ASCO 2017: Circulating DNA to measure response in melanoma

Wouldn't it be great if we could do a simple lab draw to determine the type of tumor, as well as tumor burden a patient has??  With such a test we could minimize use of painful biopsies, decrease repeated exposure to radiation via scans, and could much more rapidly determine whether a patient's tumor burden is decreasing in a positive response to a given therapy....or not!

I've been posting studies addressing these possibilities for a while...
From 2014:  With immunotherapy tumors can grow or reappear...even though it is working. Will DNA analysis clarify response???

From 2015:  PCR testing for melanoma

PCR testing for circulating melanoma DNA....one mo one!!

Circulating Tumor Cells...how they may eventually impact melanoma diagnosis and response to therapy

From 2016:  Here, I actually broke down all the various biomarkers, what they are and what they mean ~ Biomarkers - blood components, circulating tumor cells AND of the tumor itself

Then there were these:  BRAF testing via blood rather than tumor tissue

Blood tests to diagnose, check response to therapy, and use as follow-up in melanoma!

From 2017:  Circulating DNA predicts response to anti-PD-1

Circulating tumor DNA provide valid way to monitor response to anti-PD-1 therapy for melanoma....AGAIN!!!

Now...there's this:

Circulating tumor DNA as a predictor for response to treatment in BRAF V600E mutant malignant melanoma.

ASCO 2017. J Clin Oncol 35, 2017. Braune, Buboff, Follo, et al.

Background: Available biomarkers LDH and S100B possess limited sensitivity and specificity to predict outcome in melanoma. In this pilot study we evaluated the use of circulating tumor (ct)DNA harboring BRAF and NRAS mutations as a predictive biomarker for treatment response and progression-free survival (PFS) in patients with locally advanced or metastatic melanoma. Methods: We analyzed 89 retrospective plasma samples from 32 unselected pts, and 158 samples from 12 pts included in a prospective trial (DRKS00009507). We included stage III disease with planned resection or stage IV disease before initiation or change of medical treatment. Blood samples were taken at baseline at d +8, d +28, and thereafter at 3 months intervals for up to two years. We developed a hydrolysis probe based, Locked Nucleic Acid assay to detect BRAF V600E and wild type ctDNA by droplet digital PCR. Results were correlated with LDH, S100B and PFS. Results: Sensitivity of BRAF V600E specific assay was 0.01% with a limit of Blank of 0.28 copies/well. Of 31 stage IV pts with retrospective samples, 23 were positive for BRAF V600E ctDNA at least once (74%). Positive pts had a mean of 9 (range: 1-17) and 483 (range: 0.1-16,388) BRAF V600E copies/mL for stage III and stage IV respectively. The presence of ctDNA at baseline predicted poor PFS. A negative slope in BRAF V600E ctDNA was a favorable prognostic factor for PFS with a median PFS of 3.42 vs. 2.56 months (Range 1.87-8.9 vs. 0.89-5.02). Residual ctDNA at the first time point after initiation or change of treatment was related to a shorter PFS. Based on 144 measurement pairs, BRAF ctDNA strongly correlated with S100 and LDH. Conclusions: Residual ctDNA early after change or institution of treatment predicted tumor progression at first clinical response assessment. A positive to negative conversion or a decrease indicated a more favorable course. These data support the use of ctDNA as an early predictive marker for treatment response. We will examine whether two or more detected mutations indicate clonal heterogeneity and confer adverse prognosis. 

Here, using a blood test to check for bits of circulating tumor DNA for BRAF V600E and wild type, the researchers looked at 89 previously drawn blood samples from 32 patients along with 158 blood samples from 12 patients in this trial.  These samples were collected at baseline, and in roughly 1 week, 1 month and then q 3 months for up to 2 years.  Examination of the previously drawn samples showed that 23 of the 31 Stage IV patients were positive for BRAF V600E circulating tumor cells in their blood at least once (74%).  The presence of circulating DNA from tumor cells at baseline was a poor indicator for PFS (progression free survival), while decreasing levels of same was a favorable prognostic factor for PFS.  Patients that still had circulating DNA from tumor cells in their blood "early after a change or institution of treatment predicted tumor progression at first clinical response assessment".  If the test changed from being positive for the ctDNA to negative for it, or if there was a decrease in the level measured, the patients had a more favorable course.

