Phase 1/2 study assessing the safety and efficacy of dabrafenib and trametinib combination therapy in Japanese patients with BRAF V600 mutation-positive advanced cutaneous melanoma

Optimal strategy in managing advanced melanoma

The advent of immune checkpoint inhibitors and combination therapy with BRAF inhibitors and MEK inhibitors has dramatically improved the prognosis of advanced melanoma. However, since acral melanoma and mucosal melanoma, which are rare in Western countries but are major subtypes of melanoma in East Asia, including Japan, have a low frequency of BRAF mutations, there are currently no treatment options other than immune checkpoint inhibitors in most such cases. Furthermore, owing to a lower tumor mutation burden, immune checkpoint inhibitors are less effective in acral and mucosal melanoma than in cutaneous melanoma. The aim of this review was to summarize the current status and future prospects for the treatment of advanced melanoma, comparing cutaneous melanoma, acral melanoma, and mucosal melanoma.

Systemic therapy for Asian patients with advanced BRAF V600-mutant melanoma in a real-world setting: A multi-center retrospective study in Japan (B-CHECK-RWD study)

BACKGROUND

Anti-PD-1-based immunotherapy is considered a preferred first-line treatment for advanced BRAF V600-mutant melanoma. However, a recent international multi-center study suggested that the efficacy of immunotherapy is poorer in Asian patients in the non-acral cutaneous subtype. We hypothesized that the optimal first-line treatment for Asian patients may be different.

METHODS

We retrospectively collected data of Asian patients with advanced BRAF V600-mutant melanoma treated with first-line BRAF/MEK inhibitors (BRAF/MEKi), anti-PD-1 monotherapy (Anti-PD-1), and nivolumab plus ipilimumab (PD-1/CTLA-4) between 2016 and 2021 from 28 institutions in Japan.

RESULTS

We identified 336 patients treated with BRAF/MEKi (n = 236), Anti-PD-1 (n = 64) and PD-1/CTLA-4 (n = 36). The median follow-up duration was 19.9 months for all patients and 28.6 months for the 184 pa tients who were alive at their last follow-up. For patients treated with BRAF/MEKi, anti-PD-1, PD-1/CTLA-4, the median ages at baseline were 62, 62, and 53 years (p = 0.03); objective response rates were 69%, 27%, and 28% (p < 0.001); median progression-free survival (PFS) was 14.7, 5.4, and 5.8 months (p = 0.003), and median overall survival (OS) was 34.6, 37.0 months, and not reached, respectively (p = 0.535). In multivariable analysis, hazard ratios (HRs) for PFS of Anti-PD-1 and PD-1/CTLA-4 compared with BRAF/MEKi were 2.30 (p < 0.001) and 1.38 (p = 0.147), and for OS, HRs were 1.37 (p = 0.111) and 0.56 (p = 0.075), respectively. In propensity-score matching, BRAF/MEKi showed a tendency for longer PFS and equivalent OS with PD-1/CTLA-4 (HRs for PD-1/CTLA-4 were 1.78 [p = 0.149]) and 1.03 [p = 0.953], respectively). For patients who received second-line treatment, BRAF/MEKi followed by PD-1/CTLA-4 showed poor survival outcomes.

CONCLUSIONS

The superiority of PD-1/CTLA-4 over BRAF/MEKi appears modest in Asian patients. First-line BRAF/MEKi remains feasible, but it is difficult to salvage at progression. Ethnicity should be considered when selecting systemic therapies until personalized biomarkers are available in daily practice. Further studies are needed to establish the optimal treatment sequence for Asian patients.

