Three-Year Overall Survival with Tebentafusp in Metastatic Uveal Melanoma.

BACKGROUND: Tebentafusp, a T-cell receptor-bispecific molecule that targets glycoprotein 100 and CD3, is approved for adult patients who are positive for HLA-A*02:01 and have unresectable or metastatic uveal melanoma. The primary analysis in the present phase 3 trial supported a long-term survival benefit associated with the drug. METHODS: We report the 3-year efficacy and safety results from our open-label, phase 3 trial in which HLA-A*02:01-positive patients with previously untreated metastatic uveal melanoma were randomly assigned in a 2:1 ratio to receive tebentafusp (tebentafusp group) or the investigator's choice of therapy with pembrolizumab, ipilimumab, or dacarbazine (control group), with randomization stratified according to the lactate dehydrogenase level. The primary end point was overall survival. RESULTS: At a minimum follow-up of 36 months, median overall survival was 21.6 months in the tebentafusp group and 16.9 months in the control group (hazard ratio for death, 0.68; 95% confidence interval, 0.54 to 0.87). The estimated percentage of patients surviving at 3 years was 27% in the tebentafusp group and 18% in the control group. The most common treatment-related adverse events of any grade in the tebentafusp group were rash (83%), pyrexia (76%), pruritus (70%), and hypotension (38%). Most tebentafusp-related adverse events occurred early during treatment, and no new adverse events were observed with long-term administration. The percentage of patients who discontinued treatment because of adverse events continued to be low in both treatment groups (2% in the tebentafusp group and 5% in the control group). No treatment-related deaths occurred. CONCLUSIONS: This 3-year analysis supported a continued long-term benefit of tebentafusp for overall survival among adult HLA-A*02:01-positive patients with previously untreated metastatic uveal melanoma. (Funded by Immunocore; IMCgp100-202 ClinicalTrials.gov number, NCT03070392; EudraCT number, 2015-003153-18.).

Individualised neoantigen therapy mRNA-4157 (V940) plus pembrolizumab versus pembrolizumab monotherapy in resected melanoma (KEYNOTE-942): a randomised, phase 2b study.

BACKGROUND: Checkpoint inhibitors are standard adjuvant treatment for stage IIB-IV resected melanoma, but many patients recur. Our study aimed to evaluate whether mRNA-4157 (V940), a novel mRNA-based individualised neoantigen therapy, combined with pembrolizumab, improved recurrence-free survival and distant metastasis-free survival versus pembrolizumab monotherapy in resected high-risk melanoma. METHODS: We did an open-label, randomised, phase 2b, adjuvant study of mRNA-4157 plus pembrolizumab versus pembrolizumab monotherapy in patients, enrolled from sites in the USA and Australia, with completely resected high-risk cutaneous melanoma. Patients with completely resected melanoma (stage IIIB-IV) were assigned 2:1 to receive open-label mRNA-4157 plus pembrolizumab or pembrolizumab monotherapy. mRNA-4157 was administered intramuscularly (maximum nine doses) and pembrolizumab intravenously (maximum 18 doses) in 3-week cycles. The primary endpoint was recurrence-free survival in the intention-to-treat population. This ongoing trial is registered at ClinicalTrials.gov, NCT03897881. FINDINGS: From July 18, 2019, to Sept 30, 2021, 157 patients were assigned to mRNA-4157 plus pembrolizumab combination therapy (n=107) or pembrolizumab monotherapy (n=50); median follow-up was 23 months and 24 months, respectively. Recurrence-free survival was longer with combination versus monotherapy (hazard ratio [HR] for recurrence or death, 0·561 [95% CI 0·309-1·017]; two-sided p=0·053), with lower recurrence or death event rate (24 [22%] of 107 vs 20 [40%] of 50); 18-month recurrence-free survival was 79% (95% CI 69·0-85·6) versus 62% (46·9-74·3). Most treatment-related adverse events were grade 1-2. Grade ≥3 treatment-related adverse events occurred in 25% of patients in the combination group and 18% of patients in the monotherapy group, with no mRNA-4157-related grade 4-5 events. Immune-mediated adverse event frequency was similar for the combination (37 [36%]) and monotherapy (18 [36%]) groups. INTERPRETATION: Adjuvant mRNA-4157 plus pembrolizumab prolonged recurrence-free survival versus pembrolizumab monotherapy in patients with resected high-risk melanoma and showed a manageable safety profile. These results provide evidence that an mRNA-based individualised neoantigen therapy might be beneficial in the adjuvant setting. FUNDING: Moderna in collaboration with Merck Sharp & Dohme, a subsidiary of Merck & Co, Rahway, NJ, USA.

