BRAFV600-mutant Melanoma Research Articles

1117P Overall survival (OS) in patients with metastatic BRAF V600-mutant melanoma treated with encorafenib plus binimetinib (ENCO+BINI): Comparing real-world vs clinical trial data

1117P Overall survival (OS) in patients with metastatic BRAF V600-mutant melanoma treated with encorafenib plus binimetinib (ENCO+BINI): Comparing real-world vs clinical trial data

BRAF/MEK Inhibition as a Bridge to Immunotherapy for Symptomatic BRAF V600 Melanoma Brain Metastases: A Case Series.

Targeted and immune therapies have changed the paradigm of treatment for patients with metastatic melanoma. Treatment of patients with symptomatic melanoma brain metastases, however, is complicated by the frequent use of immune suppression for the management of vasogenic edema and the urgency in addressing disease burden. Use of BRAF/MEK inhibitors in patients with a corresponding BRAF V600 mutation often results in rapid response but is hindered by high rates of disease relapse and progression. Immunotherapy has higher durability of response, but the rate of response is slower and responses can be significantly diminished for patients on concurrent steroid therapy. Considering this gap in evidence-based guidance for optimal adjuvant therapy sequence in immunosuppressed patients with BRAF V600-mutant melanoma brain metastases, we report on 4 cases utilizing BRAF/MEK inhibitors as a bridging therapy for brain metastases management before initiation of immune checkpoint inhibitor therapy. Future prospective studies will be required to determine the optimal treatment sequencing for patients in this population with high unmet medical need.

1114P Encorafenib (E) plus binimetinib (B) in unresectable advanced or metastatic BRAFV600-mut melanoma, real-world evidence in Spain (GEM 2002 - BECARE)

1114P Encorafenib (E) plus binimetinib (B) in unresectable advanced or metastatic BRAFV600-mut melanoma, real-world evidence in Spain (GEM 2002 - BECARE)

Treatment management for BRAF-mutant melanoma patients with tumor recurrence on adjuvant therapy: a multicenter study from the prospective skin cancer registry ADOREG

BackgroundAdjuvant therapy with immune-checkpoint inhibitors (CPI) or BRAF/MEK-directed targeted therapy (TT) improves recurrence-free survival (RFS) for patients with advanced, BRAFV600-mutant (BRAFmut) resected melanoma. However, 40% of these patients will develop...

Ezrin Inhibition Overcomes Acquired Resistance to Vemurafenib in BRAFV600E-Mutated Colon Cancer and Melanoma Cells In Vitro.

Despite the advancements in targeted therapy for BRAFV600E-mutated metastatic colorectal cancer (mCRC), the development of resistance to BRAFV600E inhibition limits the response rate and durability of the treatment. Better understanding of the resistance mechanisms to BRAF inhibitors will facilitate the design of novel pharmacological strategies for BRAF-mutated mCRC. The aim of this study was to identify novel protein candidates involved in acquired resistance to BRAFV600E inhibitor vemurafenib in BRAFV600E-mutated colon cancer cells using an integrated proteomics approach. Bioinformatic analysis of obtained proteomics data indicated actin-cytoskeleton linker protein ezrin as a highly ranked protein significantly associated with vemurafenib resistance whose overexpression in the resistant cells was additionally confirmed at the gene and protein level. Ezrin inhibition by NSC305787 increased anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant cells in an additive manner, which was accompanied by downregulation of CD44 expression and inhibition of AKT/c-Myc activities. We also detected an increased ezrin expression in vemurafenib-resistant melanoma cells harbouring the BRAFV600E mutation. Importantly, ezrin inhibition potentiated anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant melanoma cells in a synergistic manner. Altogether, our study suggests a role of ezrin in acquired resistance to vemurafenib in colon cancer and melanoma cells carrying the BRAFV600E mutation and supports further pre-clinical and clinical studies to explore the benefits of combined BRAF inhibitors and actin-targeting drugs as a potential therapeutic approach for BRAFV600E-mutated cancers.

Treatment experience with encorafenib plus binimetinib for BRAF V600-mutant metastatic melanoma: management insights for clinical practice.