Final analysis of a post-marketing surveillance study of dabrafenib and trametinib combination therapy in Japanese patients with unresectable malignant melanoma with BRAF V600 mutation

Targeted therapy with a combination of dabrafenib and trametinib has been developed and widely used for treatment of melanoma. However, data regarding its safety and efficacy in Japanese patients with malignant melanoma are limited. A post-marketing surveillance (PMS) study was conducted to investigate the safety and efficacy of combination therapy in a Japanese clinical setting with a surveillance period of June 2016 to March 2022; 326 patients with unresectable malignant melanoma with BRAF mutation were enrolled. The interim results were published in July 2020. Herein, we report the results of the final analysis based on the data collected until the completion of the PMS study. The safety analysis population included 326 patients, the majority of whom had stage IV disease (79.14%) and Eastern Cooperative Oncology Group performance status 0 or 1 (85.28%). All patients were treated with the approved dose of dabrafenib, while 99.08% were treated with the approved dose of trametinib. Adverse events (AEs) occurred in 282 patients (86.50%) and the major AEs (incidence ≥5%) were pyrexia (47.85%), malignant melanoma (33.44%), hepatic function abnormal (9.82%), rash and blood creatine phosphokinase increased (8.59% each), malaise (6.44%), nausea (5.52%), and diarrhea and rhabdomyolysis (5.21% each). The incidences rates of adverse drug reactions of safety specifications were 45.71% for pyrexia, 15.95% for hepatic impairment, 12.58% for rhabdomyolysis, 4.60% for cardiac disorders, and 3.07% for eye disorders. In the efficacy analysis population of 318 patients, the objective response rate was 58.18% (95% confidence interval [CI] 52.54%-63.66%). The progression-free survival rates at 90, 180, and 360 days were 88.14% (95% CI 84.00%-91.26%), 69.53% (63.85%-74.50%), and 52.07% (45.71%-58.03%), respectively. Consistent with previous interim results, no new safety or efficacy concerns were observed in this final analysis of a PMS study conducted in a Japanese real-world clinical setting.

Immunotherapy Options for Acral Melanoma, A fast-growing but Neglected Malignancy

Melanoma is the deadliest form of skin cancer. It is classified as cutaneous and non-cutaneous, with the former characterized by developing in sun-exposed areas of the skin, UV-light radiation being its most important risk factor and ordinarily affecting fair skin populations. In recent years, the incidence of melanoma has been increasing in populations with darker complexion, for example, Hispanics, in which acral melanoma is highly prevalent. The WHO estimates that the incidence and mortality of melanoma will increase by more than 60% by 2040, particularly in low/medium income countries. Acral melanoma appears in the palms, soles and nails, and because of these occult locations, it is often considered different from other cutaneous melanomas even though it also originates in the skin. Acral melanoma is very rare in Caucasian populations and is often not included from genetic analysis and clinical trials. In this review, we present the worldwide epidemiology of acral melanoma; we summarize its genetic characterization and point out important signaling pathways for targeted therapy. We also discuss how genetic analyses have shown that acral melanoma carries a sufficient mutational load and neoantigen formation to be targeted by the immune system, arguing for a potential benefit with novel immunotherapeutic strategies, alone or combined with targeted therapy. This is important because chemotherapy remains the first-line treatment in non-developed nations despite a disheartening response. In summary, the increased incidence and mortality of acral melanoma in low/medium income countries calls for increasing our knowledge about its nature and therapeutic options and leveling off the asymmetric research conducted primarily on Caucasian populations.

Simultaneous and rapid determination of 12 tyrosine kinase inhibitors by LC-MS/MS in human plasma: Application to therapeutic drug monitoring in patients with non-small cell lung cancer

In recent years, more than 50 tyrosine kinase inhibitors (TKIs) was indicated against numerous cancers, especially outstanding advantages in the treatment of non-small cell lung cancer (NSCLC), and several studies have shown that therapeutic drug monitoring (TDM) of TKIs can improve treatment efficacy and safety. The present study aimed to develop and validate a LC-MS/MS method for the TDM of 12 TKIs (gefitinib, erlotinib, afatinib, dacomitinib, icotinib, osimertinib, crizotinib, ceritinib, alectinib, dabrafenib, trametinib, anlotinib) in patients with NSCLC. The analytes of interest and internal standard were extracted from human plasma. Salting-out assisted liquid-liquid extraction (SALLE) with 5 M ammonium acetate solution was optimized for method validation and compared to simple protein precipitation (PPT). Chromatographic separation was conducted on Waters X bridge C18 column (100 × 4.6 mm, 3.5 μm) using a gradient elution of acetonitrile/5mM ammonium acetate in pure water with 0.1% (v/v) formic acid at 40 °C within 6 min. The total flow was maintained at 1 mL/min, 30% of the post column flow was split into the mass spectrometer and the rest to waste via a 3-way tee. The mass analysis was performed by positive ion electrospray ionization (ESI) in multiple-reaction monitoring (MRM) mode. The assay was validated based on the guidelines on bioanalytical methods by FDA. This quantification method was proved to be satisfactory in selectivity, accuracy, precision, linearity (r² > 0.995), recovery, matrix effect and stability and the accuracy was further assessed in plasma with a degree of hemolysis of 4%. The described method to simultaneously quantify the 12 selected anticancer drugs in human plasma was successfully validated and applied to routine TDM of gefitinib, erlotinib, icotinib, osimertinib, crizotinib and anlotinib in cancer patients. TKIs plasma monitoring helps to individualize dose adjustment and manage adverse effects in NSCLC patients.