Bromodomain inhibition overcomes treatment resistance in distinct molecular subtypes of melanoma.

Therapy of BRAF-mutant melanoma with selective inhibitors of BRAF (BRAFi) and MEK (MEKi) represents a major clinical advance but acquired resistance to therapy has emerged as a key obstacle. To date, no clinical approaches successfully resensitize to BRAF/MEK inhibition. Here, we develop a therapeutic strategy for melanoma using bromosporine, a bromodomain inhibitor. Bromosporine (bromo) monotherapy produced significant anti-tumor effects against established melanoma cell lines and patient-derived xenografts (PDXs). Combinatorial therapy involving bromosporine and cobimetinib (bromo/cobi) showed synergistic anti-tumor effects in multiple BRAFi-resistant PDX models. The bromo/cobi combination was superior in vivo to standard BRAFi/MEKi therapy in the treatment-naive BRAF-mutant setting and to MEKi alone in the setting of immunotherapy-resistant NRAS- and NF1-mutant melanoma. RNA sequencing of xenografts treated with bromo/cobi revealed profound down-regulation of genes critical to cell division and mitotic progression. Bromo/cobi treatment resulted in marked DNA damage and cell-cycle arrest, resulting in induction of apoptosis. These studies introduce bromodomain inhibition, alone or combined with agents targeting the mitogen activated protein kinase pathway, as a rational therapeutic approach for melanoma refractory to standard targeted or immunotherapeutic approaches.

The clinical significance of adenomatous polyposis coli (APC) and catenin Beta 1 (CTNNB1) genetic aberrations in patients with melanoma.

BACKGROUND: Melanoma-intrinsic activated ß-catenin pathway, the product of the catenin beta 1 (CTNNB1) gene, has been associated with low/absent tumor-infiltrating lymphocytes, accelerated tumor growth, metastases development, and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. Little is known about the association between the adenomatous polyposis coli (APC) and CTNNB1 gene mutations in stage IV melanoma with immunotherapy response and overall survival (OS). METHODS: We examined the prognostic significance of somatic APC/CTNNB1 mutations in the Cancer Genome Atlas Project for Skin Cutaneous Melanoma (TCGA-SKCM) database. We assessed APC/CTNNB1 mutations as predictors of response to immunotherapies in a clinicopathologically annotated metastatic patient cohort from three US melanoma centers. RESULTS: In the TCGA-SKCM patient cohort (n = 434) presence of a somatic APC/CTNNB1 mutation was associated with a worse outcome only in stage IV melanoma (n = 82, median OS of APC/CTNNB1 mutants vs. wild-type was 8.15 vs. 22.8 months; log-rank hazard ratio 4.20, p = 0.011). APC/CTNNB1 mutation did not significantly affect lymphocyte distribution and density. In the 3-melanoma institution cohort, tumor tissues underwent targeted panel sequencing using two standards of care assays. We identified 55 patients with stage IV melanoma and APC/CTNNB1 genetic aberrations (mut) and 169 patients without (wt). At a median follow-up of more than 25 months for both groups, mut compared with wt patients had slightly more frequent (44% vs. 39%) and earlier (66% vs. 45% within six months from original diagnosis of stage IV melanoma) development of brain metastases. Nevertheless, time-to-development of brain metastases was not significantly different between the two groups. Fortunately, mut patients had similar clinical benefits from PD-1 inhibitor-based treatments compared to wt patients (median OS 26.1 months vs. 29.9 months, respectively, log-rank p = 0.23). Less frequent mutations in the NF1, RAC1, and PTEN genes were seen in the mut compared with wt patients from the 3-melanoma institution cohort. Analysis of brain melanoma tumor tissues from a separate craniotomy patient cohort (n = 55) showed that melanoma-specific, activated ß-catenin (i.e., nuclear localization) was infrequent (n = 3, 6%) and not prognostic in established brain metastases. CONCLUSIONS: APC/CTNNB1 mutations are associated with a worse outcome in stage IV melanoma and early brain metastases independent of tumor-infiltrating lymphocyte density. However, PD1 inhibitor-based treatments provide comparable benefits to both mut and wt patients with stage IV melanoma.