Makes sense, right?  If you have a lot of circulating tumor DNA in your blood...that's not good.  If you still have ctDNA floating around after you have started a new treatment...it doesn't bode well for you to respond well to that treatment.  However, if you have little ctDNA period, or if the amount you have is decreasing with your treatment...it is likely that you will do well!!!  Think how much more quickly we could get a patient on the treatment that works for them with a tool like this!!!  I think we've beat around this bush for long enough!!!  Let's make peripheral blood sample testing for circulating tumor DNA a reality!! - 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

PCR testing for melanoma

Polymerase chain reaction (PCR) is a technique that is used to amplify trace amounts of DNA (and in some instances, RNA) located in or on almost any liquid or surface where DNA strands may be deposited.  It is an exceedingly sensitive technique to detect molecules.  In everyday medicine it can be used to check for the presence of a wide variety of substances - pertussis from a nasal swab, chlamydia and gc in urine, viral load of HIV patients from their blood sample, fungus in skin scrapings, and even genetic mutations.  It would be super cool if we could utilize this technique to accurately identify the presence and characteristics of melanoma cells....both for diagnosis as well as monitoring effects of treatment.  Here are some peeps who are working on it:

SNPase-ARMS qPCR:  Ultrasensitive Mutation-Based Detection of Cell-Free Tumor DNA in Melanoma Patients.  PLoS One. 2015 Nov 12.  Stadler, Eder, Pratscher, et al.

"Cell-free circulating tumor DNA in the plasma of cancer patients has become a common point of interest as indicator of therapy options and treatment response in clinical cancer research. Especially patient- and tumor-specific single nucleotide variants that accurately distinguish tumor DNA from wild type DNA are promising targets. The reliable detection and quantification of these single-base DNA variants is technically challenging. Currently, a variety of techniques is applied, with no apparent "gold standard". Here we present a novel qPCR protocol that meets the conditions of extreme sensitivity and specificity that are required for detection and quantification of tumor DNA. By consecutive application of two polymerases, one of them designed for extreme base-specificity, the method reaches unprecedented sensitivity and specificity. Three qPCR assays were tested with spike-in experiments, specific for point mutations BRAF V600E, PTEN T167A and NRAS Q61L of melanoma cell lines. It was possible to detect down to one copy of tumor DNA per reaction , at a background of up to 200 000 wild type DNAs. To prove its clinical applicability, the method was successfully tested on a small cohort of BRAF V600E positive melanoma patients."

Still needs to be tested on a greater scale...but sounds like progress. - c

Circulating tumor cells/DNA in melanoma!!! Have I not mentioned this a ZILLION times????

There are many blood (and other fluid) markers, all much easier to collect that actual tumor samples, that can be used to diagnosis melanoma, determine tumor type, prognosis and response to therapy.  Here's a link to zillions of posts:  Neutrophil-to-lymphocyte ratio and outcomes in melanoma. Yep, AGAIN!!!!!  More here:  Simple blood tests that tells us where we are with our melanoma....AGAIN (and again, and again, and again)!!!

And there is this (with tons of links within) on circulating tumor cells/DNA alone:  ASCO 2017: Circulating DNA to measure response in melanoma

Now, these:

Circulating Tumor Cells in Stage IV Melanoma Patients. Hall, Ross, Bowman, et al.J Am Coll Surg. 2018 May 7.

Management of stage IV melanoma patients remains a challenge. In spite of promising new therapies, many patients develop resistance and progression. The aim of this pilot study was to determine if CTCs are associated with shortened (180-day) progression-free survival (PFS) following a baseline CTC assessment in stage IV melanoma patients.