Recent advances in molecular targeted therapy for unresectable and metastatic BRAF-mutated melanoma

The clinical outcome of BRAF-mutated advanced melanoma has been improved by both molecular targeted therapies and immune checkpoint inhibitors. Long-term follow-up data reveal durable clinical responses in patients receiving first-line combinations of BRAF inhibitors plus MEK inhibitors, particularly those showing a complete response. Clinical outcomes are also associated with the lactate dehydrogenase levels and the number of metastatic organs. Although brain metastasis is frequently difficult to control, systemic therapy is preferred in cases with small and asymptomatic brain metastases associated with progressive extra-cranial disease. Control of intra-cranial disease with BRAF inhibitors plus MEK inhibitors is comparable with that of immune checkpoint inhibitors, although immune checkpoint inhibitors are superior to targeted therapies with respect to survival. The BRAF inhibitors plus MEK inhibitors regimen is well-tolerated, and toxicities are usually manageable and reversible, but differ according to the specific regimen used. Guidelines in the United States, Europe, and Japan recommend targeted therapy for patients who need early tumor responses. A meta-analysis of retrospective data shows that the baseline lactate dehydrogenase level is significantly higher in patients treated with BRAF inhibitors plus MEK inhibitors than in those treated with immune checkpoint inhibitors, suggesting that clinicians tend to use BRAF inhibitors plus MEK inhibitors for more advanced disease. Since there is insufficient efficacy and safety data on the use of targeted therapies for acral and mucosal melanoma, a retrospective analysis may be useful. The combination of molecular targeted therapy plus immune checkpoint inhibitors is expected to elicit further improvement. The results of several trials using combination or sequential therapies will be available in the next few years.

Effectiveness and Safety of Dabrafenib in the Treatment of 20 Chinese Children with BRAFV600E-Mutated Langerhans Cell Histiocytosis

Purpose

We sought to investigate the effectiveness and safety of dabrafenib in children with BRAF^V600E-mutated Langerhans cell histiocytosis (LCH).

Materials and Methods

A retrospective analysis was performed on 20 children with BRAF^V600E-mutated LCH who were treated with dabrafenib.

Results

The median age at which the patients started taking dabrafenib was 2.3 years old (range, 0.6 to 6.5 years). The ratio of boys to girls was 2.3:1. The median follow-up time was 30.8 months (range, 18.9 to 43.6 months). There were 14 patients (70%) in the risk organ (RO)⁺ group and six patients (30%) in the RO⁻ group. All patients were initially treated with traditional chemotherapy and then shifted to targeted therapy due to poor control of LCH or intolerance to chemotherapy. The overall objective response rate and the overall disease control rate were 65% and 75%, respectively. During treatment, circulating levels of cell-free BRAF^V600E (cfBRAF^V600E) became negative in 60% of the patients within a median period of 3.0 months (range, 1.0 to 9.0 months). Grade 2 or 3 adverse effects occurred in five patients.

Conclusion

Some children with BRAF^V600E-mutated LCH may benefit from monotherapy with dabrafenib, especially high-risk patients with concomitant hemophagocytic lymphohistiocytosis and intolerance to chemotherapy. The safety of dabrafenib is notable. A prospective study with a larger sample size is required to determine the optimal dosage and treatment duration.

