Network indirect comparison of 3 BRAF + MEK inhibitors for the treatment of advanced BRAF mutated melanoma

Economic Evaluation of Three BRAF + MEK Inhibitors for the Treatment of Advanced Unresectable Melanoma With BRAF Mutation From a US Payer Perspective

BACKGROUND

The combinations of BRAF + MEK inhibitors-encorafenib (ENC) + binimetinib (BIN), cobimetinib (COB) + vemurafenib (VEM), and dabrafenib (DAB) + trametinib (TRA)-are recommended for the treatment of BRAF-mutated advanced melanoma.

OBJECTIVE

To assess the cost-effectiveness and cost-utility of ENC + BIN versus COB + VEM versus DAB + TRA from a US payer perspective.

METHODS

A Markov model was constructed to simulate a hypothetical cohort over a time horizon of 10 years. The overall survival (OS) and progression-free survival (PFS) curves were independently digitized from a randomized controlled trial for ENC + BIN and fitted using R software. Published and indirectly estimated hazard ratios were used to fit OS and PFS curves for COB + VEM and DAB + TRA. Costs, life-year gains, and quality-adjusted life years (QALYs) associated with the 3 treatment combinations were estimated. A base case analysis and probabilistic sensitivity analysis (PSA) were conducted to estimate the incremental cost-utility ratio (ICUR). A discount rate of 3.5% was applied on cost and outcomes.

RESULTS

The ENC + BIN versus COB + VEM comparison was associated with an ICUR of $656 233 per QALY gained. The ENC + BIN versus DAB + TRA comparison was associated with an ICUR of $3 135 269 per QALY gained. The DAB + TRA combination dominated COB + VEM. The base case analysis estimates were confirmed by the PSA estimates. ENC + BIN was the most cost-effective combination at a high willingness-to-pay (WTP) threshold of $573 000 per QALY and $1.5 million/QALY when compared to COB + VEM and DAB + TRA, respectively.

CONCLUSION AND RELEVANCE

Given current prices and acceptable WTP thresholds, our study suggests that DAB + TRA is the optimum treatment. In this study, ENC + BIN was cost-effective only at a very high WTP per QALY threshold.

Head-to-Head Comparison of BRAF/MEK Inhibitor Combinations Proposes Superiority of Encorafenib Plus Trametinib in Melanoma

Simple Summary

A decade ago, the diagnosis of metastatic melanoma was mostly a death sentence. This has changed since new therapies became widely available in the clinical setting. In addition to checkpoint inhibitors, targeted therapy with BRAF and MEK inhibitors is standard care for BRAF-mutated melanoma, which accounts for almost half of all melanoma cases. The second largest group of melanoma patients, whose tumors harbor a mutation in the NRAS gene, demonstrates only a limited response to targeted therapy with MEK inhibitors. The aim of this investigation was to directly compare all possible BRAF/MEK inhibitor combinations in addition to the currently applied regimens. The analyzed data suggested that the combination of the BRAF inhibitor encorafenib and the MEK inhibitor trametinib demonstrated the highest anti-tumor activity in both, BRAF- and NRAS-mutated melanoma. This combination is not presently used in patient treatment, and therefore, deserves an opportunity to become part of clinical trials.

Abstract

BRAFV600 mutations in melanoma are targeted with mutation-specific BRAF inhibitors in combination with MEK inhibitors, which have significantly increased overall survival, but eventually lead to resistance in most cases. Additionally, targeted therapy for patients with NRASmutant melanoma is difficult. Our own studies showed that BRAF inhibitors amplify the effects of MEK inhibitors in NRASmutant melanoma. This study aimed at identifying a BRAF and MEK inhibitor combination with superior anti-tumor activity to the three currently approved combinations. We, thus, assessed anti-proliferative and pro-apoptotic activities of all nine as well as resistance-delaying capabilities of the three approved inhibitor combinations in a head-to-head comparison in vitro. The unconventional combination encorafenib/trametinib displayed the highest activity to suppress proliferation and induce apoptosis, acting in an additive manner in BRAFmutant and in a synergistic manner in NRASmutant melanoma cells. Correlating with current clinical studies of approved inhibitor combinations, encorafenib/binimetinib prolonged the time to resistance most efficiently in BRAFmutant cells. Conversely, NRASmutant cells needed the longest time to establish resistance when treated with dabrafenib/trametinib. Together, our data indicate that the most effective combination might not be currently used in clinical settings and could lead to improved overall responses.

