IMPemBra: a phase 2 study comparing pembrolizumab with intermittent/short-term dual MAPK pathway inhibition plus pembrolizumab in patients with melanoma harboring the BRAFV600 mutation

BACKGROUND

Continuous combination of MAPK pathway inhibition (MAPKi) and anti-programmed death-(ligand) 1 (PD-(L)1) showed high response rates, but only limited improvement in progression-free survival (PFS) at the cost of a high frequency of treatment-related adverse events (TRAE) in patients with BRAF^V600-mutated melanoma. Short-term MAPKi induces T-cell infiltration in patients and is synergistic with anti-programmed death-1 (PD-1) in a preclinical melanoma mouse model. The aim of this phase 2b trial was to identify an optimal regimen of short-term MAPKi with dabrafenib plus trametinib in combination with pembrolizumab.

METHODS

Patients with treatment-naïve BRAF^V600E/K-mutant advanced melanoma started pembrolizumab 200 mg every 3 weeks. In week 6, patients were randomized to continue pembrolizumab only (cohort 1), or to receive, in addition, intermittent dabrafenib 150 mg two times per day plus trametinib 2 mg one time per day for two cycles of 1 week (cohort 2), two cycles of 2 weeks (cohort 3), or continuously for 6 weeks (cohort 4). All cohorts continued pembrolizumab for up to 2 years. Primary endpoints were safety and treatment-adherence. Secondary endpoints were objective response rate (ORR) at week 6, 12, 18 and PFS.

RESULTS

Between June 2016 and August 2018, 33 patients with advanced melanoma have been included and 32 were randomized. Grade 3-4 TRAE were observed in 12%, 12%, 50%, and 63% of patients in cohort 1, 2, 3, and 4, respectively. All planned targeted therapy was given in 88%, 63%, and 38% of patients in cohort 2, 3, and 4. ORR at week 6, 12, and 18 were 38%, 63%, and 63% in cohort 1; 25%, 63%, and 75% in cohort 2; 25%, 50%, and 75% in cohort 3; and 0%, 63%, and 50% in cohort 4. After a median follow-up of 43.5 months, median PFS was 10.6 months for pembrolizumab monotherapy and not reached for patients treated with pembrolizumab and intermittent dabrafenib and trametinib (p=0.17). The 2-year and 3-year landmark PFS were both 25% for cohort 1, both 63% for cohort 2, 50% and 38% for cohort 3 and 75% and 60% for cohort 4.

CONCLUSIONS

The combination of pembrolizumab plus intermittent dabrafenib and trametinib seems more feasible and tolerable than continuous triple therapy. The efficacy is promising and appears to be favorable over pembrolizumab monotherapy.

TRIAL REGISTRATION NUMBER

NCT02625337.

Managing Metastatic Melanoma in 2022: A Clinical Review

Cutaneous melanoma remains the most lethal of the primary cutaneous neoplasms, and although the incidence of primary melanoma continues to rise, the mortality from metastatic disease remains unchanged, in part through advances in treatment. Major developments in immunomodulatory and targeted therapies have provided robust improvements in response and survival trends that have transformed the clinical management of patients with metastatic melanoma. Additional advances in immunologic and cancer cell biology have contributed to further optimization in (1) risk stratification, (2) prognostication, (3) treatment, (4) toxicity management, and (5) surveillance approaches for patients with an advanced melanoma diagnosis. In this review, we provide a comprehensive overview of the historical and future advances regarding the translational and clinical implications of advanced melanoma and share multidisciplinary recommendations to aid clinicians in the navigation of current treatment approaches for a variety of patient cohorts.

KEYNOTE-022 part 3: a randomized, double-blind, phase 2 study of pembrolizumab, dabrafenib, and trametinib in BRAF-mutant melanoma

Background

In the KEYNOTE-022 study, pembrolizumab with dabrafenib and trametinib (triplet) improved progression-free survival (PFS) versus placebo with dabrafenib and trametinib (doublet) without reaching statistical significance. Mature results on PFS, duration of response (DOR), and overall survival (OS) are reported.