The incidence and risk of cutaneous toxicities associated with dabrafenib in melanoma patients: a systematic review and meta-analysis

OBJECTIVE

Dabrafenib, an inhibitor of mutated BRAF, has significant clinical activity in melanoma patients but is linked to a spectrum of cutaneous toxicities. Thus, our meta-analysis was conducted to evaluate the type, incidence and risks of dermatological toxicities from dabrafenib.

METHODS

Systematic searches were performed using electronic databases such as Embase and PubMed and conference abstracts published by the American Society of Clinical Oncology. Eligible studies were limited to prospective phase I, II and III clinical trials and expanded-access (ie, outside clinical trials) programmes of melanoma patients receiving dabrafenib monotherapy (150 mg, twice daily) or combination therapy of dabrafenib (150 mg, twice daily) plus trametinib (2 mg, once daily). The outcomes were mainly the incidence rate and risk of all-grade cutaneous toxicities associated with dabrafenib in melanoma patients.

RESULTS

Twenty trials comprising a total of 3359 patients were included in the meta-analysis. The meta-analysis showed that the overall incidence of all-grade rash for melanoma patients assigned dabrafenib was 30.00% (95% CI 0.07 to 0.71), cutaneous squamous-cell carcinoma (cSCC) 16.00% (95% CI 0.11 to 0.24), alopecia 21% (95% CI 0.11 to 0.37), keratoacanthoma (KA) 20.00% (95% CI 0.12 to 0.31), hyperkeratosis (HK) 14.00% (95% CI 0.09 to 0.22) and pruritus 8.00% (95% CI 0.05 to 0.12). All-grade rash occurred in 19.00% (95% CI 0.15 to 0.25), cSCC in 10.00% (95% CI 0.04 to 0.22), alopecia in 6.00% (95% CI 0.03 to 0.12), KA in 6.00% (95% CI 0.04 to 0.09) and pruritus in 2/1265 patients assigned dabrafenib plus trametinib. The summary risk ratio (RR) showed that the combination of dabrafenib with trametinib versus dabrafenib was associated with a significantly increased risk of all-grade rash (RR 1.35, 95% CI 1.01 to 1.80) and a decreased risk of cSCC (RR 0.40, 95% CI 0.18 to 0.89), alopecia (RR 0.19, 95% CI 0.12 to 0.30) and HK (RR 0.25, 95% CI 0.10 to 0.62).

CONCLUSION

In summary, the most frequent cutaneous adverse reactions from dabrafenib were rash, cSCC, alopecia, KA, HK and pruritus. There was a significantly decreased risk of cSCC, alopecia and HK with the combination of dabrafenib with trametinib versus dabrafenib alone. Clinicians should be aware of these risks and perform regular clinical monitoring.

Interim analysis for post-marketing surveillance of dabrafenib and trametinib combination therapy in Japanese patients with unresectable and metastatic melanoma with BRAF V600 mutation

Purpose

To investigate the safety and efficacy of dabrafenib and trametinib combination therapy for BRAF V600 mutation-positive unresectable and metastatic melanoma in over 100 Japanese patients of a real-world clinical setting.

Patients

The surveillance period of interim post-marketing surveillance (PMS) analysis was from June 2016 to November 2018, and 112 patients with unresectable and metastatic BRAF V600 melanoma who received dabrafenib and trametinib were enrolled.

Results

The safety analysis set included 112 patients whom almost all patients had stage IV disease (n = 97, 86.61%) with an Eastern Cooperative Oncology Group performance status 0 or 1 (n = 102, 91.07%), and mean (standard deviation) lactate dehydrogenase level was 354.3 (456.4) U/L (n = 105) at baseline. Median daily dose of dabrafenib was 300.0 mg/day (118–300), and median daily dose of trametinib was 2.00 mg/day (1.0–4.0). Adverse drug reactions (ADRs) were reported in 84 patients (75%), and common ADRs (incidence ≥ 5%) were pyrexia (n = 49, 43.75%), hepatic function abnormal (n = 11, 9.82%), rash and blood creatine phosphokinase increased (n = 9 each, 8.04%), and erythema nodosum (n = 6, 5.36%). Majority of ADRs reported in this study were consistent with that reported in previous trials. In the efficacy analysis set of 110 patients, the objective response rate was 55.45% (95% confidence interval 45.67–64.93%), and median progression-free survival was 384.0 days (251.0 days-not reached).