Reappraisal of the prognostic significance of mitotic rate supports its reincorporation into the melanoma staging system.

BACKGROUND: Mitotic rate is a strong, independent prognostic factor in patients with melanoma. However, incorporating it into the melanoma staging system has proved challenging. METHODS: The prognostic impact of mitotic rate was assessed in a melanoma cohort comprising 5050 patients from 2 geographically distinct populations. Computer-generated cut points for mitotic rate were constructed to determine its impact on melanoma-associated survival using Kaplan-Meier and multivariate regression analyses. The impact of mitotic rate also was assessed in randomly split training and validation sets. RESULTS: Mitotic rate had a nonlinear impact on survival, as evidenced by unequally spaced cut points. An index incorporating these cut points that was constructed from one population produced significantly more accurate predictions of survival in the other population than using the entire scale of mitotic rate. An index constructed from the combined cohort was found to be independently predictive of survival, with an impact comparable to that of ulceration. Optimal high-versus-low cut points for mitotic rate were generated separately for each T category (<2 mitoses/mm2 vs ≥2 mitoses/mm2 for T1 melanoma, <4 mitoses/mm2 vs ≥4 mitoses/mm2 for T2 melanoma, <6 mitoses/mm2 vs ≥6/mitoses/mm2 for T3 melanoma, and <7 mitoses/mm2 vs ≥7 mitoses/mm2 for T4 melanoma). Using Kaplan-Meier analysis, elevated mitotic rate was found to have an impact on survival comparable to that of ulceration within each T category. Application of the index for mitotic rate that was constructed from the training data set demonstrated an independent impact in the validation data set, with a significance similar to that of ulceration. CONCLUSIONS: The results of the current study demonstrated the comparable prognostic impact of mitotic rate and ulceration, providing support for its reincorporation into the T category.

Drug responses are conserved across patient-derived xenograft models of melanoma leading to identification of novel drug combination therapies.

BACKGROUND: Patient-derived xenograft (PDX) mouse tumour models can predict response to therapy in patients. Predictions made from PDX cultures (PDXC) would allow for more rapid and comprehensive evaluation of potential treatment options for patients, including drug combinations. METHODS: We developed a PDX library of BRAF-mutant metastatic melanoma, and a high-throughput drug-screening (HTDS) platform utilising clinically relevant drug exposures. We then evaluated 34 antitumor agents across eight melanoma PDXCs, compared drug response to BRAF and MEK inhibitors alone or in combination with PDXC and the corresponding PDX, and investigated novel drug combinations targeting BRAF inhibitor-resistant melanoma. RESULTS: The concordance of cancer-driving mutations across patient, matched PDX and subsequent PDX generations increases as variant allele frequency (VAF) increases. There was a high correlation in the magnitude of response to BRAF and MEK inhibitors between PDXCs and corresponding PDXs. PDXCs and corresponding PDXs from metastatic melanoma patients that progressed on standard-of-care therapy demonstrated similar resistance patterns to BRAF and MEK inhibitor therapy. Importantly, HTDS identified novel drug combinations to target BRAF-resistant melanoma. CONCLUSIONS: The biological consistency observed between PDXCs and PDXs suggests that PDXCs may allow for a rapid and comprehensive identification of treatments for aggressive cancers, including combination therapies.

Phase 1 study of the combination of vemurafenib, carboplatin, and paclitaxel in patients with BRAF-mutated melanoma and other advanced malignancies.