Methods

The double-blind, phase 2 part of KEYNOTE-022 enrolled patients with previously untreated BRAF^V600E/K-mutated advanced melanoma from 22 sites in seven countries. Patients were randomly assigned 1:1 to intravenous pembrolizumab (200 mg every 3 weeks) or placebo plus dabrafenib (150 mg orally two times per day) and trametinib (2 mg orally one time a day). Primary endpoint was PFS. Secondary endpoints were objective response rate, DOR, and OS. Efficacy was assessed in the intention-to-treat population, and safety was assessed in all patients who received at least one dose of study drug. This analysis was not specified in the protocol.

Results

Between November 30, 2015 and April 24, 2017, 120 patients were randomly assigned to triplet (n=60) or doublet (n=60) therapy. With 36.6 months of follow-up, median PFS was 16.9 months (95% CI 11.3 to 27.9) with triplet and 10.7 months (95% CI 7.2 to 16.8) with doublet (HR 0.53; 95% CI 0.34 to 0.83). With triplet and doublet, respectively, PFS at 24 months was 41.0% (95% CI 27.4% to 54.2%) and 16.3% (95% CI 8.1% to 27.1%); median DOR was 25.1 months (95% CI 14.1 to not reached) and 12.1 months (95% CI 6.0 to 15.7), respectively. Median OS was not reached with triplet and was 26.3 months with doublet (HR 0.64; 95% CI 0.38 to 1.06). With triplet and doublet, respectively, OS at 24 months was 63.0% (95% CI 49.4% to 73.9%) and 51.7% (95% CI 38.4% to 63.4%). Grade 3–5 treatment-related adverse events (TRAEs) occurred in 35 patients (58%, including one death) receiving triplet and 15 patients (25%) receiving doublet.

Conclusion

In BRAF^V600E/K-mutant advanced melanoma, pembrolizumab plus dabrafenib and trametinib substantially improved PFS, DOR, and OS with a higher incidence of TRAEs. Interpretation of these results is limited by the post hoc nature of the analysis.

Case Report: Rechallenge With BRAF and MEK Inhibitors in Metastatic Melanoma: A Further Therapeutic Option in Salvage Setting?

Background

The combination of BRAF and MEK inhibitors represents the standard of care treatment for patients with metastatic BRAF-mutated melanoma, notwithstanding the high frequency of emergent resistance. Moreover, therapeutic options outside clinical trials are scarce when patients have progressed after both targeted therapy and therapy with immune checkpoint inhibitors. In this article, we report our experience with targeted therapy rechallenging with BRAF and MEK inhibitors in patients with metastatic BRAF-mutated melanoma after progression with kinase inhibitors and immunotherapy.

Methods

Four patients with metastatic BRAF-mutated melanoma were rechallenged with BRAF and MEK inhibitors after progression with targeted therapy and subsequent immunotherapy (checkpoint inhibitors).

Results

Two patients (one of them was heavily pretreated) had partial response over 36 months (with local treatment on oligoprogression disease) and 10 months, respectively. A third patient with multisite visceral disease and high serum levels of lactate dehydrogenase had a short-lived clinical benefit rapidly followed by massive progression of disease (early progressor). The fourth patient, currently on treatment with BRAF/MEK inhibitors, is showing a clinical benefit and radiological stable disease over 3 months of therapy. Adverse events were manageable, similar to those reported during the first targeted therapy; the treatment was better tolerated at rechallenge compared with the first treatment by two out of four patients.

