Post-Transplant Nivolumab Plus Unselected Autologous Lymphocytes in Refractory Hodgkin Lymphoma: A Feasible and Promising Salvage Therapy Associated With Expansion and Maturation of NK Cells

Immune checkpoint inhibitors (CI) have demonstrated clinical activity in Hodgkin Lymphoma (HL) patients relapsing after autologous stem cell transplantation (ASCT), although only 20% complete response (CR) rate was observed. The efficacy of CI is strictly related to the host immune competence, which is impaired in heavily pre-treated HL patients. Here, we aimed to enhance the activity of early post-ASCT CI (nivolumab) administration with the infusion of autologous lymphocytes (ALI). Twelve patients with relapse/refractory (R/R) HL (median age 28.5 years; range 18-65), underwent lymphocyte apheresis after first line chemotherapy and then proceeded to salvage therapy. Subsequently, 9 patients with progressive disease at ASCT received early post-transplant CI supported with four ALI, whereas 3 responding patients received ALI alone, as a control cohort. No severe adverse events were recorded. HL-treated patients achieved negative PET scan CR and 8 are alive and disease-free after a median follow-up of 28 months. Four patients underwent subsequent allogeneic SCT. Phenotypic analysis of circulating cells showed a faster expansion of highly differentiated NK cells in ALI plus nivolumab-treated patients as compared to control patients. Our data show anti-tumor activity with good tolerability of ALI + CI for R/R HL and suggest that this setting may accelerate NK cell development/maturation and favor the expansion of the “adaptive” NK cell compartment in patients with HCMV seropositivity, in the absence of HCMV reactivation.

Advances in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent disease with a progression that is modulated by the immune system. Systemic therapy is used in the advanced stage and until 2017 consisted only of antiangiogenic tyrosine kinase inhibitors (TKIs). Immunotherapy with checkpoint inhibitors has shown strong anti-tumour activity in a subset of patients and the combination of the anti-PDL1 antibody atezolizumab and the VEGF-neutralizing antibody bevacizumab has or will soon become the standard of care as a first-line therapy for HCC, whereas the anti-PD1 agents nivolumab and pembrolizumab are used after TKIs in several regions. Other immune strategies such as adoptive T-cell transfer, vaccination or virotherapy have not yet demonstrated consistent clinical activity. Major unmet challenges in HCC checkpoint immunotherapy are the discovery and validation of predictive biomarkers, advancing treatment to earlier stages of the disease, applying the treatment to patients with liver dysfunction and the discovery of more effective combinatorial or sequential approaches. Combinations with other systemic or local treatments are perceived as the most promising opportunities in HCC and some are already under evaluation in large-scale clinical trials. This Review provides up-to-date information on the best use of currently available immunotherapies in HCC and the therapeutic strategies under development.

Advances in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent disease with a progression that is modulated by the immune system. Systemic therapy is used in the advanced stage and until 2017 consisted only of antiangiogenic tyrosine kinase inhibitors (TKIs). Immunotherapy with checkpoint inhibitors has shown strong anti-tumour activity in a subset of patients and the combination of the anti-PDL1 antibody atezolizumab and the VEGF-neutralizing antibody bevacizumab has or will soon become the standard of care as a first-line therapy for HCC, whereas the anti-PD1 agents nivolumab and pembrolizumab are used after TKIs in several regions. Other immune strategies such as adoptive T-cell transfer, vaccination or virotherapy have not yet demonstrated consistent clinical activity. Major unmet challenges in HCC checkpoint immunotherapy are the discovery and validation of predictive biomarkers, advancing treatment to earlier stages of the disease, applying the treatment to patients with liver dysfunction and the discovery of more effective combinatorial or sequential approaches. Combinations with other systemic or local treatments are perceived as the most promising opportunities in HCC and some are already under evaluation in large-scale clinical trials. This Review provides up-to-date information on the best use of currently available immunotherapies in HCC and the therapeutic strategies under development.