For patients with locally advanced or metastatic melanoma who have BRAF V600 activating mutations, combination therapy with BRAF and MEK inhibitors is now the standard of care. The combination of encorafenib, a highly selective adenosine triphosphate-competitive BRAF inhibitor, plus binimetinib, a potent, selective, allosteric, non-adenosine triphosphate-competitive MEK1/2 inhibitor, was approved by the US Food and Drug Administration for unresectable or metastatic melanoma with BRAF V600E or V600K mutations based on data from the phase III COLUMBUS study (NCT01909453). Clinical data evaluating BRAF and MEK inhibitor combinations in advanced melanoma indicate a specific profile of adverse events that includes serious retinopathy, skin disorders, and cardiovascular toxicities. Here we provide an overview of the rationale for combining BRAF and MEK inhibitors for the treatment of melanoma, long-term safety results from COLUMBUS, and guidance on managing the most common adverse events associated with this combination based on clinical experience. Proactive and appropriate management of adverse events can allow for longer treatment durations and may result in better treatment outcomes.

Single cell profiling of tumour biopsies and heterogeneity in response of dedifferentiated melanoma.

64 Background: Patients with advanced BRAFV600-mutant melanoma can be treated with immune checkpoint inhibitors or combination BRAF/MEK inhibitors. The sequence of these therapies can influence response to second-line treatment. Patients who progress on first-line PD1 blockade have poorer outcomes on BRAF/MEK inhibitors compared to patients who are treatment-naïve. Thus, defining the molecular features that are modified by therapy and that influence subsequent treatment responses require thorough characterization. Methods: In this study, tumor biopsies from five BRAF-mutant melanoma patients progressing on anti-PD1 (PROG) and five BRAF-mutant treatment-naïve (NAÏVE) patients were dissociated and treated ex vivo with BRAF/MEK inhibitors (dabrafenib+trametinib (DT)) before flow cytometry profiling and single cell transcriptome sequencing. Results: DT treatment did not alter tumor or immune cell proportions but effectively inhibited MAPK signaling by decreasing phosphorylated S6 levels in tumor cells within 8/10 melanoma samples. Single cell RNA-sequencing of the tumor dissociates identified four distinct melanoma differentiation states (e.g. melanocytic, transitory, neural crest-like and undifferentiated). The proportions of these cell states differed between tumor specimens, and were not affected by DT treatment. The neural crest-like and undifferentiated melanoma cells were enriched in PROG compared to NAIVE tumor samples and all differentiation states responded, albeit variably. For instance, MAPK inhibition after DT treatment was less pronounced in undifferentiated melanoma cells. Importantly, within the undifferentiated cell state, we identified a proportion of melanoma cells capable of responding to DT, and comparison of responding vs non-responding undifferentiated cells showed enrichment of pro-inflammatory IL-6 and TNFα signaling in the non-responding population. Elevated IL-6 and TNFα pathway activity correlated with decreased potency to MAPK inhibition, indicating that increased IL-6 and TNFα signaling in undifferentiated melanoma may contribute to resistance to MAPK inhibition. Conclusions: Ex vivo treatment of tumor dissociates coupled with single cell transcriptome sequencing identified cell state-specific responses to MAPK inhibition. Resistance to MAPK inhibition may be driven, in part, by tumor-intrinsic pro-inflammatory IL-6 and TNFα signalling.

Contribution of MEK Inhibition to BRAF/MEK Inhibitor Combination Treatment of BRAF-Mutant Melanoma: Part 2 of the Randomized, Open-Label, Phase III COLUMBUS Trial.

In COLUMBUS part 1, patients with advanced BRAFV600-mutant melanoma were randomly assigned 1:1:1 to encorafenib 450 mg once daily plus binimetinib 45 mg twice a day (COMBO450), vemurafenib 960 mg twice a day, or encorafenib 300 mg once daily (ENCO300). As previously reported, COMBO450 improved progression-free survival (PFS) versus vemurafenib (part 1 primary end point) and ENCO300 (part 1 key secondary end point; not statistically significant). Part 2, requested by the US Food and Drug Administration, evaluated the contribution of binimetinib by maintaining the same encorafenib dosage in the combination (encorafenib 300 mg once daily plus binimetinib 45 mg twice daily [COMBO300]) and ENCO300 arms. In part 2, patients were randomly assigned 3:1 to COMBO300 or ENCO300. ENCO300 (parts 1 and 2) data were combined, per protocol, for PFS analysis (key secondary end point) by a blinded independent review committee (BIRC). Other analyses included overall response rate (ORR), overall survival, and safety. Two hundred fifty-eight patients received COMBO300, and 86 received ENCO300. Per protocol, ENCO300 arms (parts 1 and 2 combined) were also evaluated (n = 280). The median follow-up for ENCO300 was 40.8 months (part 1) and 57.1 months (part 2). The median PFS (95% CI) was 12.9 months (10.9 to 14.9) for COMBO300 versus 9.2 months (7.4 to 11.1) for ENCO300 (parts 1 and 2) and 7.4 months (5.6 to 9.2) for ENCO300 (part 2). The hazard ratio (95% CI) for COMBO300 was 0.74 (0.60 to 0.92; two-sided P = .003) versus ENCO300 (parts 1 and 2). The ORR by BIRC (95% CI) was 68% (62 to 74) and 51% (45 to 57) for COMBO300 and ENCO300 (parts 1 and 2), respectively. COMBO300 had greater relative dose intensity and fewer grade 3/4 adverse events than ENCO300. COMBO300 improved PFS, ORR, and tolerability compared with ENCO300, confirming the contribution of binimetinib to efficacy and safety.