Treatment Following Progression in Metastatic Melanoma: the State of the Art from Scientific Literature to Clinical Need

INTRODUCTION

In the last few years, the advent of targeted therapy and immunotherapy has improved the management and the prognosis of metastatic melanoma, but the spread of resistance mechanisms can lead to disease progression. The clinical management in this setting can be challenging because the oncologist has to decide what is the best treatment strategy among therapy beyond progression (TBP), therapy change, and the rechallenge approach. This review of the relevant scientific literature is intended to clarify which patients with progressing metastatic melanoma will benefit from continuation of ongoing therapy and which ones will not. The data are based on a total of about 4300 patients coming from the main retrospective studies in the chosen field. The article body is divided into four sections which analyze respectively the targeted therapy beyond progression, the immunotherapy beyond progression, the possible treatment sequences, and finally the rechallenge strategy.

RECENT FINDINGS

Despite the possible approaches of TBP or rechallenge, the patient may not have an optimal response and may need new therapy, which is currently missing. To broaden the pharmacological offer in the fight against melanoma, cancer research is studying new disease targets, like the NRAS, PI3K, and cKIT pathways or combination treatment of targeted therapy plus immunotherapy. Despite the limitations of this work, mainly due to the limited number of studies, their retrospective nature and the lack of comparative studies, the analysis performed allows us to draw some important conclusions: therapy beyond progression, both targeted therapy and immunotherapy, represents a valid treatment option with positive effects on disease control and survival outcomes for patients with low clinical risk, expressed as low disease burden, normal LDH levels, and good performance status; moreover, the prognosis and quality of life of these patients improve when TBP is associated with locoregional treatments. In patients with progressive metastatic melanoma and high clinical risk (high disease burden, high LDH levels, and poor performance status), it is recommended to change therapy, without ever forgetting the possibility of enrolling the patient in a clinical trial. Finally, an efficacious treatment alternative is the rechallenge strategy; this approach consists in a re-treatment with the same drug after a variable interval of discontinuation. Preliminary studies seem to have demonstrated that patients retreated with targeted therapy achieved a greater benefit if they had a low clinical risk and if the drug doublet (BRAF + MEK inhibitors) was used. On the side of immunotherapy, the rechallenge strategy produced a major benefit in patients who prior experienced a severe toxic episode.

Combining BRAF/MEK Inhibitors with Immunotherapy in the Treatment of Metastatic Melanoma

The management and prognosis of BRAF-mutant metastatic melanoma have changed drastically following the introduction of immune checkpoint inhibitors and molecularly targeted agents. These treatment options present different mechanisms of action and toxicities but also totally distinct kinetics of their response, including a "relatively" short-lasting benefit in subsets of patients treated with BRAF/MEK inhibitors and a lower response rate in patients treated with immune checkpoint inhibitors. BRAF/MEK inhibitors, when administered prior to or concurrently with immune checkpoint inhibitors, at least transiently alter some immunosuppressive parameters of the tumor microenvironment and theoretically improve sensitivity to immunotherapy. Preclinical data from mouse models with oncogene-addicted melanoma confirmed this beneficial immune/targeted synergy and supported the clinical testing of combinations of BRAF/MEK inhibitors and immune checkpoint inhibitors to improve the activity of upfront anti-melanoma therapies. The first positive phase III results were published in 2020, and triggered the discussion about the benefits, the limitations, as well as the possible implications of combining or sequencing targeted therapies with immune checkpoint inhibitors in everyday practice. Beginning from the interplay of immune/targeted agents within the melanoma microenvironment, this review outlines available information from the retrospective experience up to the late-stage randomized evidence on combinatorial treatments. Many clinical trials are currently underway exploring open questions about optimal timing, new immune biomarkers, and eligible patient subsets for these immune/targeted regimens. Awaiting these results, decision making in the first-line setting for BRAF-mutant melanoma is still guided by the patients' characteristics and the biological aspects of melanoma.

State of Melanoma: An Historic Overview of a Field in Transition

The management of melanoma significantly improved within the last 25 years. Chemotherapy was the first approved systemic therapeutic approach and resulted in a median overall of survival less than 1 year, without survival improvement in phase III trials. High-dose interferon α2b and IL-2 were introduced for resectable high-risk and advanced disease, respectively, resulting in improved survival and response rates. The anti-CTLA4 and anti-programmed death 1 monoclonal antibodies along with BRAF/MEK targeted therapies are the dominant therapeutic classes of agent for melanoma. This article provides an historic overview of the evolution of melanoma management.