Treg-mediated acquired resistance to immune checkpoint inhibitors

T Regulatory cells (Tregs) act as a double-edged sword by regulating immune homeostasis (protective role) and inhibiting immune responses in different disease settings (pathological role). They contribute to cancer development and progression by suppressing T effector cell (Teff) functions. Decreased ratios of intratumoral CD8⁺ T cells to Tregs have been associated with poor prognosis in most cancer types. Targeting immune checkpoints (ICs), such as cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death-1 (PD-1), by immune checkpoint inhibitors (ICIs) in cancer patients has been beneficial in inducing anti-tumor immune responses and improving clinical outcomes. However, response rates remain relatively low, ranging from 15 to 40% depending on cancer type. Additionally, a significant proportion of patients who initially demonstrates a clinical response can acquire resistance overtime. This acquired resistance could occur due to the emergence of compensatory mechanisms within the tumor microenvironment (TME) to evade the anti-tumor effects of ICIs. In this review, we describe the immunosuppressive role of Tregs in the TME, the effects of currently approved ICIs on Treg phenotype and function, and the mechanisms of acquired resistance to ICIs mediated by Tregs within the TME, such as the over-expression of ICs, the up-regulation of immunosuppressive molecules, and apoptotic Treg-induced immunosuppression. We also describe potential therapeutic strategies to target Tregs in combination with ICIs aiming to overcome such resistance and improve clinical outcomes. Elucidating the Treg-mediated acquired resistance mechanisms should benefit the designing of well-targeted therapeutic strategies to overcome resistance and maximize the therapeutic efficacy in cancer patients.

The use of cytological material in melanoma for programmed death ligand 1 immunostaining

OBJECTIVE

Interest in immune therapies has exploded since the 2014 approval of first-generation programmed cell death 1 blocking antibodies for use in advanced melanoma. Clinical trials have focused primarily on histological material as the gold standard for evaluating programmed death ligand 1 (PD-L1) by immunoperoxidase (IPOX) studies. Studies validating the use of cytological specimens in the assessment of PD-L1 by IPOX staining are needed to optimise tissue utilisation in complementary diagnostic testing.

METHODS

Twenty-three melanoma surgical biopsies (SBx) with an IPOX stain for PD-L1 clone 28-8, and a corresponding cytological specimen from the same patient, adequate for PD-L1 evaluation, were selected. Cell-transfer cell blocks (CBs) and conventional CBs were used to perform PD-L1 testing. Tumour proportion scores (TPS) were generated and the results were correlated with the corresponding SBx.

RESULTS

Overall agreement (OA) using a ≥1% TPS cut-off for SBx compared to CB was 88.9%, positive percent agreement (PPA) was 87.5%, and negative percent agreement (NPA) was 100%, OA using a ≥5% TPS cut-off was 55.6%, PPA was 42.9%, and NPA was 100%. SBx compared to cell-transfer CB using a ≥1% TPS cut-off had an OA of 65.2%, a PPA of 55.6%, and a NPA of 100%, while a ≥5% TPS cut-off generated an OA of 52.2%, a PPA of 35.7%, and a NPA of 77.8%.

CONCLUSION

Our results demonstrate that cytological material, particularly conventional CB, is a viable alternative for evaluating PD-L1 in melanoma cases and suggest that a lower threshold (≥1%) may be beneficial when evaluating cytological material.

Immune Correlates of GM-CSF and Melanoma Peptide Vaccination in a Randomized Trial for the Adjuvant Therapy of Resected High-Risk Melanoma (E4697)

Purpose: E4697 was a multicenter intergroup randomized placebo-controlled phase III trial of adjuvant GM-CSF and/or a multiepitope melanoma peptide vaccine for patients with completely resected, high-risk stage III/IV melanoma.Experimental Design: A total of 815 patients were enrolled from December 1999 to October 2006 into this six-arm study. GM-CSF was chosen to promote the numbers and functions of dendritic cells (DC). The melanoma antigen peptide vaccine (Tyrosinase_{368-376 (370D)}, gp100_{209-217 (210M)}, MART-1_27-35) in montanide was designed to promote melanoma-specific CD8⁺ T-cell responses.Results: Although the overall RFS and OS were not significantly improved with the vaccine or GM-CSF when compared with placebo, immunomodulatory effects were observed in peripheral blood and served as important correlates to this therapeutic study. Peripheral blood was examined to evaluate the impact of GM-CSF and/or the peptide vaccine on peripheral blood immunity and to investigate potential predictive or prognostic biomarkers. A total of 11.3% of unvaccinated patients and 27.1% of vaccinated patients developed peptide-specific CD8⁺ T-cell responses. HLA-A2⁺ patients who had any peptide-specific CD8⁺ T-cell response at day +43 tended to have poorer OS in univariate analysis. Patients receiving GM-CSF had significant reduction in percentages of circulating myeloid dendritic cells (mDC) and plasmacytoid DC (pDC) at day +43. In a subset of patients who received GM-CSF, circulating myeloid-derived suppressor cells (MDSC), and anti-GM-CSF-neutralizing antibodies (Nabs) were also modulated. The majority of patients developed anti-GM-CSF Nabs, which correlated with improved RFS and OS.Conclusions: The assessment of cellular and humoral responses identified counterintuitive immune system changes correlating with clinical outcome. Clin Cancer Res; 23(17); 5034-43. ©2017 AACR.