BACKGROUND: BRAF inhibitors are effective against selected BRAFV600 -mutated tumors. Preclinical data suggest that BRAF inhibition in conjunction with chemotherapy has increased therapeutic activity. METHODS: Patients with advanced cancers and BRAF mutations were enrolled into a dose-escalation study (3+3 design) to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs). RESULTS: Nineteen patients with advanced cancers and BRAF mutations were enrolled and received vemurafenib (480-720 mg orally twice a day), carboplatin (area under the curve [AUC] 5-6 intravenously every 3 weeks), and paclitaxel (100-135 mg/m2 intravenously every 3 weeks). The MTD was not reached, and vemurafenib at 720 mg twice a day, carboplatin at AUC 5, and paclitaxel at 135 mg/m2 were the last safe dose levels. DLTs included a persistent grade 2 creatinine elevation (n = 1), grade 3 transaminitis (n = 1), and grade 4 thrombocytopenia (n = 1). Non-dose-limiting toxicities that were grade 3 or higher and occurred in more than 2 patients included grade 3/4 neutropenia (n = 5), grade 3/4 thrombocytopenia (n = 5), grade 3 fatigue (n = 4), and grade 3 anemia (n = 3). Of the 19 patients, 5 (26%; all with melanoma) had a partial response (PR; n = 4) or complete response (CR; n = 1); these responses were mostly durable and lasted 3.1 to 54.1 months. Of the 13 patients previously treated with BRAF and/or mitogen-activated protein kinase kinase (MEK) inhibitors, 4 (31%) had a CR (n = 1) or PR (n = 3). Patients not treated with prior platinum therapy had a higher response rate than those who did (45% vs 0%; P = .045). CONCLUSIONS: The combination of vemurafenib, carboplatin, and paclitaxel is well tolerated and demonstrates encouraging activity, predominantly in patients with advanced melanoma and BRAFV600 mutations, regardless of prior treatment with BRAF and/or MEK inhibitors.

Correction to: Intraoperative Imaging with a Portable Gamma Camera May Reduce the False-Negative Rate for Melanoma Sentinel Lymph Node Surgery.

The article "Intraoperative Imaging with a Portable Gamma Camera May Reduce the False-Negative Rate for Melanoma Sentinel Lymph Node Surgery," written by Stanley P. Leong et al., was originally published electronically on the publisher's internet portal (currently SpringerLink) on August 13, 2018, without open access.

Intraoperative Imaging with a Portable Gamma Camera May Reduce the False-Negative Rate for Melanoma Sentinel Lymph Node Surgery.

BACKGROUND: Preoperative imaging and intraoperative gamma probe (GP) localization is standard for identifying sentinel lymph nodes (SLNs) in melanoma patients. The aim of this prospective Institutional Review Board-approved study was to investigate whether an intraoperative portable gamma camera (PGC) improves SLN detection over the GP. METHODS: Lymphoscintigraphy and single photon emission computed tomography/computed tomography were performed after injection of 99mTc-Tilmanocept in melanoma patients (≥ 18 years, Breslow thickness ≥ 1.0 mm). A GP was used to localize the SLNs in each basin, which was explored by the GP to ensure that the operative field was < 10% counts of the hottest SLN. The PGC was then used after a negative GP screening. Any residual hotspots identified by the PGC were considered as additional SLNs and were removed following the 10% rule. RESULTS: Preoperative imaging of 100 patients identified 138 SLN basins, with 306 SLNs being identified by conventional surgery. The PGC localized 89 additional SLNs in 54 patients. Thus, the PGC identified an additional 23% of SLNs [95% confidence interval (CI) 18-27%]. Four of these 89 SLNs showed micrometastasis in four patients, in two of whom the only tumor-positive SLN was identified by the PGC, preventing two false-negative cases. Thus, the null hypothesis that the PGC did not detect additional positive SLNs was rejected (p = 0.000). The overall SLN positive rate was 9.9% (39/395, 95% CI 6-12), and the overall patient positive rate was increased using the PGC, from 25 to 27% (27/100). CONCLUSIONS: Intraoperative PGC imaging yielded additional SLNs in a significant number of patients over GP alone. Identification of these additional SLNs resulted in upstaging of four patients with two patients being converted from a negative to a positive status, thus, preventing two false-negative cases.

Survival and clinical outcomes of patients with melanoma brain metastasis in the era of checkpoint inhibitors and targeted therapies.

BACKGROUND: Melanoma brain metastasis is associated with an extremely poor prognosis, with a median overall survival of 4-5 months. Since 2011, the overall survival of patients with stage IV melanoma has been significantly improved with the advent of new targeted therapies and checkpoint inhibitors. We analyze the survival outcomes of patients diagnosed with brain metastasis after the introduction of these novel drugs. METHODS: We performed a retrospective analysis of our melanoma center database and identified 79 patients with brain metastasis between 2011 and 2015. RESULTS: The median time from primary melanoma diagnosis to brain metastasis was 3.2 years. The median overall survival duration from the time of initial brain metastasis was 12.8 months. Following a diagnosis of brain metastasis, 39 (49.4%), 28 (35.4%), and 24 (30.4%) patients were treated with anti-CTLA-4 antibody, anti-PD-1 antibody, or BRAF inhibitors (with or without a MEK inhibitor), with a median overall survival of 19.2 months, 37.9 months and 12.7 months, respectively. Factors associated with significantly reduced overall survival included male sex, cerebellar metastasis, higher number of brain lesions, and treatment with whole-brain radiation therapy. Factors associated with significantly longer overall survival included treatment with craniotomy, stereotactic radiosurgery, or with anti-PD-1 antibody after initial diagnosis of brain metastasis. CONCLUSIONS: These results show a significant improvement in the overall survival of patients with melanoma brain metastasis in the era of novel therapies. In addition, they suggest the activity of anti-PD-1 therapy specifically in the setting of brain metastasis.