Evolving Acquired Vemurafenib Resistance in a BRAF V600E Mutant Melanoma PDTX Model to Reveal New Potential Targets.

Malignant melanoma is challenging to treat, and metastatic cases need chemotherapy strategies. Targeted inhibition of commonly mutant BRAF V600E by inhibitors is efficient but eventually leads to resistance and progression in the vast majority of cases. Numerous studies investigated the mechanisms of resistance in melanoma cell lines, and an increasing number of in vivo or clinical data are accumulating. In most cases, bypassing BRAF and resulting reactivation of the MAPK signaling, as well as alternative PI3K-AKT signaling activation are reported. However, several unique changes were also shown. We developed and used a patient-derived tumor xenograft (PDTX) model to screen resistance evolution in mice in vivo, maintaining tumor heterogeneity. Our results showed no substantial activation of the canonical pathways; however, RNAseq and qPCR data revealed several altered genes, such as GPR39, CD27, SLC15A3, IFI27, PDGFA, and ABCB1. Surprisingly, p53 activity, leading to apoptotic cell death, was unchanged. The found biomarkers can confer resistance in a subset of melanoma patients via immune modulation, microenvironment changes, or drug elimination. Our resistance model can be further used in testing specific inhibitors that could be used in future drug development, and combination therapy testing that can overcome inhibitor resistance in melanoma.

USP18 enhances the resistance of BRAF-mutated melanoma cells to vemurafenib by stabilizing cGAS expression to induce cell autophagy

This study aims to discern the possible molecular mechanism of the effect of ubiquitin-specific peptidase 18 (USP18) on the resistance to BRAF inhibitor vemurafenib in BRAF V600E mutant melanoma by regulating cyclic GMP-AMP synthase (cGAS). The cancer tissues of BRAF V600E mutant melanoma patients before and after vemurafenib treatment were collected, in which the protein expression of USP18 and cGAS was determined. A BRAF V600E mutant human melanoma cell line (A2058R) resistant to vemurafenib was constructed with its viability, apoptosis, and autophagy detected following overexpression and depletion assays of USP18 and cGAS. Xenografted tumors were transplanted into nude mice for in vivo validation. Bioinformatics analysis showed that the expression of cGAS was positively correlated with USP18 in melanoma, and USP18 was highly expressed in melanoma. The expression of cGAS and USP18 was up-regulated in cancer tissues of vemurafenib-resistant patients with BRAF V600E mutant melanoma. Knockdown of cGAS inhibited the resistance to vemurafenib in A2058R cells and the protective autophagy induced by vemurafenib in vitro. USP18 could deubiquitinate cGAS to promote its protein stability. In vivo experimentations confirmed that USP18 promoted vemurafenib-induced protective autophagy by stabilizing cGAS protein, which promoted resistance to vemurafenib in BRAF V600E mutant melanoma cells. Collectively, USP18 stabilizes cGAS protein expression through deubiquitination and induces autophagy of melanoma cells, thereby promoting the resistance to vemurafenib in BRAF V600E mutant melanoma.

Atezolizumab, vemurafenib, and cobimetinib in patients with melanoma with CNS metastases (TRICOTEL): a multicentre, open-label, single-arm, phase 2 study

