BRAF V600突变阳性的晚期黑色素瘤治疗的临床研究进展

多数黑色素瘤具有BRAF V600E/K突变,因此V600成为黑色素瘤精准治疗的重要靶点,并通常可被BRAF抑制剂和MEK抑制剂联合阻断。免疫检查点抑制剂的出现也极大地改善了BRAF V600突变阳性的晚期黑色素瘤患者的治疗结局,探究这部分患者的最佳一线治疗及序贯治疗顺序的临床试验正在开展。本文就精准医疗时代BRAF V600突变阳性的晚期黑色素瘤患者治疗的最新研究进展进行综述。     

BRAF inhibitor activity in V600R metastatic melanoma

Activating mutations in the BRAF gene occur in approximately 50% of melanomas. More than 70% of BRAF mutations are V600E and 10–30% are V600K. Potent and selective BRAF inhibitors have demonstrated significant clinical benefits in patients with V600E and V600K BRAF-mutated melanoma. V600R mutations constitute approximately 3–7% of all BRAF mutations and the activity of BRAF inhibitors in patients with this mutation is unknown. We have treated 45 patients with V600 mutated melanoma including patients with V600R mutation between July 2011 and October 2012 with the selective BRAF inhibitor dabrafenib (n = 43) or vemurafenib (n = 2) via a compassionate access programme. The overall response rate was 50% for the whole population with a progression-free survival of 5.5 months. Five objective responses were seen in six assessable patients with V600R BRAF mutation (n = 9). Our experience suggests that patients with V600R BRAF mutations can be treated successfully with oral BRAF inhibitors, and molecular diagnostic assays should include detection of this type of mutation.     

Vemurafenib in patients with BRAFV600 mutation-positive metastatic melanoma: final overall survival results of the randomized BRIM-3 study

BackgroundThe BRIM-3 trial showed improved progression-free survival (PFS) and overall survival (OS) for vemurafenib compared with dacarbazine in treatment-naive patients with BRAF^V600 mutation–positive metastatic melanoma. We present final OS data from BRIM-3.Patients and methodsPatients were randomly assigned in a 1 : 1 ratio to receive vemurafenib (960 mg twice daily) or dacarbazine (1000 mg/m² every 3 weeks). OS and PFS were co-primary end points. OS was assessed in the intention-to-treat population, with and without censoring of data for dacarbazine patients who crossed over to vemurafenib.ResultsBetween 4 January 2010 and 16 December 2010, a total of 675 patients were randomized to vemurafenib (n = 337) or dacarbazine (n = 338, of whom 84 crossed over to vemurafenib). At the time of database lock (14 August 2015), median OS, censored at crossover, was significantly longer for vemurafenib than for dacarbazine {13.6 months [95% confidence interval (CI) 12.0–15.4] versus 9.7 months [95% CI 7.9–12.8; hazard ratio (HR) 0.81 [95% CI 0.67–0.98];P = 0.03}, as was median OS without censoring at crossover [13.6 months (95% CI 12.0–15.4) versus 10.3 months (95% CI 9.1–12.8); HR 0.81 (95% CI 0.68–0.96);P = 0.01]. Kaplan–Meier estimates of OS rates for vemurafenib versus dacarbazine were 56% versus 46%, 30% versus 24%, 21% versus 19% and 17% versus 16% at 1, 2, 3 and 4 years, respectively. Overall, 173 of the 338 patients (51%) in the dacarbazine arm and 175 of the 337 (52%) of those in the vemurafenib arm received subsequent anticancer therapies, most commonly ipilimumab. Safety data were consistent with the primary analysis.ConclusionsVemurafenib continues to be associated with improved median OS in the BRIM-3 trial after extended follow-up. OS curves converged after ≈3 years, likely as a result of crossover from dacarbazine to vemurafenib and receipt of subsequent anticancer therapies.ClinicalTrials.govNCT01006980.     