Emerging biomarkers for PD-1 pathway cancer therapy

The field of immuno-oncology has witnessed unprecedented success in recent years, with several PD=1 and PD-L1 inhibitors obtaining US FDA registration and breakthrough drug therapy designation in multiple tumor types. Despite its clear efficacy in certain cancers, treatment with these agents carries a risk of immune-related toxicities and substantial financial burden. It is, therefore, critical to identify patients likely to benefit from such immunotherapies and develop strategies to differentiate responders from nonresponders early during treatment. Here we discuss the development of predictive and treatment response biomarkers for immune checkpoint inhibitors. We first examine the role of PD-L1 expression, the most extensively studied predictive biomarker of response, and further discuss emerging putative predictive biomarkers. We also detail challenges faced in the development of response assessments for immunotherapeutics and propose other biomarkers that may be useful as surrogate intermediate end points of response.

The Where, the When, and the How of Immune Monitoring for Cancer Immunotherapies in the Era of Checkpoint Inhibition

Clinical trials with immune checkpoint inhibitors have provided important insights into the mode of action of anticancer immune therapies and potential mechanisms of immune escape. Development of the next wave of rational clinical combination strategies will require a deep understanding of the mechanisms by which combination partners influence the battle between the immune system's capabilities to fight cancer and the immune-suppressive processes that promote tumor growth. This review focuses on our current understanding of tumor and circulating pharmacodynamic correlates of immune modulation and elaborates on lessons learned from human translational research with checkpoint inhibitors. Actionable tumor markers of immune activation including CD8(+)T cells, PD-L1 IHC as a pharmacodynamic marker of T-cell function, T-cell clonality, and challenges with conduct of trials that ask scientific questions from serial biopsies are addressed. Proposals for clinical trial design, as well as future applications of peripheral pharmacodynamic endpoints as potential surrogates of early clinical activity, are discussed. On the basis of emerging mechanisms of response and immune escape, we propose the concept of the tumor immunity continuum as a framework for developing rational combination strategies.

Immunomodulation: checkpoint blockade etc

The immune microenvironment is considered a major obstacle to generating an effective antitumor immune response. Checkpoint inhibitors manipulate the co-stimulatory response between antigen-presenting cells and immune cells-or between the tumor and immune cells-to elicit an antitumor immune response that would have otherwise been suppressed. Checkpoint inhibitors have shown great promise in the clinics, and some inhibitors such as anti-CTLA-4 antibodies and anti-PD-1 antibodies have gained FDA approval for certain tumors. Here we will discuss the current state of checkpoint inhibitors, biomarker strategies, and management of associated toxicities in glioblastoma.

Baseline Biomarkers for Outcome of Melanoma Patients Treated with Pembrolizumab

PURPOSE

Biomarkers for outcome after immune-checkpoint blockade are strongly needed as these may influence individual treatment selection or sequence. We aimed to identify baseline factors associated with overall survival (OS) after pembrolizumab treatment in melanoma patients.

EXPERIMENTAL DESIGN

Serum lactate dehydrogenase (LDH), routine blood count parameters, and clinical characteristics were investigated in 616 patients. Endpoints were OS and best overall response following pembrolizumab treatment. Kaplan-Meier analysis and Cox regression were applied for survival analysis.

RESULTS

Relative eosinophil count (REC) ≥1.5%, relative lymphocyte count (RLC) ≥17.5%, ≤2.5-fold elevation of LDH, and the absence of metastasis other than soft-tissue/lung were associated with favorable OS in the discovery (n = 177) and the confirmation (n = 182) cohort and had independent positive impact (all P < 0.001). Their independent role was subsequently confirmed in the validation cohort (n = 257; all P < 0.01). The number of favorable factors was strongly associated with prognosis. One-year OS probabilities of 83.9% versus 14.7% and response rates of 58.3% versus 3.3% were observed in patients with four of four compared to those with none of four favorable baseline factors present, respectively.

