patterns of CPI failure were designated by independent radiological review as growth of established metastases or appearance of new metastases. Local therapy for diagnosis, palliation or CNS metastases was excluded.  

Results: Four hundred twenty-eight patients with metastatic melanoma received treatment with CPI from 2007 to 2018. Seventy-seven have ongoing complete responses while 69 died within 6 months of starting CPI; of the remaining 282 patients, 52 (18%) were treated with local therapy meeting our inclusion criteria. Local therapy to achieve no evidence of disease (NED) was associated with three-year progression-free survival (PFS) of 31% and five-year disease-specific survival (DSS) of 60%. Stratified by patterns of failure, patients with progression in established tumors had three-year PFS of 70%, while those with new metastases had three-year PFS of 6%. Five-year DSS after local therapy was 93% versus 31%, respectively.  

Conclusions: Local therapy for oligoprogression after CPI can result in durable PFS in selected patients. We observed that patterns of failure seen during or after CPI treatment are strongly associated with PFS after local therapy, and may represent a useful criterion for patient selection. This experience suggests there may be an increased role for local therapy in patients being treated with immunotherapy.

Melanoma sucks great big green hairy stinky wizard balls!  Hang tough, peeps.  Hang tough! - c

Important stuff floating in our blood - tumor DNA, micro RNA, cytokines - can determine tumor burden, predict response, and side effects for melanoma patients!!!

Continuing from yesterday.....  Our blood is a fairly accessible information rich soup that can tell us all sorts of things about our bodies!!!  One important ingredient for melanoma patients is circulating tumor DNA.  Here's a load of prior reports: Circulating tumor DNA - to determine diagnosis, disease burden, response to therapy, etc  Here are a couple more reports:

Correlation between circulating tumour DNA and metabolic tumour burden in metastatic melanoma patients.  McEvoy, Warburton, Al-Ogaili, et al. BMC Cancer. 2018 Jul 9.

Circulating tumour DNA (ctDNA) may serve as a measure of tumour burden and a useful tool for non-invasive monitoring of cancer. However, ctDNA is not always detectable in patients at time of diagnosis of metastatic disease. Therefore, there is a need to understand the correlation between ctDNA levels and the patients' overall metabolic tumour burden (MTB).  Thirty-two treatment naïve metastatic melanoma patients were included in the study. MTB and metabolic tumour volume (MTV) was measured by 18F-fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT). Plasma ctDNA was quantified using droplet digital PCR (ddPCR).  CtDNA was detected in 23 of 32 patients. Overall, a significant correlation was observed between ctDNA levels and MTB. CtDNA was not detectable in patients with an MTB of greater than/= to 10, defining this value as the lower limit of tumour burden that can be detected through ctDNA analysis by ddPCR.  We showed that ctDNA levels measured by ddPCR correlate with MTB in treatment naïve metastatic melanoma patients and observed a limit in tumour size for which ctDNA cannot be detected in blood. Nevertheless, our findings support the use of ctDNA as a non-invasive complementary modality to functional imaging for monitoring tumour burden.

From validity to clinical utility: the influence of circulating tumor DNA on melanoma patient management in a real-world setting. Rose, Luber, Makell, et al. Mol Oncol. 2018 Aug 16.

Melanoma currently lacks a reliable blood-based biomarker of disease activity, although circulating tumor DNA (ctDNA) may fill this role. We investigated the clinical utility (i.e., impact on clinical outcomes and interpretation of radiographic data) of measuring ctDNA in patients with metastatic or high-risk resected melanoma. Patients were prospectively accrued into greater than/= to 1 of 3 cohorts, as follows. Cohort A: patients with radiographically-measurable metastatic melanoma who underwent comparison of ctDNA measured by a BEAMing digital PCR assay to tissue mutational status and total tumor burden; when appropriate, determinations about initiation of targeted therapy were based on ctDNA data. Cohorts B and C: patients with BRAF- or NRAS-mutant melanoma who had either undergone surgical resection of high-risk disease (cohort B) or were receiving or had received medical therapy for advanced disease (cohort C). Patients were followed longitudinally with serial ctDNA measurements with contemporaneous radiographic imaging to ascertain times to detection of disease activity and progressive disease, respectively. The sensitivity and specificity of the ctDNA assay was 86.8% and 100%, respectively. Higher tumor burden and visceral metastases were found to be associated with detectable ctDNA. In 2 patients in cohort A, ctDNA test results revealed a targetable mutation where tumor testing had not; both patients experienced a partial response to targeted therapy. In 4 of 30 patients with advanced melanoma, ctDNA assessments indicated evidence of melanoma activity that predicted radiographic evidence of disease progression by 8, 14, 25 and 38 weeks, respectively. CtDNA was detectable in 3 of these 4 patients coincident with radiographic evaluations that alone were interpreted as showing no evidence of neoplastic disease. Our findings provide evidence for the clinical utility of integrating ctDNA data in managing patients with melanoma in a real-world setting.