A baseline CTC assessment was performed in 93 stage IV melanoma patients using a commercially available immunomagnetic system. The presence of greater than/equal to 1 CTC was considered a positive result. A Cox multivariable regression model was used to evaluate the association between presence of CTCs at baseline and PFS, after adjusting for covariables. Kaplan-Meier curves and a log-rank test were used to summarize and compare unadjusted PFS for patients stratified by CTC positivity.

Median follow-up was 17 months; mean age was 55 years. Thirteen of 93 (14%) patients had no evidence of disease (NED) at baseline CTC assessment. One or more CTC was detected in 39/93 (42%) of patients at baseline. CTCs were not associated with primary melanoma features or NED status. Twenty-eight of 93 (30%) patients progressed within 180 days of baseline draw, with 20/39 (51%) of the CTC positive patients relapsing compared to 8/54 (15%) of the CTC negative patients. In adjusted Cox models, a significant association was found suggesting worse PFS within 180 days for CTC positive patients at baseline (vs. CTC negative).

One or more CTCs at baseline were associated with progression within 180 days in stage IV melanoma patients. This information warrants further study of CTCs as a means of identifying patients at high-risk for disease progression.

Measuring circulating tumor cells can predict response and progression!! And, this.....

Quantitative monitoring of circulating tumor DNA predicts response of cutaneous metastatic melanoma to anti-PD1 immunotherapy.  Herbreteau, Vallee, Knol, et al. Oncotarget. 2018 May 18.

Immunotherapies have changed the medical management of metastatic melanoma. However, the early detection of patients who do not respond to these treatments is a key issue. We evaluated the quantitative monitoring of circulating tumor DNA (ctDNA) as an early predictor of response to anti-PD1. Patients treated with anti-PD1 for metastatic mutated melanoma were selected. The somatic alteration detected on the tumor tissue was quantified on plasma DNA by digital PCR (dPCR) at treatment initiation, after 2 and 4 weeks of treatment, and then every 4 weeks until progression. The absence of biological response (defined as a significant decrease in the amount of ctDNA relative to the baseline level) after 2 weeks of treatment was associated with a lack of clinical benefit under anti-PD1. In the presence of a biological response at week 2, detection of subsequent biological progression (significant increase in the amount of ctDNA relative to its nadir) was 100% predictive of progressive disease, on average 75 days prior to radiological detection. Patients with a persistent biological response beyond week 16 did not experience any progressive disease and exhibited sustained responses. In conclusion, we show that quantitative monitoring of ctDNA, using criteria accounting for dPCR measurement imprecision, allows the early and specific detection of patients who do not respond to anti-PD1 therapy.

When circulating tumor DNA was monitored in patients treated with immunotherapy, no significant decrease in the ctDNA measured in the blood was associated with lack of benefit from anti-PD-1 AND an increase in the ctDNA "was 100% predictive of progressive disease, on average 75 days prior to radiological detection."  Think what being able to change treatments, from one that is not working to one that might serve you better, 75 days sooner, could mean for patient outcomes!!!  And, there's this:

Evaluating Circulating Tumor DNA From the Cerebrospinal Fluid of Patients With Melanoma and Leptomeningeal Disease. Ballester, Glitza, Douse, et al.  J Neuropathol Exp Neurol. 2018 Jun 4.  

Circulating tumor DNA (ctDNA) refers to tumor-derived cell-free DNA that circulates in body fluids. Fluid samples are easier to collect than tumor tissue, and are amenable to serial collection at multiple time points during the course of a patient's illness. Studies have demonstrated the feasibility of performing mutation profiling from blood samples in cancer patients. However, detection of ctDNA in the blood of patients with brain tumors is suboptimal. Cerebrospinal fluid (CSF) can be obtained via lumbar puncture or intraventricular catheter, and may be a suitable fluid to assess ctDNA in patients with brain tumors. We detected melanoma-associated mutations by droplet-digital PCR (ddPCR) and next-generation sequencing in ctDNA obtained from the CSF (CSF-ctDNA) of melanoma patients with leptomeningeal disease. There is a strong correlation between mutation detection by ddPCR, the presence of circulating tumor cells in CSF and abnormalities in the MRI. However, approximately 30% of CSF samples that were negative or indeterminate for the presence of tumor cells by microscopic examination were positive for CSF-ctDNA by ddPCR. Our results demonstrate that CSF is a suitable fluid for evaluating ctDNA and ddPCR is superior to CSF-cytology for analysis of CSF in melanoma patients with leptomeningeal disease.