Targeted therapy and immunotherapy have shown intracranial activity in melanoma with CNS metastases, but there remains an unmet need, particularly for patients with symptomatic CNS metastases. We aimed to evaluate atezolizumab in combination with cobimetinib or vemurafenib plus cobimetinib in patients with melanoma with CNS metastases. TRICOTEL was a multicentre, open-label, single-arm, phase 2 study done in two cohorts: a BRAFV600 wild-type cohort and a BRAFV600 mutation-positive cohort, recruited at 21 hospitals and oncology centres in Brazil, France, Germany, Hungary, Italy, Spain, and Switzerland. Eligible patients were aged 18 years or older with previously untreated metastatic melanoma, brain metastases of 5 mm or larger in at least one dimension, and an Eastern Cooperative Oncology Group performance status of 2 or less. Patients in the BRAFV600 wild-type cohort received intravenous atezolizumab (840 mg, days 1 and 15 of each 28-day cycle) plus oral cobimetinib (60 mg once daily, days 1-21). Patients in the BRAFV600 mutation-positive cohort received intravenous atezolizumab (840 mg, days 1 and 15 of each 28-day cycle) plus oral vemurafenib (720 mg twice daily) plus oral cobimetinib (60 mg once daily, days 1-21); atezolizumab was withheld in cycle 1. Treatment was continued until progression, toxicity, or death. The primary outcome was intracranial objective response rate confirmed by assessments at least 4 weeks apart, as assessed by independent review committee (IRC) using modified Response Evaluation Criteria in Solid Tumours version 1.1. Because of early closure of the BRAFV600 wild-type cohort, the primary endpoint of intracranial objective response rate by IRC assessment was not done in this cohort; intracranial objective response rate by investigator assessment was reported instead. Efficacy and safety were analysed in all patients who received at least one dose of study medication. This trial is closed to enrolment and is registered with ClinicalTrials.gov, NCT03625141. Between Dec 13, 2018, and Dec 7, 2020, 65 patients were enrolled in the BRAFV600 mutation-positive cohort; the BRAFV600 wild-type cohort was closed early after enrolment of 15 patients. Median follow-up was 9·7 months (IQR 6·3-15·0) for the BRAFV600 mutation-positive cohort and 6·2 months (3·5-23·0) for the BRAFV600 wild-type cohort. Intracranial objective response rate was 42% (95% CI 29-54) by IRC assessment in the BRAFV600 mutation-positive cohort and 27% (95% CI 8-55) by investigator assessment in the BRAFV600 wild-type cohort. Treatment-related grade 3 or worse adverse events occurred in 41 (68%) of 60 patients who received atezolizumab plus vemurafenib plus cobimetinib in the BRAFV600 mutation-positive cohort, the most common of which were lipase increased (15 [25%] of 60 patients) and blood creatine phosphokinase increased (11 [18%]). Eight (53%) of 15 patients treated with atezolizumab plus cobimetinib in the BRAFV600 wild-type cohort had treatment-related grade 3 or worse adverse events, most commonly anaemia (two [13%]) and dermatitis acneiform (two [13%]). Treatment-related serious adverse events occurred in 14 (23%) of 60 patients who received triplet therapy in the BRAFV600 mutation-positive cohort and two (13%) of 15 in the BRAFV600 wild-type cohort. No treatment-related deaths occurred. Atezolizumab plus vemurafenib and cobimetinib provided intracranial activity in patients with BRAFV600-mutated melanoma with CNS metastases. F Hoffmann-La Roche.

Cost-effectiveness of encorafenib with binimetinib in unresectable or metastatic BRAF-mutant melanoma.

The objective of this study was to determine the cost-effectiveness of encorafenib with binimetinib (EncoBini) as compared to other targeted double combination therapies, namely dabrafenib with trametinib (DabraTrame) and vemurafenib with cobimetinib (VemuCobi), for the treatment of BRAF V600-mutant unresectable or metastatic melanoma (MM) from the French payer perspective. A partitioned survival model was developed considering a lifetime horizon. The model structure simulated the clinical pathway of patients with BRAF V600-mutant MM. Clinical effectiveness and safety inputs were sourced from the COLUMBUS trial, a network meta-analysis and published literature. Costs, resource use, and the quality of life inputs were obtained from the literature and appropriate French sources. Over a lifetime horizon, EncoBini was associated, on average, with reduced costs and increased quality adjusted life years (QALYs), dominating both targeted double combination therapies. For a willingness-to-pay threshold of €90,000 per QALY, the probability of EncoBini being cost-effective against either comparator remained above 80%. The most influential model parameters were the hazard ratios for the overall survival of EncoBini vs DabraTrame and VemuCobi, the pre- and post-progression utility values, as well as treatment dosages and the relative dose intensity of all interventions. EncoBini is associated with reduced costs and increased QALYs, dominating other targeted double combination therapies (DabraTrame, VemuCobi) for patients with BRAF V600-mutant MM in France. EncoBini is a highly cost-effective intervention in MM.

Outcomes in patients with BRAFV600-mutated melanoma and brain metastases at baseline treated with dabrafenib plus trametinib.

