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