Successful treatment of a BRAF V600E-mutant extracranial metastatic anaplastic oligoastrocytoma with vemurafenib and everolimus

Background: Extracranial metastasis is a rare phenomenon of anaplastic oligoastrocytoma. When patients progress after comprehensive treatment, there is often no effective treatment. Rapid development of gene detection technology makes precision treatment of glioma possible.

Patient and methods: A 22-year-old girl was firstly diagnosed with anaplastic oligoastrocytoma WHO grade III-IV in 2014, and progressed rapidly after chemoradiotherapy in multiple extraneural lesions in 2016. She was expected to have a short life and Next-Generation Sequencing (NGS) was applied.

Results: Mutation of BRAF (V600E) was reported by 1st NGS and oral vemurafenib stabilized her disease for 6 months. PIK3CA was reported by 2nd NGS after her progression of vemurafenib. The oral administration of everolimus together with vemurafenib stabilized her disease for another 6 months. However, the patient died due to the rapid progression of the disease on 24 February 2018.

Conclusion: We successfully treated a BRAF V600E-mutated anaplastic oligoastrocytoma with multiple extraneural metastases with vemurafenib and everolimus. For late-staged patients who have no clear and effective treatment plan, NGS may serve as an effective option.     

Open-label,multicentre safety study of vemurafenib in 3219 patients with BRAFV600 mutation-positive metastatic melanoma: 2-year follow-up data and long-term responders' analysis

BackgroundThe orally available BRAF kinase inhibitor vemurafenib is an effective and tolerable treatment option for patients with metastatic melanoma harbouring BRAF^V600 mutations. We assessed the safety of vemurafenib in a large population of patients with few alternative treatment options; we report updated 2-year safety.MethodsThis was an open-label, multicentre study of vemurafenib (960 mg bid) in patients with previously treated or untreated BRAF mutation-positive metastatic melanoma (cobas^® 4800 BRAF V600 Mutation Test). The primary end-point was safety; efficacy end-points were secondary. An exploratory analysis was performed to assess safety outcomes in patients with long duration of response (DOR) (≥12 or ≥24 months).ResultsAfter a median follow-up of 32.2 months (95% CI, 31.1–33.2 months), 3079/3219 patients (96%) had discontinued treatment. Adverse events (AEs) were largely consistent with previous reports; the most common all-grade treatment-related AEs were arthralgia (37%), alopecia (25%) and hyperkeratosis (23%); the most common grade 3/4 treatment-related AEs were squamous cell carcinoma of the skin (8%) and keratoacanthoma (8%). In the exploratory analysis, patients with DOR ≥12 months (n = 287) or ≥24 months (n = 133) were more likely to experience grade 3/4 AEs than the overall population. No new specific safety signals were observed with longer vemurafenib exposure.ConclusionsAfter 2 years' follow-up, safety was maintained in this large group of patients with BRAF^V600 mutation-positive metastatic melanoma who are more representative of routine clinical practice than typical clinical trial populations. These data suggest that long-term vemurafenib treatment is effective and tolerable without the development of new safety signals.     

Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study

BackgroundPrevious analysis of COMBI-d (NCT01584648) demonstrated improved progression-free survival (PFS) and overall survival (OS) with combination dabrafenib and trametinib versus dabrafenib monotherapy in BRAF V600E/K-mutant metastatic melanoma. This study was continued to assess 3-year landmark efficacy and safety after ≥36-month follow-up for all living patients.Patients and methodsThis double-blind, phase 3 study enrolled previously untreated patients with BRAF V600E/K-mutant unresectable stage IIIC or stage IV melanoma. Patients were randomized to receive dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) or dabrafenib plus placebo. The primary endpoint was PFS; secondary endpoints were OS, overall response, duration of response, safety, and pharmacokinetics.ResultsBetween 4 May and 30 November 2012, a total of 423 of 947 screened patients were randomly assigned to receive dabrafenib plus trametinib (n= 211) or dabrafenib monotherapy (n = 212). At data cut-off (15 February 2016), outcomes remained superior with the combination: 3-year PFS was 22% with dabrafenib plus trametinib versus 12% with monotherapy, and 3-year OS was 44% versus 32%, respectively. Twenty-five patients receiving monotherapy crossed over to combination therapy, with continued follow-up under the monotherapy arm (per intent-to-treat principle). Of combination-arm patients alive at 3 years, 58% remained on dabrafenib plus trametinib. Three-year OS with the combination reached 62% in the most favourable subgroup (normal lactate dehydrogenase and <3 organ sites with metastasis) versus only 25% in the unfavourable subgroup (elevated lactate dehydrogenase). The dabrafenib plus trametinib safety profile was consistent with previous clinical trial observations, and no new safety signals were detected with long-term use.ConclusionsThese data demonstrate that durable (≥3 years) survival is achievable with dabrafenib plus trametinib in patients with BRAF V600-mutant metastatic melanoma and support long-term first-line use of the combination in this setting.     

Long-term tolerability of the BRAF inhibitor vemurafenib in patients with metastatic melanoma: current study data and real-life observations

Vemurafenib is a targeted therapy against metastatic melanoma. It specifically inhibits the V600 mutated BRAF kinase in the mitogen-activated protein kinase pathway. Only limited data are available on long-term tolerability and efficacy of this drug. Here, we report and discuss six patients from our own clinical practice who were treated with vemurafenib for 16–27 months. Overall, these long-term responders tolerated vemurafenib well during the prolonged period of therapy. Most of the side-effects occurred during the first 6 months of treatment and were transient. The most common persistent side-effect was phototoxicity, which was manageable by precautionary measures or with dose reduction. Interestingly, even permanent dose reductions of 50?% of the standard dose did not abrogate long lasting remissions but improved tolerability, which is a prerequisite of long-term therapy. In addition to our own clinical experience, this article reviews current study results regarding the tolerability and efficacy of long-term vemurafenib therapy.     

Vemurafenib in patients with BRAFV600 mutation-positive melanoma with symptomatic brain metastases: Final results of an open-label pilot study

Background & AimBrain metastases are frequent in patients with metastatic melanoma, indicating poor prognosis. We investigated the BRAF kinase inhibitor vemurafenib in patients with advanced melanoma with symptomatic brain metastases.MethodsThis open-label trial assessed vemurafenib (960 mg twice a day) in patients with BRAF^V600 mutation-positive metastatic melanoma with non-resectable, previously treated brain metastases. The primary end-point was safety. Secondary end-points included best overall response rate, and progression-free and overall survival.ResultsTwenty-four patients received vemurafenib for a median treatment duration of 3.8 (0.1–11.3) months. The majority of discontinuations were due to disease progression (n = 22). Twenty-three of 24 patients reported at least one adverse event (AE). Grade 3 AEs were reported in four (17%; 95% confidence interval [CI], 4.7–37.4%) patients and included cutaneous squamous cell carcinoma in four patients. Median progression-free survival was 3.9 (95% CI, 3.0–5.5) months, and median survival was 5.3 (95% CI, 3.9–6.6) months. An overall partial response (PR) at both intracranial and extracranial sites was achieved in 10 of 24 (42%; 95% CI, 22.1–63.4) evaluable patients, with stable disease in nine (38%; 95% CI, 18.8–59.4) patients. Of 19 patients with measurable intracranial disease, seven (37%) achieved >30% intracranial tumour regression, and three (16%; 95% CI, 3.4–39.6%) achieved a confirmed PR. Other signs of improvement included reduced need for corticosteroids and enhanced performance status.ConclusionsVemurafenib can be safely used in patients with advanced symptomatic melanoma that has metastasised to the brain and can result in meaningful tumour regression.     