Here researchers are simply noting that the cerebral spinal fluid can be monitored in the same manner blood samples can be.

I have been noting these reports for YEARS!!!!!!!!!!!!!!!!!!  If I am aware of these options, then oncologists should know about these study results and assay possibilities far better than I.  These minimally invasive, but highly informative tests, should be readily available and utilized as part of the arsenal to diagnosis, predict response, determine progression, find appropriate therapy, and ultimately save lives of melanoma patients ~ TODAY!!!!  - c

PCR testing for circulating melanoma DNA....one mo one!!

Applications for quantitative measurement of BRAF V600 mutant cell-free tumor DNA in the plasma of patients with metastatic melanoma.  Schreuer, Meersseman, Herrewegan, et al.  Melanoma Res.  2015 Dec 3. 

"Small fragments of cell-free DNA that are shed by normal and tumor cells can be detected in the plasma of patients with advanced melanoma. Quantitative measurement of BRAF V600 mutant DNA within the cell-free DNA holds promise as a tumor-specific biomarker for diagnosis and therapeutic monitoring in patients with BRAF V600 mutant melanoma. Allele-specific quantitative PCR analysis for BRAF V600 E/E2/D/K/R/M mutations on DNA extracted from 1 ml of plasma is currently under evaluation in a number of ongoing prospective clinical studies. We report five patient cases that indicate the potential applications and utility of quantitative measurements of BRAF V600 mutant cell-free tumor DNA as a diagnostic test and as a therapeutic monitoring tool in stage IV melanoma patients treated with BRAF-targeted therapy or immunotherapy. Finally, we offer novel insights into the dynamics of cell-free tumor DNA in melanoma."

So this is the bandwagon many melanoma specialists are on at the moment as is evident by this article and the two recent posts noted below - all from differing sets of researchers! And, that's not a bad thing.  My cynical self sees it as a race to the patented, FDA approved, money making test...for this bio-firm or for that set of researchers.   My more hopeful self sees a potential method for minimally invasive, accurate diagnosis of the presence and type of melanoma an individual is dealing with, as well as a way to measure tumor burden and response to therapy.

Here's hoping!  - c

Circulating tumor DNA (ctDNA) the little bits of tumor floating in our blood and how they can impact melanoma patients

In this post, replete with many links within - Circulating tumor DNA to monitor and predict response in melanoma patients - yes - AGAIN!!!!  - from earlier this year, I wrote:  "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."  Now there are these reports: 

Circulating tumour DNA in patients with advanced melanoma treated with dabrafenib or dabrafenib plus trametinib: a clinical validation study.  Syeda, Wiggins, Corless, et al.  Lancet Oncol.  Feb 2021.

Background: Melanoma lacks validated blood-based biomarkers for monitoring and predicting treatment efficacy. Cell-free circulating tumour DNA (ctDNA) is a promising biomarker; however, various detection methods have been used, and, to date, no large studies have examined the association between serial changes in ctDNA and survival after BRAF, MEK, or BRAF plus MEK inhibitor therapy. We aimed to evaluate whether baseline ctDNA concentrations and kinetics could predict survival outcomes.