Association of BRAF V600E/K Mutation Status and Prior BRAF/MEK Inhibition With Pembrolizumab Outcomes in Advanced Melanoma: Pooled Analysis of 3 Clinical Trials

Importance

The optimal sequencing of immune checkpoint inhibitors and targeted therapy for BRAF V600E/K-mutant melanoma is not well established.

Objective

To assess the association of BRAF wild-type (WT) or BRAF V600E/K-mutant status and BRAF inhibitor (BRAFi) with or without MEK inhibitor (MEKi) therapy with response to pembrolizumab.

Design, Setting, and Participants

This study is a post hoc subgroup analysis of pooled data from 3 multinational, multisite studies: KEYNOTE-001 (data cutoff September 1, 2017), KEYNOTE-002 (data cutoff May 30, 2018), and KEYNOTE-006 (data cutoff December 4, 2017). Patients included in this analysis were adults with advanced melanoma and known BRAF V600E/K tumor status who had received pembrolizumab.

Interventions

Patients received pembrolizumab in dosages of 2 mg/kg every 3 weeks, 10 mg/kg every 2 weeks, or 10 mg/kg every 3 weeks.

Main Outcomes and Measures

End points were objective response rate (ORR) and progression-free survival (PFS) assessed by Response Evaluation Criteria in Solid Tumors, version 1.1, and overall survival (OS). Objective response rates, 4-year PFS, and OS rates were compared in the following patient subgroups: BRAF WT vs BRAF V600E/K-mutant melanoma and BRAF V600E/K-mutant melanoma with vs without previous treatment with BRAFi with or without MEKi therapy.

Results

The overall study population (N = 1558) included 944 men (60.6%) and 614 women (39.4%). The mean (SD) age was 60.0 years (14.0). The ORR was 38.3% (596/1558), 4-year PFS rate was 22.0%, and 4-year OS rate was 36.9%. For patients with BRAF WT (n = 1124) and BRAF V600E/K-mutant melanoma (n = 434), ORR was 39.8% (n = 447) and 34.3% (n = 149), 4-year PFS rate was 22.9% and 19.8%, and 4-year OS rate was 37.5% and 35.1%, respectively. Patients with BRAF V600E/K-mutant melanoma who had (n = 271) vs had not (n = 163) previously received BRAFi with or without MEKi therapy had baseline characteristics with worse prognosis; ORR was 28.4% (n = 77) and 44.2% (n = 72), 4-year PFS rate was 15.2% and 27.8%, and 4-year OS rate was 26.9% and 49.3%, respectively.

Conclusions and Relevance

Results of this subgroup analysis support the use of pembrolizumab for treatment of advanced melanoma regardless of BRAF V600E/K mutation status or receipt of prior BRAFi with or without MEKi therapy.

Addressing resistance to immune checkpoint inhibitor therapy: an urgent unmet need

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of various cancers by reversing the immunosuppressive mechanisms employed by tumors to restore anticancer immunity. Although ICIs have demonstrated substantial clinical efficacy, patient response can vary in depth and duration, and many do not respond at all or eventually develop resistance. ICI resistance mechanisms can be tumor-intrinsic, related to the tumor microenvironment or patient-specific factors. Multiple resistance mechanisms may be present within one tumor subtype, or heterogeneity exists among patients with the same tumor type. Consequently, designing effective combination treatment strategies is challenging. This review will discuss ICI resistance mechanisms, and summarize findings from key preclinical and clinical trials of ICIs, to identify potential treatment strategies or pathways to overcome ICI resistance.