Conclusions

No new safety or efficacy concerns were observed in this interim PMS analysis in Japanese patients with unresectable and metastatic melanoma with BRAF gene mutation who received dabrafenib and trametinib combination therapy.

Electronic supplementary material

The online version of this article (10.1007/s10147-020-01737-3) contains supplementary material, which is available to authorized users.

Surface polymer imprinted optical fibre sensor for dose detection of dabrafenib

Dabrafenib is one of the most widely used of the new generation of targeted anti-cancer drugs. However, its therapeutic window varies for different patients and so there is an unmet need for methods to monitor the dose of drug which the patient receives and at the specific site where it acts. In the case of cancers, it is critical to measure the concentration of drug not just in the bloodstream overall, but in or near tumours, as these will not be the same over multiple time periods. A novel sensor based on an optical fibre long period grating (LPG) modified with a molecular imprinted polymer (MIP) has been developed with the ultimate aim of achieving minimally invasive measurements of Dabrafenib at the tumour site. A molecularly imprinted polymer specific for Dabrafenib was coated on a methacryloylalkoxysilane-functionalised optical fibre long period grating. In vitro experimental results demonstrate that the Dabrafenib sensitivity is 15.2 pm (μg mL^-1)^-1 (R² = 0.993) with a limit of detection (LoD) of 74.4 μg mL^-1 in serum solution. Moreover, the proposed sensor shows selective response to Dabrafenib over structurally similar 2-Aminoquinoline.

Real-world efficacy and safety data for dabrafenib and trametinib combination therapy in Japanese patients with BRAF V600 mutation-positive advanced melanoma

We conducted a retrospective investigation of the efficacy and safety of dabrafenib and trametinib combination therapy in Japanese patients with BRAF V600 mutation-positive advanced melanoma in real-world clinical practise. The study analyzed 50 patients who received dabrafenib and trametinib combination therapy for BRAF V600 mutation-positive advanced melanoma in our hospital (26 men and 24 women, aged 21-86 years, inclusive; median age, 53 years). The response rate was 72.3%, with complete response (CR) achieved in eight cases (17.0%), partial response in 26 (55.3%), stable disease in nine (19.1%) and progressive disease in four (8.5%). Median progression-free survival (PFS) was 12 months, and median overall survival (OS) was 23 months. Disease progression occurred in 29 of the 50 patients during the study period, and 25 patients died. Baseline lactate dehydrogenase and the number of organs with metastasis were important predictive factors for PFS and OS, and CR to combination therapy was a predictive factor for long-term remission. Adverse events occurred in 88% of cases; 16% were grade 3 or worse. The adverse events observed in 50% of more of patients were rash (56%) and pyrexia (52%). The efficacy of dabrafenib and trametinib combination therapy in Japanese patients was similar to that reported in global studies, and the same adverse events were generally reported; however, rash tended to occur more frequently in the patients in our study.

Multiple primary malignant neoplasms: A case report and literature review

Until recently, few cases of three or more malignant tumors in one patient have been reported. Owing to the high incidence rate of these tumors, the improvement in cancer diagnosis and treatment, and the extension of patient survival time, the incidence of reported multiple primary malignant neoplasms has gradually increased. The present study reported the case of a 57-year-old man with non-small cell lung cancer combined with B-Raf proto-oncogene serine/threonine kinase V600E mutation, gastrointestinal stromal tumors and lumbar vertebral malignant mucinous sarcoma. The pathogenesis, diagnosis and treatment of these three malignancies are discussed and previous studies are also reviewed. The aim of the study was to analyze the genetic mutations associated with multiple primary malignant tumors and to discuss whether those mutations with unknown functional significance could be used as therapeutic indicators. This case report will serve as a reference for future treatment of such patients.