Brain metastases (BM) and lactate dehydrogenase (LDH) levels above the upper limit of normal (ULN) are associated with poor prognosis in patients with melanoma. Although treatment with the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib have demonstrated long-term clinical benefit in patients with melanoma, data on their efficacy in patients with BM are limited. DESCRIBE Italy is an observational, retrospective, real-world study evaluating dabrafenib plus trametinib in 499 patients with BRAFV600-mutant stage III unresectable or stage IV melanoma from various sites across Italy. Here, we analyzed the clinical outcomes for the subgroup of patients receiving first-line treatment and presenting with BM at diagnosis and assessed the impact of predictive factors such as LDH levels and the presence of other metastases on median progression-free survival (mPFS). Overall, 325 evaluable patients were on first-line therapy and are the focus of this analysis; of these, 76 patients (23.4%) had BM at baseline. mPFS was lower for patients with BM at baseline compared with overall patients (8.7 months vs 9.3 months, respectively). Patients with BM at diagnosis and LDH >ULN had a considerably shorter mPFS compared with patients with LDH ⩽ULN (5.3 months vs 9.9 months, respectively). mPFS was noticeably longer for patients with cerebral metastases only compared with patients with cerebral and other metastases (15.0 months vs 8.7 months, respectively). Dabrafenib plus trametinib showed effectiveness in a real-world population of patients with advanced BRAFV600-mutated melanoma and BM at baseline, supporting its use in this population with poor outcomes.

IMPemBra: a phase 2 study comparing pembrolizumab with intermittent/short-term dual MAPK pathway inhibition plus pembrolizumab in patients with melanoma harboring the BRAFV600 mutation

BackgroundContinuous combination of MAPK pathway inhibition (MAPKi) and anti-programmed death-(ligand) 1 (PD-(L)1) showed high response rates, but only limited improvement in progression-free survival (PFS) at the cost of a high...

Early switch from run-in treatment with vemurafenib plus cobimetinib to atezolizumab after 3 months leads to rapid loss of tumour control in patients with advanced BRAFV600-positive melanoma: The ImmunoCobiVem phase 2 randomised trial

AimImmunoCobiVem investigated whether a planned switch to atezolizumab after achieving tumour control during run-in with vemurafenib + cobimetinib improves progression-free survival (PFS) and overall survival (OS) compared to continuous targeted therapy (TT) in patients with previously untreated advanced BRAFV600-mutated melanoma. MethodsIn this multicenter phase 2 study, patients received vemurafenib plus cobimetinib. After 3months, patients without progressive disease (PD) were randomly assigned (1:1) to continue vemurafenib + cobimetinib (Arm A) or switch to atezolizumab (Arm B) until first documented PD (PD1). Primary outcome was PFS1 (time from start of run-in until PD1 or death). OS and safety were also assessed. ResultsOf 185 patients enroled between November 2016 and December 2019, 135 were randomly assigned after the run-in period (Arm A, n = 69; Arm B, n = 66). Median PFS1 was significantly longer in Arm A versus Arm B (13.9 versus 5.9months; hazard ratio [HR] 0.55; 95% confidence interval [CI], 0.37–0.84; PStratified=0.001). Median OS was not reached in either arm (HR 1.22; 95%CI, 0.69–2.16; PStratified=0.389); 2-year OS was higher in Arm B versus Arm A (67%; 95%CI, 53–78 versus 58%; 95%CI, 45–70). Grade 3/4 AEs occurred in 55% of patients in Arm A and 64% in Arm B; treatment-related AEs led to discontinuation of any drug in 7% and 9% of patients, respectively. ConclusionIn patients with BRAFV600-mutated advanced melanoma who achieve tumour control with TT, early switch at 3months to atezolizumab led to rapid loss of tumour control but provided a numerical OS benefit at 2years compared with continued TT.

A phase 1/2 study of CFT1946, a novel, bifunctional degradation activating compound (BIDAC) degrader, of mutant BRAF V600 as monotherapy and in combination with trametinib, in mutant BRAF V600 solid tumors.