The Influence of Tumor Microenvironment on Immune Escape of Melanoma

The low efficiency of currently-used anti-cancer therapies poses a serious challenge, especially in the case of malignant melanoma, a cancer characterized by elevated invasiveness and relatively high mortality rate. The role of the tumor microenvironment in the progression of melanoma and its acquisition of resistance to treatment seems to be the main focus of recent studies. One of the factors that, in normal conditions, aids the organism in its fight against the cancer and, following the malignant transformation, adapts to facilitate the development of the tumor is the immune system. A variety of cell types, i.e., T and B lymphocytes, macrophages, and dendritic and natural killer cells, as well as neutrophils, support the growth and invasiveness of melanoma cells, utilizing a plethora of mechanisms, including secretion of pro-inflammatory molecules, induction of inhibitory receptors expression, or depletion of essential nutrients. This review provides a comprehensive summary of the processes regulated by tumor-associated cells that promote the immune escape of melanoma cells. The described mechanisms offer potential new targets for anti-cancer treatment and should be further studied to improve currently-employed therapies.

Evolving impact of long-term survival results on metastatic melanoma treatment

Melanoma treatment has been revolutionized over the past decade. Long-term results with immuno-oncology (I-O) agents and targeted therapies are providing evidence of durable survival for a substantial number of patients. These results have prompted consideration of how best to define long-term benefit and cure. Now more than ever, oncologists should be aware of the long-term outcomes demonstrated with these newer agents and their relevance to treatment decision-making. As the first tumor type for which I-O agents were approved, melanoma has served as a model for other diseases. Accordingly, discussions regarding the value and impact of long-term survival data in patients with melanoma may be relevant in the future to other tumor types. Current findings indicate that, depending on the treatment, over 50% of patients with melanoma may gain durable survival benefit. The best survival outcomes are generally observed in patients with favorable prognostic factors, particularly normal baseline lactate dehydrogenase and/or a low volume of disease. Survival curves from melanoma clinical studies show a plateau at 3 to 4 years, suggesting that patients who are alive at the 3-year landmark (especially in cases in which treatment had been stopped) will likely experience prolonged cancer remission. Quality-of-life and mixture-cure modeling data, as well as metrics such as treatment-free survival, are helping to define the value of this long-term survival. In this review, we describe the current treatment landscape for melanoma and discuss the long-term survival data with immunotherapies and targeted therapies, discussing how to best evaluate the value of long-term survival. We propose that some patients might be considered functionally cured if they have responded to treatment and remained treatment-free for at least 2 years without disease progression. Finally, we consider that, while there have been major advances in the treatment of melanoma in the past decade, there remains a need to improve outcomes for the patients with melanoma who do not experience durable survival.

The MAP kinase signal transduction pathway: promising therapeutic targets used in the treatment of melanoma

INTRODUCTION

Mitogen-activated protein kinase (MAPK) signal transduction pathway inhibition through the use of agents binding to signal cascade kinases BRAF and MEK has become a key treatment strategy of patients with BRAF-mutant, unresectable melanoma.

AREAS COVERED

Detailed analysis is undertaken of the current data, presenting the efficacy and safety of recently developed therapies targeting BRAF and MEK inhibition in the setting of unresectable melanoma. MAPK signal transduction, translational findings, current phase I, II and III clinical trials, and ongoing studies are explored, including use of MAPK pathway inhibition in the neoadjuvant and adjuvant settings as well as in combination with immunotherapy and other therapies.

EXPERT OPINION

Inhibition of the MAPK pathway significantly improves response, progression-free survival, disease specific survival, and overall survival for patients with BRAF-mutant, unresectable melanoma. The concurrent administration of BRAF and MEK inhibiting agents improves response rate and outcomes and reduces serious adverse effects, including development of new cutaneous malignancies. Triplet therapy with BRAK/MEK combination and immunotherapy has shown in early results to increase duration of response and may be best used sequentially as opposed to concurrently to avoid treatment limiting toxicities. Current clinical trials will further define these therapies and their impact on treatment of melanoma.