CONCLUSIONS

High REC and RLC, low LDH, and absence of metastasis other than soft-tissue/lung are independent baseline characteristics associated with favorable OS of patients with melanoma treated with pembrolizumab. Presence of four favorable factors in combination identifies a subgroup with excellent prognosis. In contrast, patients with no favorable factors present have a poor prognosis, despite pembrolizumab, and additional treatment advances are still needed. A potential predictive impact needs to be further investigated. Clin Cancer Res; 22(22); 5487-96. ©2016 AACR.

Tumor-targeted and immune-targeted monoclonal antibodies: Going from passive to active immunotherapy

Monoclonal antibodies (mAbs) have inaugurated the concepts of tumor-targeted therapy and personalized medicine. A new family of mAbs is currently emerging in the clinic, which target immune cells rather than cancer cells. These immune-targeted therapies have recently demonstrated long-term tumor responses in adults with refractory/relapsing metastatic solid tumors. Pediatric cancers are different from their adult counterparts in terms of histological features and immune infiltrates. However, the same immune checkpoint targets can be expressed within the microenvironment of pediatric tumors. The benefits of immune checkpoint blockade in pediatric cancers are currently under evaluation in early phase clinical trials.

Immune checkpoint combinations from mouse to man

The discovery that antibody blockade of the T cell co-inhibitory receptor cytotoxic T lymphocyte-associated protein 4 (CTLA-4) can restore tumor immunity against many murine transplantable tumors leading to complete rejection of established cancer forever changed the field of immunotherapy. In more robust murine models as well as human cancer, however, CTLA-4 blockade alone can slow tumor growth and extend patient survival, but is rarely curative. Subsequent studies have revealed a large family of T cell immune checkpoint receptors which tumors engage to shield themselves from host immunity. As with CTLA-4, blockade of one of these additional inhibitory receptors, programmed death 1, has led to remarkable therapeutic responses against tumors of multiple lineages. Checkpoint monotherapy has demonstrated that durable, immune-mediated cures of established metastatic cancers are possible, yet the percentage of patients experiencing these outcomes remains low due to both redundant mechanisms of immune suppression in the tumor and limiting toxicity associated with some therapies. Thus, extending the curative potential of immunotherapy to a larger percentage of patients with a broader spectrum of malignancies will likely require combinations of co-inhibitory blockade and co-stimulatory activation designed to peel back multiple layers of tumor immune suppression while at the same time minimizing immune-mediated toxicity. As over a dozen T cell immune checkpoints and an additional dozen more co-stimulatory receptors have now been described, the challenge before us is to identify the most advantageous combinations of these agents based on the knowledge of their underlying biology and preclinical studies in murine tumor models.

Current status and future directions of the immune checkpoint inhibitors ipilimumab, pembrolizumab, and nivolumab in oncology

OBJECTIVE

To provide the clinician with an update and the current status and future direction of approved immune checkpoint inhibitors (ICIs) in oncology.

DATA SOURCES

A PubMed search from January 1, 1966 to March 13, 2015 was performed using the key terms ipilimumab, pembrolizumab, lambrolizumab, nivolumab, immune checkpoint inhibitor, MDX-010, MDX-101, BMS-734016, MK-3475, SCH 900475, MDX-1106, BMS-936558, ONO-4538, CTLA-4, PD-1, or PD-L1 and cancer, oncology, or neoplasm. Additional references were identified from the investigators(') personal files, recent oncology meetings, review articles, clinical guidelines, and package inserts.

STUDY SELECTION AND DATA EXTRACTION

All English-language clinical trials assessing the safety and efficacy of ipilimumab, nivolumab, and pembrolizumab in cancer were considered. The PubMed search resulted in 215 trials; 33 met inclusion criteria. A further 28 trials were identified from the above sources; 61 trials from 2005 to 2015 were included. We consolidated and clarified treatment recommendations for the management of immune-related adverse events (irAEs), assessed response criteria, and calculated the clinical utility of leading tumor profiling options.