Clinicopathological features and clinical outcomes associated with TP53 and BRAFNon-V600 mutations in cutaneous melanoma patients.

BACKGROUND: BRAFV600 , NRAS, TP53, and BRAFNon-V600 are among the most common mutations detected in non-acral cutaneous melanoma patients. Although several studies have identified clinical and pathological features associated with BRAFV600 and NRAS mutations, limited data are available regarding the correlates and significance of TP53 and BRAFNon-V600 mutations. METHODS: This study analyzed the patient demographics, primary tumor features, and clinical outcomes of a large cohort of non-acral cutaneous melanoma patients who had undergone clinically indicated molecular testing (n = 926). RESULTS: The prevalence of BRAFV600 , NRAS, TP53, and BRAFNon-V600 mutations was 43%, 21%, 19%, and 7%, respectively. The presence of a TP53 mutation was associated with older age (P = .019), a head and neck primary tumor site (P = .0001), and longer overall survival (OS) from the diagnosis of stage IV disease in univariate (P = .039) and multivariate analyses (P = .015). BRAFNon-V600 mutations were associated with older age (P = .005) but not with primary tumor features or OS from stage IV. Neither TP53 nor BRAFNon-V600 mutations correlated significantly with OS with frontline ipilimumab treatment, and the TP53 status was not significantly associated with outcomes with frontline BRAF inhibitor therapy. Eleven patients with BRAFNon-V600 mutations were treated with a BRAF inhibitor. Three patients were not evaluable for a response because of treatment cessation for toxicities; the remaining patients had disease progression as the best response to therapy. CONCLUSIONS: These results add to the understanding of the clinical features associated with TP53 and BRAFNon-V600 mutations in advanced cutaneous melanoma patients, and they support the rationale for evaluating the prognostic significance of TP53 in other cohorts of melanoma patients. Cancer 2017;123:1372-1381. © 2016 American Cancer Society.

A phase II study of ipilimumab plus temozolomide in patients with metastatic melanoma.

Checkpoint blockade has revolutionized the treatment of melanoma; however, it benefits only the minority of patients. Several agents have been combined with immunotherapy to improve T-cell activation and persistence including growth factor, chemotherapy, and radiation. Preclinical data suggest that temozolomide, which metabolizes to the same active compound as dacarbazine, selectively depletes regulatory T cells. This potential immunomodulatory effect of temozolomide provides rationale for combination with ipilimumab. We performed an open-label single-arm phase II study of ipilimumab plus temozolomide in the frontline setting for patients with metastatic melanoma and LDH ≤2× upper limit of normal. Ipilimumab was given at 10 mg/kg on day 1 and temozolomide 200 mg/m2 orally days 1-4 every 3 weeks for four doses followed by maintenance ipilimumab every 12 weeks plus temozolomide every 4 weeks. The primary objective of the study was 6-month PFS. A total of 64 patients were enrolled and the 6-month PFS was 45% with median OS of 24.5 months. There were 10 (15.6%) confirmed partial responses and 10 (15.6%) confirmed complete responses. Duration of response amongst responders is 35 months with 10 patients demonstrating an ongoing response at median follow-up of 20 months. There were no deaths or unexpected toxicities on study. The most common gastrointestinal side effects were nausea and constipation rather than diarrhea or colitis. These results suggest that the combination of induction ipilimumab plus temozolomide could potentially be an effective strategy to enhance antitumor activity with a manageable toxicity profile. These findings warrant further evaluation in a large prospective study.

A phase I dose-escalation study of Selumetinib in combination with Erlotinib or Temsirolimus in patients with advanced solid tumors.