Preclinical discovery and clinical development of encorafenib for the treatment of melanoma

INTRODUCTION

Nearly 50% of patients with metastatic melanoma harbor a BRAFV600-mutation, which can be targeted with the use of BRAF and MEK inhibitors, either in the front-line or treatment-refractory setting. Encorafenib is the newest BRAF-inhibitor to have received FDA-approval in combination with the MEK inhibitor binimetinib.

AREAS COVERED

The authors provide an overview of the preclinical development and the clinical trials that led to the use of encorafenib in BRAFV600-mutant melanoma. They also give discussion on its current use in clinical practice, providing their expert perspectives on the subject.

EXPERT OPINION

Preclinical research has provided strong rationale for upgrading encorafenib investigation into clinical development/testing. However, there is not yet enough data to determine where encorafenib may fit in comparison to other drugs in the same class, and ongoing trials will further define its role in the treatment of melanoma. Of note, there are ongoing studies that further explore the role of encorafenib + binimetinib such as in combination regimens with immunotherapy drugs, and in brain metastases.

Efficacy of immune checkpoint inhibitors in different types of melanoma

Immunotherapy can be used for cutaneous, mucosal, uveal and conjunctival melanoma. Nevertheless, we cannot expect the same benefit from checkpoint inhibitors for all the types of melanoma. The different biological features can explain the variable efficacy. The main results obtained with immune checkpoint inhibitors in the various types of melanoma were reviewed.

Clinical and Recent Patents Applications of PD-1/PD-L1 Targeting Immunotherapy in Cancer Treatment-Current Progress, Strategy, and Future Perspective

Targeting PD-L1 and PD-1 interactions is a relatively new therapeutic strategy used to treat cancer. Inhibitors of PD-1/PD-L1 include peptides, small molecule chemical compounds, and antibodies. Several approved antibodies targeting PD-1 or PD-L1 have been patented with good curative effect in various cancer types in clinical practices. While the current antibody therapy is facing development bottleneck, some companies have tried to develop PD-L1 companion tests to select patients with better diagnosis potential. Meanwhile, many companies have recently synthesized small molecule inhibitors of PD-1/PD-L1 interactions and focused on searching for novel biomarker to predict the efficacy of anti-PD-1/PD-L1 drugs. This review summarized clinical studies and patent applications related to PD-1/PD-L1 targeted therapy and also discussed progress in inhibitors of PD-1/PD-L1.

Targeted Therapy in Melanoma and Mechanisms of Resistance

The common mutation BRAFV600 in primary melanomas activates the mitogen-activated protein kinase/extracellular-signal-regulated kinase (MAPK/ERK) pathway and the introduction of proto-oncogene B-Raf (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors (BRAFi and MEKi) was a breakthrough in the treatment of these cancers. However, 15–20% of tumors harbor primary resistance to this therapy, and moreover, patients develop acquired resistance to treatment. Understanding the molecular phenomena behind resistance to BRAFi/MEKis is indispensable in order to develop novel targeted therapies. Most often, resistance develops due to either the reactivation of the MAPK/ERK pathway or the activation of alternative kinase signaling pathways including phosphatase and tensin homolog (PTEN), neurofibromin 1 (NF-1) or RAS signaling. The hyperactivation of tyrosine kinase receptors, such as the receptor of the platelet-derived growth factor β (PDFRβ), insulin-like growth factor 1 receptor (IGF-1R) and the receptor for hepatocyte growth factor (HGF), lead to the induction of the AKT/3-phosphoinositol kinase (PI3K) pathway. Another pathway resulting in BRAFi/MEKi resistance is the hyperactivation of epidermal growth factor receptor (EGFR) signaling or the deregulation of microphthalmia-associated transcription factor (MITF).