BRAFV600E protein expression and outcome from BRAF inhibitor treatment in BRAFV600E metastatic melanoma

Background:

To examine the association between level and patterns of baseline intra-tumoural BRAF^V600E protein expression and clinical outcome of BRAF^V600E melanoma patients treated with selective BRAF inhibitors.

Methods:

Fifty-eight BRAF^V600E metastatic melanoma patients treated with dabrafenib or vemurafenib on clinical trials had pre-treatment tumour BRAF^V600E protein expression immunohistochemically (IHC) assessed using the BRAF V600E mutant-specific antibody VE1. Sections were examined for staining intensity (score 1–3) and percentage of immunoreactive tumour cells, and from this an immunoreactive score (IRS) was derived (intensity × per cent positive/10). The presence of intra-tumoural heterogeneity for BRAF^V600E protein expression was also assessed. BRAF^V600E expression was correlated with RECIST response, time to best response (TTBR), progression-free survival (PFS) and overall survival (OS).

Results:

Expression was generally high (median IRS 28 (range 5–30)) and homogeneous (78%). Expression of mutated protein BRAF^V600E as measured by intensity, per cent immunoreactive cells, or IRS did not correlate with RECIST response, TTBR, PFS or OS, including on multivariate analysis. Heterogeneity of staining was seen in 22% of cases and did not correlate with outcome.

Conclusion:

In the current study population, IHC-measured pre-treatment BRAF^V600E protein expression does not predict response or outcome to BRAF inhibitor therapy in BRAF^V600E metastatic melanoma patients.     

The safety and efficacy of cobimetinib for the treatment of BRAF V600E or V600K melanoma

Introduction: In the recent years, melanoma patients’ outcome and survival improved, mainly because of systemic treatment improvement with targeted therapy and checkpoint blockade. Targeted therapy with BRAF and MEK inhibitors was approved to treat patients with unresectable or metastatic melanoma, harboring BRAF V600 mutations. This paper addresses the safety and efficacy of cobimetinib, when used in combination with vemurafenib, in the previous mentioned setting.

Areas covered: This article presents an overview on the rationale for clinical development of cobimetinib, as well as the mechanism of action, the efficacy and safety, and the most important trials that led to the approval of the combination therapy with vemurafenib. We searched the PubMed for published papers related to safety and efficacy of cobimetinib, and resistance mechanisms to BRAF inhibition. The abstract databases of the American Society of Clinical Oncology and European Society for Medical Oncology were also searched for updates on the mentioned clinical trials.

Expert commentary: Patients treated with targeted therapy experience a rapid tumor response. However, virtually all patients will develop resistance to treatment. Therapeutic combinations to overcome resistance mechanisms are currently addressed. In the future, targeted therapy strategy will include three or more drugs, probably from different therapeutic classes.     

Health-related quality of life impact in a randomised phase III study of the combination of dabrafenib and trametinib versus dabrafenib monotherapy in patients with BRAF V600 metastatic melanoma

AimTo present the impact of treatments on health-related quality of life (HRQoL) from the double-blind, randomised phase III COMBI-d study that investigated the combination of dabrafenib and trametinib versus dabrafenib monotherapy in patients with BRAF V600E/K-mutant metastatic melanoma. COMBI-d showed significantly prolonged progression-free survival for the combination.MethodsHRQoL was evaluated using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30, a generic cancer questionnaire (completed at baseline, during study treatment, at progression and post progression) assessing various dimensions (global health/QoL, functional status, and symptom impact). A mixed-model, repeated-measures analyses of covariance evaluated differences between arms.ResultsQuestionnaire completion rates were >95% at baseline, >85% to week 40 and >70% at disease progression. Baseline scores across both arms were comparable for all dimensions. Global health dimension scores were significantly better at weeks 8, 16 and 24 for patients receiving the combination during treatment and at progression. The majority of functional dimension scores (physical, social, role, emotional and cognitive functioning) trended in favour of the combination. Pain scores were significantly improved and clinically meaningful (6–13 point difference) for patients receiving the combination for all follow-up assessments versus those receiving dabrafenib monotherapy. For other symptom dimensions (nausea and vomiting, diarrhoea, dyspnoea, and constipation), scores trended in favour of dabrafenib monotherapy.ConclusionThis analysis demonstrates that the combination of dabrafenib and trametinib provides better preservation of HRQoL and pain improvements versus dabrafenib monotherapy while also delaying progression. (Clinicaltrials.gov registration number: NCT01584648).     