Background Combinations of molecularly targeted agents may provide optimal anti-tumor activity and improve clinical outcomes for patients with advanced cancers. Selumetinib (AZD6244, ARRY-142886) is an oral, potent and highly selective, allosteric inhibitor of MEK1/2, a component of the RAS/RAF/MEK/ERK pathway which is constitutively activated in many cancers. We investigated the safety, tolerability, and pharmacokinetics (PK) of selumetinib in combination with molecularly targeted drugs erlotinib or temsirolimus in patients with advanced solid tumors. Methods Two-part study: dose escalation, to determine the maximum tolerated dose (MTD) of selumetinib in combination with erlotinib 100 mg once daily (QD) or temsirolimus 25 mg once weekly, followed by dose expansion at the respective combination MTDs to further investigate safety and anti-tumor effects. Results 48 patients received selumetinib plus erlotinib and 32 patients received selumetinib plus temsirolimus. The MTD with erlotinib 100 mg QD was selumetinib 100 mg QD, with diarrhea being dose limiting. The most common all grade adverse events (AEs): diarrhea, rash, nausea, and fatigue. Four (8.3%) patients had ≥12 weeks stable disease. The MTD with temsirolimus 25 mg once weekly was selumetinib 50 mg twice daily (BID), with mucositis and neutropenia being dose limiting. The most commonly reported AEs: nausea, fatigue, diarrhea, and mucositis. Ten (31.3%) patients had ≥12 weeks stable disease. The combination PK profiles were comparable to previously observed monotherapy profiles. Conclusions MTDs were established for selumetinib in combination with erlotinib or temsirolimus. Overlapping toxicities prevented the escalation of selumetinib to its recommended phase II monotherapy dose of 75 mg BID. TRIAL REGISTRATION: ClinicalTrials.gov NCT00600496; registered 8 July 2009.

A phase I dose-escalation study of selumetinib in combination with docetaxel or dacarbazine in patients with advanced solid tumors.

BACKGROUND: The RAS/RAF/MEK/ERK pathway is constitutively activated in many cancers. Selumetinib (AZD6244, ARRY-142886) is an oral, potent and highly selective, allosteric MEK1/2 inhibitor with a short half-life that has shown clinical activity as monotherapy in phase I and II studies of advanced cancer. Preclinical data suggest that selumetinib may enhance the activity of chemotherapeutic agents. We assessed the safety, tolerability, and pharmacokinetics (PK) of selumetinib (AZD6244, ARRY-142886) in combination with docetaxel or dacarbazine in patients with advanced solid tumors. METHODS: This study was a phase I, open-label, multicenter study in patients aged ≥18 years with advanced solid tumors who were candidates for docetaxel or dacarbazine treatment. Part A of the study (dose escalation) evaluated safety, tolerability, PK, and maximum tolerated dose (MTD) of selumetinib twice daily (BID) with docetaxel 75 mg/m2 or dacarbazine 1000 mg/m2 administered every 21 days. Patients receiving docetaxel could be administered primary prophylactic granulocyte-colony stimulating factor according to standard guidelines. Part B of the study (dose expansion) further evaluated safety, tolerability, and PK in 12 additional patients at the MTD combinations determined in part A. RESULTS: A total of 35 patients received selumetinib plus docetaxel, and 25 received selumetinib plus dacarbazine. The MTD of selumetinib was 75 mg BID in combination with either docetaxel (two dose-limiting toxicity [DLT] events: neutropenia with fever, and thrombocytopenia) or dacarbazine (one DLT event: thrombocytopenia). Common adverse events occurring with each treatment combination were diarrhea, peripheral/periorbital edema, fatigue, and nausea. PK parameters for selumetinib and docetaxel or dacarbazine were similar when administered alone or in combination. Partial responses were reported in 6/35 patients receiving selumetinib plus docetaxel and 4/25 patients receiving selumetinib plus dacarbazine. CONCLUSIONS: The combinations of selumetinib plus docetaxel and selumetinib plus dacarbazine demonstrated manageable safety and tolerability profiles and preliminary signs of clinical activity in patients with advanced solid tumors. TRIAL REGISTRATION: ClinicalTrials.gov NCT00600496; registered 8 July 2009.

Clinical efficacy of a RAF inhibitor needs broad target blockade in BRAF-mutant melanoma.