Combined Therapy with Anti-PD1 and BRAF and/or MEK Inhibitor for Advanced Melanoma: A Multicenter Cohort Study

Despite significant progress in melanoma survival, therapeutic options are still needed in case of progression under immune checkpoint inhibitors (ICI), and resistance to targeted therapies (TT) in BRAF-mutated melanomas. This study aimed to assess the safety of combined ICI and TT as a rescue line in real-life clinical practice. We conducted a study within the prospective French multicentric MelBase cohort, including patients treated with a combination of anti-PD1 (pembrolizumab/nivolumab) and BRAF inhibitor (BRAFi: dabrafenib/vemurafenib) and/or MEK inhibitors (MEKi: trametinib/cobimetinib) for BRAF mutated or wild-type advanced melanoma. Fifty-nine patients were included: 30% received the triple combination, 34% an anti-PD1 and BRAFi, and 36% an anti-PD1 and MEKi. Grade 3-4 adverse events occurred in 12% of patients. Permanent discontinuation or dose reduction of one of the treatments for toxicity was reported in 14% and 7% of patients, respectively. In the BRAF wild-type subgroup, treatment with MEKi and anti-PD1 induced a tumor control rate of 83% and median progression-free survival of 7.1 months. The combination of anti-PD1 and BRAFi and/or MEKi was a safe rescue line for advanced melanoma patients previously treated with ICI/TT. The benefit of these combinations, specifically anti-PD1 and MEKi in BRAF wild-type melanoma patients, needs to be prospectively studied.

Atezolizumab, vemurafenib, and cobimetinib as first-line treatment for unresectable advanced BRAFV600 mutation-positive melanoma (IMspire150): primary analysis of the randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

IMspire150 aimed to evaluate first-line combination treatment with BRAF plus MEK inhibitors and immune checkpoint therapy in BRAF^V600 mutation-positive advanced or metastatic melanoma.

METHODS

IMspire150 was a randomised, double-blind, placebo-controlled phase 3 study done at 112 institutes in 20 countries. Patients with unresectable stage IIIc-IV, BRAF^V600 mutation-positive melanoma were randomly assigned 1:1 to 28-day cycles of atezolizumab, vemurafenib, and cobimetinib (atezolizumab group) or atezolizumab placebo, vemurafenib, and cobimetinib (control group). In cycle 1, all patients received vemurafenib and cobimetinib only; atezolizumab placebo was added from cycle 2 onward. Randomisation was stratified by lactate dehydrogenase concentration and geographical region. Blinding for atezolizumab was achieved by means of an identical intravenous placebo, and blinding for vemurafenib was achieved by means of a placebo tablet. The primary outcome was investigator-assessed progression-free survival. This trial (ClinicalTrials.gov, NCT02908672) is ongoing but no longer recruiting patients.

FINDINGS

Between Jan 13, 2017, and April 26, 2018, 777 patients were screened and 514 were enrolled and randomly assigned to the atezolizumab group (n=256) or control group (n=258). At a median follow-up of 18·9 months (IQR 10·4-23·8), progression-free survival as assessed by the study investigator was significantly prolonged with atezolizumab versus control (15·1 vs 10·6 months; hazard ratio [HR] 0·78; 95% CI 0·63-0·97; p=0·025). Common treatment-related adverse events (>30%) in the atezolizumab and control groups were blood creatinine phosphokinase increased (51·3% vs 44·8%), diarrhoea (42·2% vs 46·6%), rash (40·9%, both groups), arthralgia (39·1% vs 28·1%), pyrexia (38·7% vs 26·0%), alanine aminotransferase increased (33·9% vs 22·8%), and lipase increased (32·2% vs 27·4%); 13% of patients in the atezolizumab group and 16% in the control group stopped all treatment because of adverse events.

INTERPRETATION

The addition of atezolizumab to targeted therapy with vemurafenib and cobimetinib was safe and tolerable and significantly increased progression-free survival in patients with BRAF^V600 mutation-positive advanced melanoma.

FUNDING

F Hoffmann-La Roche and Genentech.

