Phase II study of apatinib combined with temozolomide in patients with advanced melanoma after failure of immunotherapy

Evolving cancer resistance to anti-PD-1/PD-L1 antibodies in melanoma: Comprehensive insights with future prospects

Immunotherapy has transformed the treatment of advanced melanoma. However, up to two-thirds of patients experience disease progression after initially achieving a response to immunotherapy. Furthermore, most research has focused on cutaneous melanoma rather than acral or mucosal melanoma, although the latter predominates in Asian populations. In this review, we examine and summarize current definitions of resistance to immunotherapy and the epidemiology of resistance to PD-1 inhibition. We also review the available literature on molecular mechanisms of resistance, including how the tumor mutational landscape and tumor microenvironments of immunotherapy-resistant acral and mucosal melanomas may influence resistance. Finally, we review strategies for overcoming resistance to PD-1 inhibition and summarize completed studies and ongoing clinical trials. Our review highlights that improving the understanding of resistance mechanisms, optimizing existing therapies and further studying high-risk populations would maximize the potential of immunotherapy and result in optimized treatment outcomes for patients with melanoma.

Recent advances in tyrosine kinase inhibitors VEGFR 1-3 for the treatment of advanced metastatic melanoma

INTRODUCTION

Increasing evidence from preclinical and clinical studies suggests the role of vascular endothelial growth factor (VEGF) signaling in melanoma progression, response to therapy, and overall survival. Moreover, the discovery of the potential involvement of the VEGF pathway in resistance to immunotherapy has led to new clinical trials with VEGFR inhibitors.

AREAS COVERED

We have reviewed recent literature, mainly published within the last 5 years, on VEGFR-targeted treatments for advanced melanoma, including mucosal, acral, and uveal melanoma. The VEGFR inhibitors were used as a single therapy or combined with either immunotherapy or chemotherapy, and they were employed in treatment for KIT-mutated cutaneous melanoma and for patients with brain metastases.

EXPERT OPINION

Trials involving monotherapy have been unsuccessful in demonstrating meaningful efficacy. Despite some activity, the combination of VEGFR-targeting tyrosine kinase inhibitors (TKIs) with immune checkpoint inhibitors (ICI) in patients with ICI-resistant melanoma, the combination did not significantly improve outcomes compared to anti-PD-1 monotherapy in the first-line settings. On the contrary, some patients with mucosal, acral or KIT-mutant melanoma may benefit from TKI-based therapies. Further studies focused on biomarker discovery and randomized trials are necessary to better understand the role of VEGFR1-3 as a therapeutic target in melanoma.

Prediction of survival and immunotherapy response by the combined classifier of G protein-coupled receptors and tumor microenvironment in melanoma

BACKGROUND

Melanoma is the deadliest form of skin tumor, and G protein-coupled receptors (GPCRs) play crucial roles in its carcinogenesis. Furthermore, the tumor microenvironment (TME) affects the overall survival (OS) and the response to immunotherapy. The combination of GPCRs and TME from a multi-omics perspective may help to predict the survival of the melanoma patients and their response to immunotherapy.

METHODS

Bulk-seq, single-cell RNA sequencing (scRNA-seq), gene mutations, immunotherapy responses, and clinicopathologic feature data were downloaded from public databases, and prognostic GPCRs and immune cells were screened using multiple machine learning algorithms. The expression levels of GPCRs were detected using real-time quantitative polymerase chain reaction (qPCR) in A375 and HaCaT cell lines. The GPCR-TME classifier was constructed and verified using different cohorts and multi-omics. Gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), and tracking tumor immunophenotype (TIP) were used to identify the key biological pathways among the GPCR-TME subgroups. Then, tumor mutational burden (TMB), vital mutant genes, antigen presentation genes, and immune checkpoints were compared among the subgroups. Finally, the differences in immunotherapy response rates among the GPCR-TME subgroups were investigated.