TPS3163 Background: BRAF is a protein kinase that acts as a signal transducer in the MAPK pathway. Mutant BRAF V600 is capable of uncontrolled signaling and is constitutively active and signals as a monomer, leading to hyperactivation of MEK, ERK, and dysregulation of cellular proliferation. Mutant BRAF V600 is a clinically-validated target in a variety of cancers including melanoma, colorectal cancer (CRC), non-small cell lung cancer (NSCLC), and anaplastic thyroid carcinoma (ATC). Currently approved BRAF inhibitors (BRAFi) result in paradoxical RAF activation as the mutant BRAF protein is still able to dimerize with WT BRAF, resulting in a dimeric signaling complex. CFT1946 is a novel, orally bioavailable BiDAC degrader that inhibits and degrades mutant BRAF V600 protein. Distinct from approved BRAFi, CFT1946 avoids paradoxical RAF activation as the degraded BRAF V600 mutant protein can no longer incorporate into a dimeric signaling complex. CFT1946 is selective for the mutant protein and spares WT BRAF V600. CFT1946 has demonstrated preclinical activity in BRAF V600 mutant in vitro and in vivo models, including models resistant to BRAFi. These preclinical data provide rationale for a first-in-human (FIH) study to evaluate CFT1946 in BRAF V600 mutant solid tumors. Methods: This is a FIH, open-label, multicenter, Phase 1/2 clinical trial to characterize the initial safety, tolerability, and preliminary efficacy of CFT1946 and CFT1946+trametinib in BRAF V600 mutant melanoma, NSCLC, CRC, ATC, and other non-CNS BRAF V600 mutant solid tumors. This study includes 2 phases: dose escalation Phase 1 comprising CFT1946 (Arm A) with a starting oral dose of 20 mg twice daily and CFT1946+trametinib (Arm B) as well as dose expansion Phase 2 comprising CFT1946 (Arm A1) and CFT1946+trametinib (Arms B1 and B2). Arm A1 and B1 will include BRAF V600 mutant melanoma and NSCLC with prior BRAFi therapy while Arm B2 will enroll BRAF V600 mutant NSCLC who are BRAFi-naïve. Phase 2 will be initiated once the RP2D has been identified. Eligible subjects are ≥18yo with documented BRAF V600 mutant cancers who have received ≥1 prior therapy. CFT1946 will be administered orally in 28-day cycles until disease progression or intolerable toxicity. Primary objectives include safety, tolerability, RP2D and preliminary antitumor activity of CFT1946 monotherapy and in combination with trametinib. Secondary objectives include assessment of pharmacokinetics and pharmacodynamics. Key inclusion criteria include documented evidence of a BRAF V600 mutation obtained from tumor tissue or liquid biopsy; at least 1 prior line of standard-of-care therapy for locally advanced or metastatic disease. The study is anticipated to enroll 101-122 patients across 11 participating US and European sites and is currently open to enrollment (NCT05668585). Clinical trial information: NCT05668585 .

A phase 1, open-label, dose escalation and dose expansion study to evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of PF-07799933 (ARRY-440) as a single agent and in combination therapy in participants 16 years and older with advanced solid tumors with BRAF alterations.

TPS3164 Background: Approved BRAF inhibitors (BRAFi) are inactive against RAF dimers. Accordingly, the acquisition of BRAF dimers ( e.g., through drug-acquired splice variants or BRAF amplification) may lead to therapy resistance. Non-V600 (class II and III) BRAF alterations that occur de novo in diverse tumor types also signal as dimers and therefore have no approved targeted therapeutic options. Additional liabilities of approved BRAFi include toxicity from paradoxical activation of wild-type (WT) RAF and limited brain penetration, a common primary and metastatic site for BRAF-altered cancers. In contrast to approved agents, investigational BRAFi inhibit WT and mutant RAF proteins (A, B, and C-RAF, monomers, dimers), and therefore may be limited by on-target toxicity from “pan-RAF” inhibition. PF-07799933 is an oral selective ATP-competitive small-molecule RAF kinase inhibitor that suppresses BRAF signaling in BRAF V600-mutant and non-V600- BRAF mutant tumors. It displays significantly less paradoxical activation than approved BRAFi and is not “pan RAF” as it spares non-BRAF-containing RAF dimers. We describe here the Phase 1 study of PF-07799933 as monotherapy or in combination with binimetinib or cetuximab in participants with BRAF-altered advanced solid tumors. Methods: The purpose of this first-in-human study is to investigate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and potential clinical benefits of PF-07799933 administered as a single agent and in combination in participants with BRAF Class I, II and III mutated solid tumors with or without brain involvement. Part 1 (monotherapy dose escalation) and Part 2 (combination dose escalation) will enroll participants with BRAF V600 mutation who have progressed on a approved BRAFi or with de novo Class II or III alterations who have progressed on standard of care therapy. The primary objective of Part 1 is to determine monotherapy MTD/RDE of PF-07799933. Participants in Part 1 will be allowed to add on rational combination with either binimetinib or cetuximab at the time of disease progression. Once PK measurements indicate the potential for significant BRAF inhibition in the brain, participants with untreated and symptomatic brain metastases will be allowed to enroll. The primary objective of Part 2 is combination MTDc/RDEc of PF-07799933 with binimetinib or cetuximab. The primary objective of Part 3 is efficacy in defined cohorts (total ~120 participants): Cohort 1-2: BRAF V600 mutant melanoma; Cohort 3: BRAF Class II altered melanoma; Cohorts 4-5: BRAF V600 and Class II altered CRC; Cohort 6: other BRAF V600, Class II/III altered solid tumor not qualifying for Cohorts 1-5. Clinical trial information: NCT05355701 .