Methods: In this clinical validation study, we used analytically validated droplet digital PCR assays to measure BRAFV600-mutant ctDNA in pretreatment and on-treatment plasma samples from patients aged 18 years or older enrolled in two clinical trials. COMBI-d (NCT01584648) was a double-blind, randomised phase 3 study of dabrafenib plus trametinib versus dabrafenib plus placebo in previously untreated patients with BRAFV600 mutation-positive unresectable or metastatic melanoma. Patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. COMBI-MB (NCT02039947) was an open-label, non-randomised, phase 2 study evaluating dabrafenib plus trametinib in patients with BRAFV600 mutation-positive metastatic melanoma and brain metastases. Patients in cohort A of COMBI-MB had asymptomatic brain metastases, no previous local brain-directed therapy, and an ECOG performance status of 0 or 1. Biomarker analysis was a prespecified exploratory endpoint in both trials and performed in the intention-to-treat populations in COMBI-d and COMBI-MB. We investigated the association between mutant copy number (baseline or week 4 or zero conversion status) and efficacy endpoints (progression-free survival, overall survival, and best overall response). We used Cox models, Kaplan-Meier plots, and log-rank tests to explore the association of pretreatment ctDNA concentrations with progression-free survival and overall survival. The effect of additional prognostic variables such as lactate dehydrogenase was also investigated in addition to the mutant copy number.

Findings: In COMBI-d, pretreatment plasma samples were available from 345 (82%) of 423 patients and on-treatment (week 4) plasma samples were available from 224 (53%) of 423 patients. In cohort A of COMBI-MB, pretreatment and on-treatment samples were available from 38 (50%) of 76 patients with intracranial and extracranial metastatic melanoma. ctDNA was detected in pretreatment samples from 320 (93%) of 345 patients (COMBI-d) and 34 (89%) of 38 patients (COMBI-MB). When assessed as a continuous variable, elevated baseline BRAFV600 mutation-positive ctDNA concentration was associated with worse overall survival outcome, independent of treatment group and baseline lactate dehydrogenase concentration, in COMBI-d. A ctDNA cutoff point of 64 copies per mL of plasma stratified patients enrolled in COMBI-d as high risk or low risk with respect to survival outcomes and was validated in the COMBI-MB cohort. In COMBI-d, undetectable ctDNA at week 4 was significantly associated with extended progression-free and overall survival, particularly in patients with elevated lactate dehydrogenase concentrations.

Interpretation: Pretreatment and on-treatment BRAFV600-mutant ctDNA measurements could serve as independent, predictive biomarkers of clinical outcome with targeted therapy.

Circulating tumour DNA and melanoma survival: A systematic literature review and meta-analysis.  Gandini, Zanna, De Angelis, et al.  Crit Rev Oncol Hematol.  Jan 2021.

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.

The Prognostic Impact of Circulating Tumour DNA in Melanoma Patients Treated with Systemic Therapies-Beyond BRAF Mutant Detection.  Marsavela, Johansson, Pereira, et al.  Cancers (Basel).  Dec 2020.

In this study, we evaluated the predictive value of circulating tumour DNA (ctDNA) to inform therapeutic outcomes in metastatic melanoma patients receiving systemic therapies. We analyzed 142 plasma samples from metastatic melanoma patients prior to commencement of systemic therapy: 70 were treated with BRAF/MEK inhibitors and 72 with immunotherapies. Patient-specific droplet digital polymerase chain reaction assays were designed for ctDNA detection. Plasma ctDNA was detected in 56% of patients prior to first-line anti-PD1 and/or anti-CTLA-4 treatment. The detection rate in the immunotherapy cohort was comparably lower than those with BRAF inhibitors (76%). Decreasing ctDNA levels within 12 weeks of treatment was strongly concordant with treatment response and predictive of longer progression free survival. Notably, a slower kinetic of ctDNA decline was observed in patients treated with immunotherapy compared to those on BRAF/MEK inhibitors. Whole exome sequencing of ctDNA was also conducted in 9 patients commencing anti-PD-1 therapy to derive tumour mutational burden (TMB) and neoepitope load measurements. The results showed a trend of high TMB and neoepitope load in responders compared to non-responders. Overall, our data suggest that changes in ctDNA can serve as an early indicator of outcomes in metastatic melanoma patients treated with systemic therapies and therefore may serve as a tool to guide treatment decisions.