DATA SYNTHESIS

Ipilimumab and nivolumab, but not pembrolizumab, have an overall survival (OS) advantage over chemotherapy first line in unresectable/metastatic melanoma. Nivolumab has an OS advantage versus chemotherapy in second-line squamous non-small-cell lung cancer. Data in other settings are promising. Nivolumab and pembrolizumab are better tolerated than ipilimumab. Further validation of response criteria is needed. Tumor profiling to predict clinical benefit is premature but promising.

CONCLUSIONS

The treatment landscape in oncology is quickly evolving with the advent of ICIs.

The Next Immune-Checkpoint Inhibitors: PD-1/PD-L1 Blockade in Melanoma

PURPOSE

Blocking the interaction between the programmed cell death (PD)-1 protein and one of its ligands, PD-L1, has been reported to have impressive antitumor responses. Therapeutics targeting this pathway are currently in clinical trials. Pembrolizumab and nivolumab are the first of this anti-PD-1 pathway family of checkpoint inhibitors to gain accelerated approval from the US Food and Drug Administration (FDA) for the treatment of ipilimumab-refractory melanoma. Nivolumab has been associated with improved overall survival compared with dacarbazine in patients with previously untreated wild-type serine/threonine-protein kinase B-raf proto-oncogene BRAF melanoma. Although the most mature data are in the treatment of melanoma, the FDA has granted approval of nivolumab for squamous cell lung cancer and the breakthrough therapy designation to immune- checkpoint inhibitors for use in other cancers: nivolumab, an anti-PD-1 monoclonal antibody, for Hodgkin lymphoma, and MPDL-3280A, an anti-PD-L1 monoclonal antibody, for bladder cancer and non-small cell lung cancer. Here we review the literature on PD-1 and PD-L1 blockade and focus on the reported clinical studies that have included patients with melanoma.

METHODS

PubMed was searched to identify relevant clinical studies of PD-1/PD-L1-targeted therapies in melanoma. A review of data from the current trials on clinicaltrial.gov was incorporated, as well as data presented in abstracts at the 2014 annual meeting of the American Society of Clinical Oncology, given the limited number of published clinical trials on this topic.

FINDINGS

The anti-PD-1 and anti-PD-L1 agents have been reported to have impressive antitumor effects in several malignancies, including melanoma. The greatest clinical activity in unselected patients has been seen in melanoma. Tumor expression of PD-L1 is a suggestive, but inadequate, biomarker predictive of response to immune-checkpoint blockade. However, tumors expressing little or no PD-L1 are less likely to respond to PD-1 pathway blockade. Combination checkpoint blockade with PD-1 plus cytotoxic T-lymphocyte antigen (CTLA)-4 blockade appears to improve response rates in patients who are less likely to respond to single-checkpoint blockade. Toxicity with PD-1 blocking agents is less than the toxicity with previous immunotherapies (eg, interleukin 2, CTLA-4 blockade). Certain adverse events can be severe and potentially life threatening, but most can be prevented or reversed with close monitoring and appropriate management.

IMPLICATIONS

This family of immune-checkpoint inhibitors benefits not only patients with metastatic melanoma but also those with historically less responsive tumor types. Although a subset of patients responds to single-agent blockade, the initial trial of checkpoint-inhibitor combinations has reported a potential to improve response rates. Combination therapies appear to be a means of increasing response rates, albeit with increased immune-related adverse events. As these treatments become available to patients, education regarding the recognition and management of immune-related effects of immune-checkpoint blockade will be essential for maximizing clinical benefit.

Anti-PD1 and anti-PD-L1 in the treatment of metastatic melanoma

Programmed cell death receptor-1 (PD-1) and programmed cell death-1 ligand-1 (PD-L1) represent promising novel targets in immunotherapy. PD-1 is an inhibitory receptor involved in T-cell regulation that is expressed by activated T cells. Nivolumab and pembrolizumab are anti-PD-1 antibodies that have shown antitumor activity and acceptable tolerability in patients with metastatic melanoma in preclinical development and Phase I/II clinical trials. Several ongoing Phase III studies are further investigating the efficacy and safety of anti-PD-1 therapy in melanoma. Initial data on the combination of anti-PD-1 and anti-cytotoxic T-lymphocyte-associated antigen 4 blockade with nivolumab and ipilimumab also appear promising. Monoclonal antibodies to blockade PD-L1 may also be an effective immunotherapy strategy in melanoma and several anti-PD-L1 antibodies are in development.