Acceptability of Drugs in the Treatment of Unresectable/Metastatic BRAF V600-Mutant Melanoma: A Systematic Review and Network Meta-Analysis

Background

Although many novel regimens have entered the treatment paradigm for unresectable/metastatic BRAF V600-mutant melanoma, there is still a lack of head-to-head comparison in terms of security. We conducted a network meta-analysis to compare the risk of adverse events (AEs) across different treatments and to provide an acceptability ranking for patients.

Methods

A systematic literature review was conducted in Embase, PubMed, WHO International Clinical Trials Registry Platform, and Clinical Trials.gov with a time frame from database inception to December 24, 2021. We retrieved evidence on the cumulative incidence of any-grade AEs means grades 1-5 AEs (regardless of severity) and severe AEs based on the pooled risk ratios (RRs) and 95% credible intervals (95% CrI).

Results

Twelve publications and thirteen treatments enrolling 5,803 patients were included. For any-grade AEs, the acceptability of combined dabrafenib and trametinib is superior to the combination of vemurafenib and cobimetinib (RR: 0.94; Crl: 0.89, 0.98). Furthermore, nivolumab combined with ipilimumab increases any-grade AEs than single-agent ipilimumab (RR: 0.90; Crl: 0.83, 0.96) or nivolumab (RR: 0.90; Crl: 0.84, 0.97). For severe AEs, dabrafenib has the best acceptability than single-agent vemurafenib (RR: 0.66; Crl: 0.50, 0.87) or encorafenib (RR: 0.64; Crl: 0.43, 0.94). In addition, ipilimumab (SUCRA: 0.87) ranks first in the acceptability for any-grade AEs, and nivolumab (SUCRA: 0.95) ranks first in the acceptability for severe AEs. The ranking of the combination of vemurafenib and cobimetinib (SUCRA: 0.66) is superior to encorafenib in combination with binimetinib (SUCRA: 0.39) and combination of vemurafenib and cobimetinib (SUCRA: 0.18).

Conclusions

We identified the lowest AE risk treatment options for BRAF V600-mutant melanoma patients. In general, immunotherapy (ipilimumab or nivolumab) has better acceptability than most targeted therapies, and triplet therapies are related with the worst acceptability. Moreover, single-agent dabrafenib can be used as the first choice in monotherapy, and the combination of dabrafenib and trametinib is the preferred combination therapy. Overall, the combination of immunotherapy drugs increases any-grade and severe AEs than a single agent, whereas the condition of targeted therapy drugs cannot be simply generalized. Therefore, this information can facilitate evidence-based decision-making and support optimizing treatment and outcomes in clinical practice.

Cautious addition of targeted therapy to PD-1 inhibitors after initial progression of BRAF mutant metastatic melanoma on checkpoint inhibitor therapy

Background

Virtually all metastatic patients with metastatic melanoma who progress after initial treatment with PD-1 or CTLA-4 directed antibodies will die of their disease. Salvage options are urgently needed. It is theoretically attractive to combine immunotherapy with targeted agents in progressing patients with BRAF mutation positive melanoma, but the toxicity of combined treatment has proven challenging.

Methods

We performed a retrospective analysis of our patient database and identified 23 patients who progressed on initial checkpoint inhibitor treatment, who subsequently had cautious addition of BRAF±MEK inhibitor therapy to continued PD-1 antibody treatment.