Yep!  THAT LAST SENTENCE!!!

Prognostic Value of ctDNA Mutation in Melanoma: A Meta-Analysis.  Zheng, Sun, Cong, et al.  J Oncol.. May 2021.

Purpose: Melanoma is the most aggressive form of skin cancer. Circulating tumor DNA (ctDNA) is a diagnostic and prognostic marker of melanoma. However, whether ctDNA mutations can independently predict survival remains controversial. This meta-analysis assessed the prognostic value of the presence or change in ctDNA mutations in melanoma patients.

Methods: We identified studies from the PubMed, EMBASE, Web of Science, and Cochrane databases. We estimated the combined hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) using either fixed-effect or random-effect models based on heterogeneity.

Results: Sixteen studies including 1,781 patients were included. Both baseline and posttreatment detectable ctDNA were associated with poor OS. For PFS, baseline detectable ctDNA may be associated with adverse PFS and baseline high ctDNA and increased ctDNA were significantly associated with adverse PFS. The baseline BRAFV600 ctDNA mutation-positive group was significantly associated with adverse OS compared with the baseline ctDNA-negative group. There were no significant differences in PFS between the baseline BRAFV600 ctDNA mutation-detectable group and the undetectable group.

Conclusion: The presence or elevation of ctDNA mutation or BRAFV600 ctDNA mutation was significantly associated with worse prognosis in melanoma patients.

Liquid biopsy and radiological response predict outcomes following discontinuation of targeted therapy in patients with BRAF mutated melanoma. Di Guardo, Randon, Corti, et al.  Oncologist. August 2021.

Background: Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity after sustained response are unknown.

Patients and methods: This retrospective case series analysis conducted at a single Cancer Center in Italy included patients with BRAF mutated metastatic melanoma treated with a BRAF inhibitor as a single agent or in combination with a MEK inhibitor between June 1, 2011 and January 1, 2020 and interrupting treatment after achieving complete response (CR) or long-lasting partial response (PR - i.e. greater than 12 months) due to cumulative toxicity.

Results: We included 24 patients with a median treatment duration of 59.4 months. CR and PR were achieved in 71% and 29% of patients, respectively. At a median follow-up after treatment discontinuation of 37.8 months, 12-months progression free survival after discontinuation (dPFS) rate was 70.8% and 24-months dPFS rate was 58.3%. Baseline patients and tumor characteristics as well as treatment duration and best response did not significantly impact on dPFS. Patients with CR and negative circulating tumor DNA (ctDNA) at time of discontinuation had a significantly improved dPFS compared to patients with either radiological residual disease or ctDNA positivity. No patient in CR with undetectable ctDNA experienced progression.

Conclusion: The risk of progression is high even in patients with sustained sensitivity to BRAF/MEK inhibitors. Integration of liquid biopsy in clinical trials investigating optimal management of patients with sustained sensitivity to BRAF/MEK inhibitors is warranted.

Implications for practice: Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity are unknown. We analyzed patients with sustained responses (median treatment duration 59.4 months). Twelve and 24-months progression free survival following discontinuation were 70.8% and 58.3% respectively. Complete response and negative ctDNA at time of discontinuation are promising prognostic biomarkers in this setting.

Detection of clinical progression through plasma ctDNA in metastatic melanoma patients: a comparison to radiological progression.  Marsavela, McEvoy, Pereira, et al.  Br J Cancer.  August 2021.

Background: The validity of circulating tumour DNA (ctDNA) as an indicator of disease progression compared to medical imaging in patients with metastatic melanoma requires detailed evaluation.

Methods: Here, we carried out a retrospective ctDNA analysis of 108 plasma samples collected at the time of disease progression. We also analysed a validation cohort of 66 metastatic melanoma patients monitored prospectively after response to systemic therapy.