An open-label, two-arm, phase I trial of recombinant human interleukin-21 in patients with metastatic melanoma.

PURPOSE: Human interleukin-21 (IL-21) is a pleiotropic class I cytokine that activates CD8(+) T cells and natural killer cells. We report a phase 1 study of recombinant human IL-21 in patients with surgically incurable metastatic melanoma. The primary objective was to investigate safety and tolerability by determining dose-limiting toxicity (DLT). The secondary objectives were to identify a dose response for various biomarkers in the peripheral blood, estimate the minimum biologically effective dose, determine the pharmacokinetics of IL-21, determine if anti-IL-21 antibodies were induced during therapy, and measure effects on tumor size according to Response Evaluation Criteria in Solid Tumors. EXPERIMENTAL DESIGN: Open-label, two-arm, dose escalation trial of IL-21 administered by i.v. bolus injection at dose levels from 1 to 100 microg/kg using two parallel treatment regimens: thrice weekly for 6 weeks (3/wk) or three cycles of daily dosing for 5 days followed by 9 days of rest (5+9). RESULTS: Twenty-nine patients entered the study. IL-21 was generally well tolerated and no DLTs were observed at the 1, 3, and 10 microg/kg dose levels. In the 3/wk regimen, DLTs were increased in alanine aminotransferase, neutropenia, and lightheadedness with fever and rigors. DLTs in the 5+9 regimen were increased in aspartate aminotransferase and alanine aminotransferase, neutropenia, fatigue, and thrombocytopenia. The maximum tolerated dose was declared to be 30 microg/kg for both regimens. Effects on biomarkers were observed at all dose levels, including increased levels of soluble CD25 and up-regulation of perforin and granzyme B mRNA in CD8(+) cells. One partial tumor response observed after treatment with IL-21 for 2 x 6 weeks (3/wk) became complete 3 months later. CONCLUSIONS: IL-21 is biologically active at all dose levels administered and is generally well tolerated, and phase 2 studies have commenced using 30 microg/kg in the 5+9 regimen.     

A randomized phase I/II study of continuous versus intermittent intravenous interferon gamma in patients with metastatic melanoma

Thirty patients with documented metastatic melanoma were randomly assigned to receive recombinant DNA-produced gamma-interferon (specific activity approximately, 20 MU/mg) intravenously (IV) over either two or 24 hours at dosages of 3, 30, 300, 1,000, or 3,000 micrograms/m2. Objective toxicity resembled that of alpha-interferon and included fever, chills, myalgias, headache, and fatigue. Neutropenia, elevations in liver enzymes, tachyarrhythmias, and CNS changes also were noted. Dose-limiting toxicity included neutropenia, liver enzyme abnormality, constitutional symptoms, and a change in mental status. The incidence of toxicity was qualitatively similar in both two- and 24-hour treatment arms, but was quantitatively more severe in the 24-hour continuous infusion arm. Maximum tolerated dose was 1,000 micrograms/m2 in both schedules. Pharmacokinetic studies showed a half-life of six to nine hours. One patient had a complete response after two cycles of therapy and an additional patient entered partial remission after three cycles. Recombinant gamma-interferon (rIRN-gamma) is tolerated at dosages of 1,000 micrograms/m2 administered daily either by two or 24 hour infusion for 14 days in patients with metastatic melanoma. The responses documented in this early trial warrant further evaluation for the treatment of metastatic melanoma.