CTLA-4 and PD-1 Pathway Blockade: Combinations in the Clinic

Checkpoint blocking antibodies targeting regulatory molecules on T cells such as CTLA-4 and PD-1 have reinvigorated the field of cancer immunotherapy. These agents have demonstrated clinical activity across a variety of tumor types. Now that safety and clinical activity has been demonstrated in the monotherapy setting, the field is moving in the direction of testing novel combinations.

[Breaking immune tolerance in cancer]

The discovery and understanding of complex cellular interactions that govern the immune system contributed to the pharmacological targeting of anti-tumor immunity. The activity of immune effector cells, such as NK and T-cells, is regulated by a wide range of activating and inhibiting receptors or ligands. Drugs that target these receptors or ligands can modulate the immune response by exerting antagonistic or agonistic effects. Over the past decade, several immunomodulators have demonstrated clinical effectiveness, and three of them have already been approved for use in oncology. The development of these immunotherapy approaches presented unique challenges for safety and efficacy, requiring revising clinical response criteria and the establishment of guidelines to help oncologists to manage properly inflammatory toxicities. The introduction of these immunotherapies is a revolution in oncology. However, additional efforts in terms of optimizing treatment administration and identification of biomarkers are needed. Identifying the immunodynamics of various immunomodulators should allow a better understanding of anti-tumor and inflammatory mechanisms, and certainly give the opportunity to develop effective therapeutic combinations without potentiating adverse events.

Immune modulation for cancer therapy

BACKGROUND

Immune modulation in cancer refers to a range of treatments aimed at harnessing a patient's immune system to achieve tumour control, stabilisation, and potential eradication of disease. A novel therapeutic drug class called immune checkpoint-blocking antibodies modulate T-cell pathways that regulate T cells and have the potential to reinvigorate an antitumour immune response. Ipilimumab was the first FDA-approved immune checkpoint antibody licensed for the treatment of metastatic melanoma (MM) and blocks a checkpoint molecule called cytotoxic T-lymphocyte antigen 4 (CTLA-4).

METHODS

Herein we review the preclinical and clinical development of ipilimumab. We outline the mode of action of these agents and other immune checkpoint inhibitors, the management of their toxicities, and how to adequately assess response to treatment.

RESULTS

As a result of these data, a number of other antibodies that block novel checkpoint molecules including programmed death-1 (PD-1), and corresponding ligands such as programmed death ligand-1 (PD-L1) are under preclinical and clinical development, and have demonstrated activity in multiple tumour types.

CONCLUSIONS

This review will summarise the mechanism of action and clinical development of immune checkpoint antibodies, as well as lessons learned in the management and assessment of patients receiving these agents.

Immune modulation in cancer with antibodies

Ipilimumab is the prototypical immunomodulatory antibody, approved by the FDA in 2011 for advanced melanoma on the basis of survival benefit. Since that time, we have made significant strides in optimizing this therapy: we have characterized the spectrum of immune-related adverse events and learned how to mitigate them with treatment algorithms, discovered potential biomarkers of activity, and identified the potential synergy between checkpoint modulation and other therapeutic modalities. Recent phase I trials have established the efficacy and safety of next-generation checkpoint agents, including PD-1 and PD-L1 inhibitors, across multiple tumor types. Much work lies ahead in developing these next-generation checkpoint agents, testing them in combination, and determining how to integrate them into the treatment paradigms of various tumor types.

Recent advances in melanoma systemic therapy. BRAF inhibitors, CTLA4 antibodies and beyond

Metastatic melanoma has a poor prognosis and until recently systemic therapy was ineffective. Advances in the understanding of tumour biology and immune regulation have led to the development of targeted agents that have changed clinical practice, with further improvements expected with new compounds and combinations. The first major advance was the development of selective mitogen-activated protein (MAP) kinase inhibitors (BRAF and MEK inhibitors) and immune checkpoint blockade with a CTLA4 antibody (ipilimumab). These drugs proved vastly superior to conventional chemotherapy, however response, resistance and toxicity were limitations. The second major advance is the development of other immune checkpoint blocking agents, including PD-1 and PD-L1 antibodies, and the use of BRAF and MEK inhibitors in combination, with a higher proportion of durable responses coupled with less toxicity. In an effort to improve outcomes for patients with melanoma further, trials are underway examining the combination of MAPK inhibitors, immunotherapies and other pathway inhibitors and adjuvant studies of many of these agents have commenced.