Results: ctDNA was detected in 62% of patients at the time of disease progression. For 67 patients that responded to treatment, the mean ctDNA level at progressive disease was significantly higher than at the time of response. However, only 30 of these 67 (45%) patients had a statistically significant increase in ctDNA by Poisson test. A validation cohort of 66 metastatic melanoma patients monitored prospectively indicated a 56% detection rate of ctDNA at progression, with only two cases showing increased ctDNA prior to radiological progression. Finally, a correlation between ctDNA levels and metabolic tumour burden was only observed in treatment naïve patients but not at the time of progression in a subgroup of patients failing BRAF inhibition (N = 15).

Conclusions: These results highlight the low efficacy of ctDNA to detect disease progression in melanoma when compared mainly to standard positron emission tomography imaging.

I think the vast preponderance of the evidence shows that knowing the presence of and/or quantity of bits of melanoma floating in your blood stream gives the patient and their physician important information that can impact treatment choice.  That same data can help make decisions about whether or not to stop or change treatments.  Many studies have demonstrated that this simple blood draw can tell you your status weeks to months sooner than tumors can be seen on radiographic studies.  The last study above stands in contrast to that but I try to be complete.  I will say that it is important to note that the study above was a retrospective review of 108 blood samples collected at the time of disease progression vs 66 patients monitored after response to systemic therapy.  I don't think that is the best way to collect and compare data - maybe that's just me.  I leave you with this ~

The prognostic value of circulating tumor DNA in patients with melanoma: A systematic review and meta-analysis.  Feng, Cen, Tan, et al.  Transl Oncol.  June 2021.

Background: Circulating tumor DNA (ctDNA) has been investigated as a potential prognostic biomarker to evaluate the therapeutic efficacy and disease progression in melanoma patients, yet results remain inconclusive. The purpose of this study was to illustrate the prognostic value of ctDNA in melanoma.

Objectives: To describe the clinical prognostic value of ctDNA for melanoma patients.

Methods: Searched for eligible articles from Pubmed, Web of Science and Embase. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the association between ctDNA at baseline or during treatment and overall survival (OS) and progression-free survival (PFS).

Results: A total of 9 articles were obtained, involving 617 melanoma patients. The pooled HRs revealed that compared with baseline undetectable ctDNA patients, detectable ctDNA was highly correlated with poor OS and PFS. A meta-analysis of these adjusted HRs was performed and confirmed that ctDNA collected at baseline was associated with poorer OS/PFS. During treatment, a significant association was shown between ctDNA and poorer OS/PFS.

Conclusion: Investigation and application of ctDNA will improve "liquid biopsy" and play a role in early prediction, monitoring disease progression and precise adjusting treatment strategies in melanoma patients.

For me, I think ctDNA can provide valuable information that we can use when having to make the incredibly difficult decisions faced by cancer patients.  Coming soon - putting my money and my blood - where my mouth is. Hang tough. - c 

Circulating DNA (ctDNA) Yes, again! A noninvasive method of diagnosing and monitoring melanoma patients

Yep.  Another thing I have been yelling about for years.  Circulating tumor DNA.  Something we can measure in the blood of melanoma patients.  Here are zillions of reports:  Important stuff floating in our blood - tumor DNA, micro RNA, cytokines - can determine tumor burden, predict response, and side effects for melanoma patients!!!  Now, there's this:

ctDNA as a noninvasive monitoring tool in metastatic melanoma.  2019 ASCO.  Varaljai, Wistuba-Hamprecht, Seremet, et al.  J Clin Oncology 37, 2019.