Targeted Therapy and Immunotherapy for Melanoma in Japan

OPINION STATEMENT

Melanoma has several clinically and pathologically distinguishable subtypes, which also differ genetically. Mutation patterns vary among different melanoma subtypes, and efficacy of immune-checkpoint inhibitors differs depending on the subtype of melanoma. In spite of the recent revolution of systemic therapies for advanced melanoma, access to innovative agents is still restricted in many countries. This review article aimed to describe the epidemiology and current status of systemic therapies for melanoma in Japan, where melanoma is rare, but access to innovative agents is available. Acral and mucosal melanomas, which are common in Asian populations, predominantly occur in sun-protected areas and share several biological features. Both the melanomas harbor KIT mutation in approximately 15% of the cases; BRAF or NRAS mutation is found in approximately 10-15% of acral melanoma, but these mutations are less frequent in mucosal melanoma. Combined use of BRAF and MEK inhibitors is one of the standards of care for patients with advanced BRAF-mutant melanoma. In patients with melanoma harboring KIT mutation in exon 11 or 13, KIT inhibitors can be a treatment option; however, none of them have been approved in Japan. Immune-checkpoint inhibitors are expected to be less effective against acral and mucosal melanomas because their somatic mutation burden is lower than those in non-acral cutaneous melanomas. A recently completed phase II trial of nivolumab and ipilimumab combination therapy in 30 Japanese patients with melanoma, including seven with acral and 12 with mucosal melanoma, demonstrated an objective response rate of 43%. Regarding oncolytic viruses, canerpaturev (C-REV, also known as HF10) and talimogene laherparepvec (T-VEC) are currently under review in early phase trials. In the adjuvant setting, dabrafenib plus trametinb combination, nivolumab monotherapy, and pembrolizumab monotherapy were approved in July, August, and December 2018 in Japan, respectively. However, most of the adjuvant phase III trials excluded patients with mucosal melanoma. A phase III trial of adjuvant therapy with locoregional interferon (IFN)-β versus surgery alone is ongoing in Japan (JCOG1309, J-FERON), in which IFN-β is injected directly into the site of the primary tumor postoperatively, so that it would be drained through the untreated lymphatic route to the regional node basin. After the recent approval of these new agents, the JCOG1309 trial will be revised to focus on patients with stage II disease. In conclusion, acral and mucosal melanomas have been treated based on the available medical evidence for the treatment of non-acral cutaneous melanomas. Considering the differences in genetic backgrounds and therapeutic efficacy of immunotherapy, specialized therapeutic strategies for these subtypes of melanoma should be established in the future.

Combined inhibition of MEK and PI3K pathways overcomes acquired resistance to EGFR-TKIs in non-small cell lung cancer

Compensatory activation of the signal transduction pathways is one of the major obstacles for the targeted therapy of non-small cell lung cancer (NSCLC). Herein, we present the therapeutic strategy of combined targeted therapy against the MEK and phosphoinositide-3 kinase (PI3K) pathways for acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in NSCLC. We investigated the efficacy of combined trametinib plus taselisib therapy using experimentally established EGFR-TKI-resistant NSCLC cell lines. The results showed that the feedback loop between MEK/ERK and PI3K/AKT pathways had developed in several resistant cell lines, which caused the resistance to single-agent treatment with either inhibitor alone. Meanwhile, the combined therapy successfully regulated the compensatory activation of the key intracellular signals and synergistically inhibited the cell growth of those cells in vitro and in vivo. The resistance mechanisms for which the dual kinase inhibitor therapy proved effective included (MET) mesenchymal-epithelial transition factor amplification, induction of epithelial-to-mesenchymal transition (EMT) and EGFR T790M mutation. In further analysis, the combination therapy induced the phosphorylation of p38 MAPK signaling, leading to the activation of apoptosis cascade. Additionally, long-term treatment with the combination therapy induced the conversion from EMT to mesenchymal-to-epithelial transition in the resistant cell line harboring EMT features, restoring the sensitivity to EGFR-TKI. In conclusion, our results indicate that the combined therapy using MEK and PI3K inhibitors is a potent therapeutic strategy for NSCLC with the acquired resistance to EGFR-TKIs.