B-RAF is the most frequently mutated protein kinase in human cancers. The finding that oncogenic mutations in BRAF are common in melanoma, followed by the demonstration that these tumours are dependent on the RAF/MEK/ERK pathway, offered hope that inhibition of B-RAF kinase activity could benefit melanoma patients. Herein, we describe the structure-guided discovery of PLX4032 (RG7204), a potent inhibitor of oncogenic B-RAF kinase activity. Preclinical experiments demonstrated that PLX4032 selectively blocked the RAF/MEK/ERK pathway in BRAF mutant cells and caused regression of BRAF mutant xenografts. Toxicology studies confirmed a wide safety margin consistent with the high degree of selectivity, enabling Phase 1 clinical trials using a crystalline formulation of PLX4032 (ref. 5). In a subset of melanoma patients, pathway inhibition was monitored in paired biopsy specimens collected before treatment initiation and following two weeks of treatment. This analysis revealed substantial inhibition of ERK phosphorylation, yet clinical evaluation did not show tumour regressions. At higher drug exposures afforded by a new amorphous drug formulation, greater than 80% inhibition of ERK phosphorylation in the tumours of patients correlated with clinical response. Indeed, the Phase 1 clinical data revealed a remarkably high 81% response rate in metastatic melanoma patients treated at an oral dose of 960 mg twice daily. These data demonstrate that BRAF-mutant melanomas are highly dependent on B-RAF kinase activity.

Survival in BRAF V600-mutant advanced melanoma treated with vemurafenib.

BACKGROUND: Approximately 50% of melanomas harbor activating (V600) mutations in the serine-threonine protein kinase B-RAF (BRAF). The oral BRAF inhibitor vemurafenib (PLX4032) frequently produced tumor regressions in patients with BRAF V600-mutant metastatic melanoma in a phase 1 trial and improved overall survival in a phase 3 trial. METHODS: We designed a multicenter phase 2 trial of vemurafenib in patients with previously treated BRAF V600-mutant metastatic melanoma to investigate the efficacy of vemurafenib with respect to overall response rate (percentage of treated patients with a tumor response), duration of response, and overall survival. The primary end point was the overall response rate as ascertained by the independent review committee; overall survival was a secondary end point. RESULTS: A total of 132 patients had a median follow-up of 12.9 months (range, 0.6 to 20.1). The confirmed overall response rate was 53% (95% confidence interval [CI], 44 to 62; 6% with a complete response and 47% with a partial response), the median duration of response was 6.7 months (95% CI, 5.6 to 8.6), and the median progression-free survival was 6.8 months (95% CI, 5.6 to 8.1). Primary progression was observed in only 14% of patients. Some patients had a response after receiving vemurafenib for more than 6 months. The median overall survival was 15.9 months (95% CI, 11.6 to 18.3). The most common adverse events were grade 1 or 2 arthralgia, rash, photosensitivity, fatigue, and alopecia. Cutaneous squamous-cell carcinomas (the majority, keratoacanthoma type) were diagnosed in 26% of patients. CONCLUSIONS: Vemurafenib induces clinical responses in more than half of patients with previously treated BRAF V600-mutant metastatic melanoma. In this study with a long follow-up, the median overall survival was approximately 16 months. (Funded by Hoffmann-La Roche; ClinicalTrials.gov number, NCT00949702.).

Combined BRAF and MEK inhibition in melanoma with BRAF V600 mutations.

BACKGROUND: Resistance to therapy with BRAF kinase inhibitors is associated with reactivation of the mitogen-activated protein kinase (MAPK) pathway. To address this problem, we conducted a phase 1 and 2 trial of combined treatment with dabrafenib, a selective BRAF inhibitor, and trametinib, a selective MAPK kinase (MEK) inhibitor. METHODS: In this open-label study involving 247 patients with metastatic melanoma and BRAF V600 mutations, we evaluated the pharmacokinetic activity and safety of oral dabrafenib (75 or 150 mg twice daily) and trametinib (1, 1.5, or 2 mg daily) in 85 patients and then randomly assigned 162 patients to receive combination therapy with dabrafenib (150 mg) plus trametinib (1 or 2 mg) or dabrafenib monotherapy. The primary end points were the incidence of cutaneous squamous-cell carcinoma, survival free of melanoma progression, and response. Secondary end points were overall survival and pharmacokinetic activity. RESULTS: Dose-limiting toxic effects were infrequently observed in patients receiving combination therapy with 150 mg of dabrafenib and 2 mg of trametinib (combination 150/2). Cutaneous squamous-cell carcinoma was seen in 7% of patients receiving combination 150/2 and in 19% receiving monotherapy (P=0.09), whereas pyrexia was more common in the combination 150/2 group than in the monotherapy group (71% vs. 26%). Median progression-free survival in the combination 150/2 group was 9.4 months, as compared with 5.8 months in the monotherapy group (hazard ratio for progression or death, 0.39; 95% confidence interval, 0.25 to 0.62; P<0.001). The rate of complete or partial response with combination 150/2 therapy was 76%, as compared with 54% with monotherapy (P=0.03). CONCLUSIONS: Dabrafenib and trametinib were safely combined at full monotherapy doses. The rate of pyrexia was increased with combination therapy, whereas the rate of proliferative skin lesions was nonsignificantly reduced. Progression-free survival was significantly improved. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01072175.).