Background: The field of liquid biopsy provides a promising alternative to standard tissue biopsies. Previous work has shown that plasma circulating cell-free DNA (ctDNA) can reflect the heterogeneous spectrum of mutations in cancer including metastatic melanoma. Our project aimed to establish and statistically validate plasma-based assays for tumour load and therapy monitoring in melanoma. Methods: On a large cohort of stage III and stage IV melanoma patients (N = 96) who received signalling targeted or immune checkpoint inhibitors we showed that the most common oncogenic drivers of this disease such as the BRAFV600E, NRASQ61 and the TERTC250T and TERTC228T promoter mutations (termed TERTprom) can be analysed in ctDNA with highly sensitive droplet digital PCR technology (detection of mutant ctDNA down to 0.01% analytical sensitivity). Results: Our research has demonstrated that ctDNA (irrespective of the genotype) significantly correlates with tumour stage. Using receiver operating characteristics (ROC) analyses thresholds were established for risk stratification and response prediction. Elevated ctDNA at baseline was a significant predictor of disease progression compared to elevated LDH or S100 in multivariable cox proportional hazards model. During therapy, patients with low ctDNA load (below the ROC threshold) had significantly better radiological outcomes and prolonged progression free survival (PFS) compared to patients with high ctDNA load. Our findings were confirmed on an independent cohort of metastatic melanoma patients (N = 35) treated with immune checkpoint inhibitors, where also during therapy low ctDNA load correlated with prolonged PFS. An added benefit of ctDNA was demonstrated in about 80% of the patients, where ctDNA analyses preceded the radiological diagnosis of response or relapse. Progression was detected in plasma ctDNA in average 3.5 months earlier as compared to routine imaging techniques. Finally, we demonstrated that the occurrence of NRASQ61 mutation in BRAFV600-inhibitor treated patients at therapy baseline was associated with treatment failure. The sub-clonal NRASQ61 mutation at therapy baseline was an independent predictor of shorter PFS as compared to BRAFV600E patients without the NRASQ61 mutation at therapy baseline. Conclusions: In sum, our results support the value of ctDNA as a sensitive biomarker for real-time therapy monitoring and early detection of disease progression.

It works!  Doesn't require surgical biopsy.  Shows results months sooner than radiological imaging techniques and doesn't expose the patient to radiation.  What are we waiting on??????

There is also, this:

Circulating Cell-Free DNA-Diagnostic and Prognostic Applications in Personalized Cancer Therapy.  Oellerich, Schutz, Beck, Walson.  Ther Drug Monit. 2019 Apr.

Genomic analyses in oncologic care allow for the development of more precise clinical laboratory tests that will be critical for personalized pharmacotherapy. Traditional biopsy-based approaches are limited by the availability of sequential tissue specimens to detect resistance. Blood-based genomic profiling ("liquid biopsy") is useful for longitudinal monitoring of tumor genomes and can complement biopsies. Tumor-associated mutations can be identified in cell-free tumor DNA (ctDNA) from patient blood samples and used for monitoring disease activity. The US Food and Drug Administration approved a liquid biopsy test for EGFR-activating mutations in patients with non-small-cell lung cancer as a companion diagnostic for therapy selection. ctDNA also allows for the identification of mutations selected by treatment such as EGFR T790M in non-small-cell lung cancer. ctDNA can also detect mutations such as KRAS G12V in colorectal cancer and BRAF V600E/V600K in melanoma. Chromosomal aberration pattern analysis by low-coverage whole genome sequencing is a new, broader approach. Genomic imbalances detected in cell-free DNA (cfDNA) can be used to compute a copy number instability (CNI) score. In clinical studies, it was demonstrated that the change in CNI score can serve as an early predictor of therapeutic response to chemotherapy/immunotherapy of many cancer types. In multivariable models, it could be shown that the CNI score was superior to clinical parameters for prediction of overall survival in patients with head and neck cancer. There is emerging evidence for the clinical validity of ctDNA testing regarding identification of candidates for targeted therapies, prediction of therapeutic response, early detection of recurrence, resistance mutation detection, measuring genetic heterogeneity, tumor burden monitoring, and risk stratification. Improvement of sensitivity to detect tumors at very early stages is difficult due to insufficient mutant DNA fraction of less than/= to 0.01%. Further developments will include validation in prospective multicenter interventional outcome studies and the development of digital platforms to integrate diagnostic data.

The technology exists to make this simple test available - impacting melanoma patients in lots of ways!  Let's make it so!!!

And, yes.  There is still beauty -

 - despite the storm.  ~ les