Among the many bio-markers present in our blood, there's also circulating RNA.   Prior reports:  RNA and biomarkers generally  Now, this:

Extracellular microvesicle microRNAs as predictive biomarkers for targeted therapy in metastastic cutaneous malignant melanoma.  Svedman, Loncharoenkal, Bottaj, et al. PLoS One. 2018 Nov.

Mitogen activated-protein kinase pathway inhibitors (MAPKis) improve treatment outcome in patients with disseminated BRAFV600 mutant cutaneous malignant melanoma (CMM) but responses are of limited duration due to emerging resistance. Although extensive research in mechanisms of resistance is being performed, predictive biomarkers for durable responses are still lacking. We used miRNA qPCR to investigate if different levels of extracellular microvesicle microRNA (EV miRNA) in matched plasma samples collected from patients with metastatic IV BRAFV600 mutated CMM before, during and after therapy with MAPKis could serve as predictive biomarkers.  EV miRNAs were extracted from plasma samples from 28 patients collected before and during therapy, measured by quantitative PCR-array and correlated to therapy outcome. Increased levels of EV let-7g-5p during treatment compared to before treatment were associated with better disease control with MAPKis. Elevated levels of EV miR-497-5p during therapy were associated with prolonged progression free survival (PFS).  EV miRNAs let-7g-5p and miR-497-5p were identified as putative novel predictive biomarkers of MAPKi treatment benefit in metastatic CMM patients highlighting the potential relevance of assessing EV miRNA during and after treatment to unravel novel mechanisms of resistance.

Circulating cytokines are substances like interleukin, interferon, and growth factors, that cells in our immune system secrete in order to affect other cells. Here's a report for a little background:  Eosinophilia with Nivo and Pembro - A predictor of success?!!
Here they are being examined as predictors of toxicity to immunotherapy:

Circulating cytokines predict immune-related toxicity in melanoma patients receiving anti-PD-1-based immunotherapy. Lim, Lee, Gide, et al. Clin Cancer Res. 2018 Nov 8.  

Combination PD-1 and CTLA-4 inhibitor therapy has dramatically improved the survival of patients with advanced melanoma but is also associated with significant immune-related toxicities. This study sought to identify circulating cytokine biomarkers of treatment response and immune-related toxicity.  The expression of 65 cytokines was profiled longitudinally in 98 melanoma patients treated with PD-1 inhibitors, alone or in combination with anti-CTLA-4, and in an independent validation cohort of 49 patients treated with combination anti-PD-1 and anti-CTLA-4. Cytokine expression was correlated with RECIST response and immune-related toxicity, defined as toxicity that warranted permanent discontinuation of treatment and administration of high dose steroids.

Eleven cytokines were significantly upregulated in patients with severe immune-related toxicities at baseline and early during treatment. The expression of these eleven cytokines was integrated into a single toxicity score, the CYTOX score, and the predictive utility of this score was confirmed in the discovery and validation cohorts. 

The CYTOX score is predictive of severe immune-related toxicity in melanoma patients treated with combination anti-CTLA-4 and anti-PD-1 immunotherapy. This score, which includes pro-inflammatory cytokines such as IL-1a, IL-2 and IFNa2, may help in the early management of severe, potentially life-threatening immune-related toxicity.

Hoping for much more consistency and use of these relatively simple tests in order to reap better treatment outcomes for melanoma patients in 2019!!! - c