Prolonged survival of a patient with metastatic leptomeningeal melanoma treated with BRAF inhibition-based therapy: a case report.

BACKGROUND: Leptomeningeal metastasis of melanoma is a devastating complication with a grave prognosis, and there are no known effective standard treatments. Although selective BRAF inhibitors have demonstrated a significant clinical activity in patients with metastatic melanoma harboring a BRAF mutation, the clinical benefit of BRAF inhibitor-based therapy in leptomeningeal disease is not clear. CASE PRESENTATION: We present a case of prolonged survival of a patient with BRAF V600E-mutant leptomeningeal disease who was treated with vemurafenib followed by whole brain radiation and a combination of dabrafenib and trametinib. Both vemurafenib and the sequential treatment of radiation and dabrafenib/trametinib led to regression of the leptomeningeal disease, and the patient survived for 19 months after the diagnosis of the leptomeningeal disease. CONCLUSION: This case suggests a possible clinically meaningful benefit of BRAF inhibitor-based therapy and a need for close investigation of this therapeutic approach in patients with this devastating disease.

Next generation sequencing of exceptional responders with BRAF-mutant melanoma: implications for sensitivity and resistance.

BACKGROUND: Patients with BRAF mutation-positive advanced melanoma respond well to matched therapy with BRAF or MEK inhibitors, but often quickly develop resistance. METHODS: Tumor tissue from ten patients with advanced BRAF mutation-positive melanoma who achieved partial response (PR) or complete response (CR) on BRAF and/or MEK inhibitors was analyzed using next generation sequencing (NGS) assay. Genomic libraries were captured for 3230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to average median depth of 734X with 99% of bases covered >100X. RESULTS: Three of the ten patients (median number of prior therapies = 2) attained prolonged CR (duration = 23.6+ to 28.7+ months); seven patients achieved either a PR or a short-lived CR. One patient who achieved CR ongoing at 28.7+ months and had tissue available close to the time of initiating BRAF inhibitor therapy had only a BRAF mutation. Abnormalities in addition to BRAF mutation found in other patients included: mutations in NRAS, APC and NF1; amplifications in BRAF, aurora kinase A, MYC, MITF and MET; deletions in CDKN2A/B and PAX5; and, alterations in RB1 and ATM. Heterogeneity between patients and molecular evolution within patients was noted. CONCLUSION: NGS identified potentially actionable DNA alterations that could account for resistance in patients with BRAF mutation-positive advanced melanoma who achieved a PR or CR but whose tumors later progressed. A subset of patients with advanced melanoma may harbor only a BRAF mutation and achieve a durable CR on BRAF pathway inhibitors.

Dabrafenib.

Dabrafenib was developed as a highly specific reversible inhibitor of V600-mutant BRAF kinase, an oncogenic mutation driving proliferation in many different types of aggressive tumors. Metastatic melanoma has a high prevalence of V600-mutant BRAF, and clinical trials showed that dabrafenib improved response rates and median progression-free survival in patients with V600E BRAF mutations, including those with brain metastasis. Preliminary results suggest that dabrafenib may also have some role in non-melanoma V600-mutant solid tumors; however, more studies are needed. With a well-tolerated toxicity profile and few drug interactions, dabrafenib is effective as a monotherapy; however, resistance eventually develops in most patients after persistent exposure to the drug. Current research focuses on combination strategies with dabrafenib to not only improve response rates but also overcome resistance.