Encorafenib (enco) + binimetinib (bini) + pembrolizumab (pembro) for unresectable locally advanced or metastatic BRAF V600-mutant melanoma: Results from STARBOARD safety lead-in (SLI).

9531 Background: BRAF inhibitors (BRAFi) + MEK inhibitors (MEKi) (eg, enco + bini) and immune checkpoint inhibitors (CPIs) (eg, pembro) are approved for patients (pts) with BRAF V600-mutant metastatic melanoma. Combinations of BRAFi + MEKi with CPIs further improve outcomes and may offer additional treatment strategies. STARBOARD (NCT04657991) is an ongoing randomized, double-blinded, placebo-controlled, phase 3 study of enco + bini + pembro vs pembro in pts with unresectable locally advanced or metastatic BRAF V600-mutant cutaneous melanoma. Here we present the SLI results. Methods: Key inclusion criteria were histologically confirmed unresectable/metastatic BRAF V600E/K-mutant cutaneous melanoma and ≤1 prior systemic therapy for unresectable/metastatic disease. Pts received enco 450 mg QD + bini 45 mg BID + pembro 200 mg IV Q3W (COMBO450+P) or enco 300 mg QD + bini 45 mg BID + pembro 200 mg IV Q3W (COMBO300+P). The primary objective was to identify the recommended phase 3 dose (RP3D). The primary endpoint was dose-limiting toxicity (DLT) incidence; secondary endpoints included safety, objective response rate (ORR), time to response (TTR), and PFS (post hoc). Results: 20 pts received COMBO450+P and 17 COMBO300+P (cutoff: Dec 2, 2022). See table for baseline characteristics. 1 pt had a DLT with COMBO450+P: Grade (G) 3 drug-induced liver injury with concurrent G4 ALT increase and G3 bilirubin increase that resolved. 2 pts had DLTs with COMBO300+P: 1 with G3 rheumatoid arthritis flare and 1 with inability to receive drug due to G4 arthralgia, G4 back pain, G4 pyrexia, G3 chills, G3 headache, G3 paranesthesia, and G3 maculopapular rash. Drug-related AEs led to permanent discontinuation in 4, 5, and 6 pts for enco, bini, and pembro, respectively. 1 pt in the COMBO300+P arm died <28 days after discontinuing all study treatments due to disease progression. See table for antitumor activity data. Conclusions: Safety across cohorts was comparable and consistent with the known safety profile of each agent. Both regimens were generally tolerable; COMBO450+P was chosen as the RP3D based on the totality of the safety data. The phase 3 portion of STARBOARD is ongoing. Clinical trial information: NCT04657991 . [Table: see text]

Combination of regorafenib with BRAF-/MEK-inhibitors for the treatment of patients with refractory melanoma brain metastases.