Results

We found an objective response rate of 55% in second line therapy, with a median progression-free survival of 33.4 months and median overall survival of 34.1 months, with 40% of patients in unmaintained remission at over 3 years. Ten of 12 responding patients were able to discontinue all therapy and continue in unmaintained remission. Toxicity of this approach was generally manageable (21.7% grade 3–5 toxicity). There was 1 early sudden death for unknown reasons in a responding patient.

Discussion

Our results suggest that 2nd line therapy with PD-1 inhibitors plus BRAF±MEK inhibitors has substantial activity and manageable toxicity. This treatment can induce additional durable complete responses in patients who have progressed on initial immunotherapy. These results suggest further evaluation be performed of sequential PD-1 antibody treatment with cautious addition of targeted therapy in appropriate patients.

Comparative efficacy of dabrafenib + trametinib versus treatment options for metastatic melanoma in first-line settings

Aim: The objective was to systematically review the literature and assess the relative efficacy of agents approved in first-line settings via network meta-analysis. Materials & methods: A literature review was conducted via searching different medical databases. The eligibility criteria included Phase II or III randomized controlled trials that had enrolled treatment-naive adult patients with advanced/metastatic melanoma. Results: The network meta-analysis results suggested that dabrafenib + trametinib significantly prolongs the survival outcomes compared with the monotherapies and had comparable efficacy profile compared with encorafenib + binimetinib and cobimetinib + vemurafenib. In comparison with immunotherapies, the results varied for progression-free survival and overall survival. Conclusion: Long-term survival data of dabrafenib + trametinib establishes the combination as one of the preferred treatment options for previously untreated melanoma patients.

Clinical Implications of Acquired BRAF Inhibitors Resistance in Melanoma

Understanding the role of mitogen-activated protein kinase (MAPK) pathway-activating mutations in the development and progression of melanoma and their possible use as therapeutic targets has substantially changed the management of this neoplasm, which, until a few years ago, was burdened by severe mortality. However, the presence of numerous intrinsic and extrinsic mechanisms of resistance to BRAF inhibitors compromises the treatment responses’ effectiveness and durability. The strategy of overcoming these resistances by combination therapy has proved successful, with the additional benefit of reducing side effects derived from paradoxical activation of the MAPK pathway. Furthermore, the use of other highly specific inhibitors, intermittent dosing schedules and the association of combination therapy with immune checkpoint inhibitors are promising new therapeutic strategies. However, numerous issues related to dose, tolerability and administration sequence still need to be clarified, as is to be expected from currently ongoing trials. In this review, we describe the clinical results of using BRAF inhibitors in advanced melanoma, with a keen interest in strategies aimed at overcoming resistance.

Targeted and immunotherapies in BRAF mutant melanoma: where we stand and what to expect

The therapeutic landscape for melanoma has evolved drastically in the past decade. Currently, immune checkpoint inhibitors and small-molecule inhibitors targeting the mitogen-activated protein kinase (MAPK) pathway are the two mainstay therapies for BRAF^V600 mutant advanced melanoma. Although MAPK dependence has been variably demonstrated in melanomas lacking BRAF^V600 mutations, definitive evidence of benefit with MAPK inhibitors has not been demonstrated. Thus, in the BRAF^V600 'wild-type' setting, immune checkpoint inhibitors are the standalone option(s). In the BRAF^V600 mutant setting, there is no definitive evidence prioritizing one therapeutic modality over another. Herein, we review the updated data of the pivotal phase III randomized controlled trials that established the standard-of-care first-line treatment for advanced melanoma, as it provides insights into long-term benefit, which is a major factor in therapy selection. We discuss the clinical considerations for choosing between these therapies in the front-line setting and beyond, specifically for patients with BRAF^V600 mutant melanoma based on currently available evidence. We have previously proposed a time-dependent resistance paradigm in which future therapeutic development strategies can be rooted. We also discuss how these Food and Drug Administration (FDA)-approved therapeutic modalities are being pursued earlier in the course of disease management, namely in adjuvant and neoadjuvant settings. FDA-approved interlesional oncolytic virotherapy in the modern era is also briefly discussed.