The future of cancer immunotherapy: microenvironment-targeting combinations

Immunotherapy holds the potential to induce durable responses, but only a minority of patients currently respond. The etiologies of primary and secondary resistance to immunotherapy are multifaceted, deriving not only from tumor intrinsic factors, but also from the complex interplay between cancer and its microenvironment. In addressing frontiers in clinical immunotherapy, we describe two categories of approaches to the design of novel drugs and combination therapies: the first involves direct modification of the tumor, while the second indirectly enhances immunogenicity through alteration of the microenvironment. By systematically addressing the factors that mediate resistance, we are able to identify mechanistically-driven novel approaches to improve immunotherapy outcomes.

Modern Aspects of Immunotherapy with Checkpoint Inhibitors in Melanoma

Although melanoma is one of the most immunogenic tumors, it has an ability to evade anti-tumor immune responses by exploiting tolerance mechanisms, including negative immune checkpoint molecules. The most extensively studied checkpoints represent cytotoxic T lymphocyte-associated protein-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Immune checkpoint inhibitors (ICI), which were broadly applied for melanoma treatment in the past decade, can unleash anti-tumor immune responses and result in melanoma regression. Patients responding to the ICI treatment showed long-lasting remission or disease control status. However, a large group of patients failed to respond to this therapy, indicating the development of resistance mechanisms. Among them are intrinsic tumor properties, the dysfunction of effector cells, and the generation of immunosuppressive tumor microenvironment (TME). This review discusses achievements of ICI treatment in melanoma, reasons for its failure, and promising approaches for overcoming the resistance. These methods include combinations of different ICI with each other, strategies for neutralizing the immunosuppressive TME and combining ICI with other anti-cancer therapies such as radiation, oncolytic viral, or targeted therapy. New therapeutic approaches targeting other immune checkpoint molecules are also discussed.

Nanosystems for Improved Targeted Therapies in Melanoma

Melanoma is one of the most aggressive forms of skin cancer, with limited therapeutic options. Since its incidence has been rapidly rising in recent years, the study of new targeted therapeutic strategies has increased. The implication of nanoscience in the development of alternative targeted therapies for melanoma has multiple benefits and could significantly improve the outcome of melanoma patients. In this paper, we review the most recent progress in the field of targeted therapies, emphasizing the impact of nanoscale materials on the targeting and controlled release of anti-tumor drugs. The applications of nanomedicine in the management of melanoma are extensive and refer to sentinel lymph node mapping, chemotherapy, and RNA interference; each of these applications harboring the potential to develop efficient and personalized diagnostic techniques and therapies. Further research, especially in clinical trials, is needed to establish whether fighting melanoma on the nanoscale level represents the key to reaching a critical inflection point in mankind’s battle with metastatic melanoma.

Anti-PD-1 and Novel Combinations in the Treatment of Melanoma-An Update

Until recently, distant metastatic melanoma was considered refractory to systemic therapy. A better understanding of the interactions between tumors and the immune system and the mechanisms of regulation of T-cells led to the development of immune checkpoint inhibitors. This review summarizes the current novel data on the treatment of metastatic melanoma with anti-programmed cell death protein 1 (PD-1) antibodies and anti-PD-1-based combination regimens, including clinical trials presented at major conference meetings. Immune checkpoint inhibitors, in particular anti-PD-1 antibodies such as pembrolizumab and nivolumab and the combination of nivolumab with the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody ipilimumab can achieve long-term survival for patients with metastatic melanoma. The anti-PD-1 antibodies nivolumab and pembrolizumab were also approved for adjuvant treatment of patients with resected metastatic melanoma. Anti-PD-1 antibodies appear to be well tolerated, and toxicity is manageable. Nivolumab combined with ipilimumab achieves a 5 year survival rate of more than 50% but at a cost of high toxicity. Ongoing clinical trials investigate novel immunotherapy combinations and strategies (e.g., Talimogene laherparepvec (T-VEC), Bempegaldesleukin (BEMPEG), incorporation or sequencing of targeted therapy, incorporation or sequencing of radiotherapy), and focus on poor prognosis groups (e.g., high tumor burden/LDH levels, anti-PD-1 refractory melanoma, and brain metastases).