RESULTS

A total of 12 GPCRs and five immune cell types were screened to establish the GPCR-TME classifier. No significant differences in the expression levels of the 12 GPCRs were found in the two cell lines. Patients with high GPCR score or low TME score had a poor OS; thus, the GPCRlow/TMEhigh subgroup had the most favorable OS. The scRNA-seq result revealed that immune cells had a higher GPCR score than tumor and stromal cells. The GPCR-TME classifier acted as an independent prognostic factor for melanoma. GSEA, WGCNA, and TIP demonstrated that the GPCRlow/TMEhigh subgroup was related to the activation and recruitment of anti-tumor immune cells and the positive regulation of the immune response. From a genomic perspective, the GPCRlow/TMEhigh subgroup had higher TMB, and different mutant genes. Ultimately, higher expression levels of antigen presentation genes and immune checkpoints were observed in the GPCRlow/TMEhigh subgroup, and the melanoma immunotherapy cohorts confirmed that the response rate was highest in the GPCRlow/TMEhigh cohort.

CONCLUSIONS

We have developed a GPCR-TME classifier that could predict the OS and immunotherapy response of patients with melanoma highly effectively based on multi-omics analysis.

Apatinib combined with camrelizumab in advanced acral melanoma patients: An open-label, single-arm phase 2 trial

BACKGROUND

At present, immune monotherapy and combination therapy has not shown satisfactory effects on acral melanoma, and still no standard treatment is available for advanced acral melanoma. Here, a phase II trial was performed to explore the safety and efficacy of apatinib combined with camrelizumab in advanced acral melanoma patients as first-line therapy (NCT03955354).

METHODS

Patients with pathologically confirmed, locally unresectable or metastatic treatment native acral melanoma received 250 mg apatinib once daily and camrelizumab 200 mg once every two weeks intravenously every 28-day cycle. The primary end-point was objective response rate and the secondary end-points were disease control rate, overall survival, progression-free survival and safety.

RESULTS

Thirty patients were recruited between January 2015 and January 2022. Among them, 21 (70.0%) had stage IV, and a median tumour burden was 50 mm (range: 11-187). Objective response rate was 24.1%, and 7 of 29 patients had an anti-tumour response, including partial response (n = 5) and complete response (n = 2). Disease control rate was 82.8%, median progression-free survival was 7.39 months (confidence interval: 3.65-9.92), and median overall survival was 13.4 months (confidence interval: 1.9-25.0). Grade 3-4 treatment-related toxicity (grade 3 50.5%; grade 4 3.3%) included transaminase elevations, proteinuria, leukocytopenia, vomiting, diarrhea and drug-induced liver injury. No treatment-related mortality occurred. The mutations of TTN, MUC16, VPS13D, ALPK2 and SCUBE1 showed significant alterations with survival outcome.

CONCLUSIONS

Apatinib combined with camrelizumab showed manageable safety profile and reasonable anti-tumour activity in advanced acral melanoma patients as first-line therapy.

Advanced Acral Melanoma Therapies: Current Status and Future Directions

Melanoma is one of the deadliest malignancies. Its incidence has been significantly increasing in most countries in recent decades. Acral melanoma (AM), a peculiar subgroup of melanoma occurring on the palms, soles, and nails, is the main subtype of melanoma in people of color and is extremely rare in Caucasians. Although great progress has been made in melanoma treatment in recent years, patients with AM have shown limited benefit from current therapies and thus consequently have worse overall survival rates. Achieving durable therapeutic responses in this high-risk melanoma subtype represents one of the greatest challenges in the field. The frequency of BRAF mutations in AM is much lower than that in cutaneous melanoma, which prevents most AM patients from receiving treatment with BRAF inhibitors. However, AM has more frequent mutations such as KIT and CDK4/6, so targeted therapy may still improve the survival of some AM patients in the future. AM may be less susceptible to immune checkpoint inhibitors because of the poor immunogenicity. Therefore, how to enhance the immune response to the tumor cells may be the key to the application of immune checkpoint inhibitors in advanced AM. Anti-angiogenic drugs, albumin paclitaxel, or interferons are thought to enhance the effectiveness of immune checkpoint inhibitors. Combination therapies based on the backbone of PD-1 are more likely to provide greater clinical benefits. Understanding the molecular landscapes and immune microenvironment of AM will help optimize our combinatory strategies.