e14003 Background: there are no active treatment options available for patients (pts) diagnosed with melanoma brain metastases (MBM) that progress despite treatment with immune checkpoint inhibitors (ICI), and BRAF-/MEK-inhibitors (BRAF/MEKi) in pts with BRAF V600mutant melanoma. Regorafenib (REGO), an oral multi-target kinase inhibitor, including potent inhibition of RAF-dimers, has single-agent activity in pretreated melanoma (AS Vander Mijnsbrugge et al. SMR 2022). Here we report our single-institution experience with REGO in combination with BRAF/MEKi in pts with refractory MBM. Methods: pts were identified prospectively, medical records were reviewed retrospectively. Results: 13 pts with stage IV-M1d melanoma were included (6F, med age 54y [range 33-72], WHO PS: 0/1/2/3 resp. n = 1/4/6/2 pts, BRAF V600mut: n = 9, NRAS Q61mut: n = 4). Pts previously progressed on ICI (anti-PD-1 and -CTLA-4; 13 pts); BRAF-/MEK-inhibitor (all BRAF V600mut pts); chemotherapy (3 pts), T-VEC (2 pts), REGO mono (2 pts), and REGO+ICI (2 pts). At baseline, 11 pts had active MBM (8 pts on corticosteroids); 10 pts had extracranial evaluable disease. Pts were treated with REGO (40-80 mg QD) combined with BRAF/MEKi in 9 BRAF V600mut pts (dabrafenib/trametinib: n = 4; encorafenib/binimetinib: n = 5) or, in 4 NRAS Q61mut pts, with trametinib or binimetinib (+ low-dose BRAF-inhibitor if needed to mitigate skin toxicity). Treatment was stopped in 8 pts because of PD and is ongoing in 5 pts (3-49 wks after initiating therapy). There were no grade 4-5 TRAE. Grade 3 TRAE included: arterial hypertension (n = 4), hepatotoxicity (n = 2), diverticular bleeding (n = 1), and duodenal perforation, treated conservatively (n = 1). None of the 2 pts without active MBM at baseline progressed within the CNS. In 11 response evaluable pts (incl. 10 with evaluable extracranial metastases), best objective intracranial response (according to RANO-BM) was PR in 4 pts (36%; 3 BRAF V600mut pts), and SD in 4 pts (36%; 3 BRAF V600mut pts). Intracranial responses corresponded with extracranial responses in all but 3 pts (1 NRAS Q61mut pt with a PR intra-, had SD extracranially; 1 BRAF V600mut pt and 1 NRAS Q61mut pt with SD intra-, had PD extracranially); considering a potential clinical benefit of therapy beyond first PD, both pts continued treatment and remained clinically stable at the latest FU (resp. 15 and 49 wks after initiating therapy). Median time on REGO+BRAF/MEKi in BRAF V600mut pts was 15.9 wks (range 3-46), and on REGO+MEKi in NRAS Q61mut pts: 7.6 wks (range 3-49). Median PFS and OS: 12.9 and 26.4 wks (resp. 15.3 and 26.4 wks in BRAF V600mut pts; 8.6 and 10.1 wks in NRAS Q61mut pts). Conclusions: in heavily pretreated patients with MBM combination of REGO with BRAF-/MEK-inhibitors demonstrated promising anti-tumor activity. Further investigation of safety and clinical activity in a prospective trial is warranted.

Phase III study of adjuvant encorafenib plus binimetinib versus placebo in fully resected stage IIB/C BRAFV600-mutated melanoma: COLUMBUS-AD study design.

TPS9601 Background: Significant progress has been made in the treatment of advanced BRAFV600-mutant melanoma. Encorafenib in combination with binimetinib is a well-tolerated and effective treatment option, providing sustained progression-free and overall survival benefit in unresectable or metastatic setting. The focus has shifted to early-stage disease in order to prevent recurrence. 18% of stage IIB and 25% stage IIC patients die due to melanoma within 10 years from the diagnosis [Gershenwald and al 2017], indicating an unmet medical need. Currently only immunotherapy has been approved in first countries across the world in this setting. There is a need for more treatment options for BRAF-mutated stage II disease. We report here the rationale and design of COLUMBUS-AD (NCT05270044). Methods: COLUMBUS-AD study is an international randomized, placebo-controlled, triple-blind, multicenter Phase III trial evaluating adjuvant encorafenib + binimetinib against placebo in patients with fully resected stage IIB/C BRAF V600-mutant melanoma. Approximately 815 patients will be enrolled. More than 170 sites in up to 26 countries worldwide will participate in the study conducted in collaboration with the European Organisation for Research and Treatment of Cancer (EORTC). Patients will receive encorafenib + binimetinib or placebo for 12 months, or until disease recurrence and will be followed monthly during treatment period, then every 3 months up to year 3, and then at regular intervals. The participants will be followed for a total of 10 years. Patients included in the study must have undergone resection of a stage IIB/C cutaneous melanoma with a BRAFV600E/K mutation, confirmed on resected tumor sample by a central laboratory, and a negative result on sentinel node biopsy. Patients must have recovered from surgery, have an ECOG 0/1, and adequate hematologic, hepatic, cardiac, coagulation and renal functions. Eligible patients will be randomized 1:1 to receive either encorafenib 450 mg once daily plus binimetinib 45 mg twice daily or matching placebos. The primary objective of the study is to evaluate the efficacy of the combination of encorafenib+ binimetinib for prolonging recurrence-free survival (RFS). The secondary objectives are to compare distant metastasis-free survival (DMFS), overall survival (OS), health-related quality of life (QoL), and safety and tolerability between the two arms and to provide additional pharmacokinetic data. Conclusion: COLUMBUS-AD is the first phase 3 randomised trial to evaluate adjuvant BRAFi/MEKi in stage IIB/C melanoma. This study will evaluate whether the combination of encorafenib and binimetinib can decrease the risk for recurrence and improve distant metastasis-free survival and overall survival versus placebo in completely resected IIB/C BRAFV600E/K-mutant cutaneous melanoma. Clinical trial information: NCT05270044 .