Survival, durable tumor remission, and long-term safety in patients with advanced melanoma receiving nivolumab

Immune Effects of Chemotherapy, Radiation, and Targeted Therapy and Opportunities for Combination With Immunotherapy

There have been significant advances in cancer treatment over the past several years through the use of chemotherapy, radiation therapy, molecularly targeted therapy, and immunotherapy. Despite these advances, treatments such as monotherapy or monomodality have significant limitations. There is increasing interest in using these strategies in combination; however, it is not completely clear how best to incorporate molecularly targeted and immune-targeted therapies into combination regimens. This is particularly pertinent when considering combinations with immunotherapy, as other types of therapy may have significant impact on host immunity, the tumor microenvironment, or both. Thus, the influence of chemotherapy, radiation therapy, and molecularly targeted therapy on the host anti-tumor immune response and the host anti-host response (ie, autoimmune toxicity) must be taken into consideration when designing immunotherapy-based combination regimens. We present data related to many of these combination approaches in the context of investigations in patients with melanoma and discuss their potential relationship to management of patients with other tumor types. Importantly, we also highlight challenges of these approaches and emphasize the need for continued translational research.

Combinatorial immunotherapy with checkpoint blockers solves the problem of metastatic melanoma-An exclamation sign with a question mark

Results from recent clinical trials demonstrate that a combinatorial immunotherapeutic regimen based on 2 distinct checkpoint blockers, namely, the CTLA4-targeting agent ipilimumab and the PD-1-specific molecule nivolumab, causes objective responses in a majority of subjects with advanced melanoma. These findings revolutionize the treatment of a neoplasm that was considered incurable until recently. Nonetheless, announcing the defeat of melanoma appears premature. Indeed, a sizeable fraction of patients does not respond to ipilimumab plus nivolumab, and the long-term efficacy of this immunotherapeutic regimen has not yet been investigated. Moreover, many patients experience severe side effects, calling for the development of strategies that uncouple the efficacy of ipilimumab plus nivolumab from their toxicity.

Impaired T-Cell Function in B-Cell Lymphoma: A Direct Consequence of Events at the Immunological Synapse?

Tumors can escape immune destruction through the development of antigen loss variants and loss of antigen processing/presentation pathways, thereby rendering them invisible to T cells. Alternatively, mechanisms of peripheral T-cell tolerance that would normally be important for protection from the development of autoimmunity may also be co-opted to (i) generate an immuno-inhibitory tumor environment, (ii) promote development of regulatory cell populations, or (iii) cell-intrinsically inactivate tumor-specific T cells. Emerging evidence suggests that T-cell function is impaired in hematological malignancies, which may manifest from cognate interactions between T cells and the tumor. The immunological synapse forms the cognate T-cell and antigen-presenting cell interaction and is the site where key signalling events, including those delivered by co-inhibitory receptors, that determine the fate of T cells occur. Here, we review evidence that events at the immune synapse between T cells and malignant B cells and alterations in immune synapse function may contribute to loss of T-cell function in B-cell malignancies.

TGFβ Is a Master Regulator of Radiation Therapy-Induced Antitumor Immunity

T cells directed to endogenous tumor antigens are powerful mediators of tumor regression. Recent immunotherapy advances have identified effective interventions to unleash tumor-specific T-cell activity in patients who naturally develop them. Eliciting T-cell responses to a patient's individual tumor remains a major challenge. Radiation therapy can induce immune responses to model antigens expressed by tumors, but it remains unclear whether it can effectively prime T cells specific for endogenous antigens expressed by poorly immunogenic tumors. We hypothesized that TGFβ activity is a major obstacle hindering the ability of radiation to generate an in situ tumor vaccine. Here, we show that antibody-mediated TGFβ neutralization during radiation therapy effectively generates CD8(+) T-cell responses to multiple endogenous tumor antigens in poorly immunogenic mouse carcinomas. Generated T cells were effective at causing regression of irradiated tumors and nonirradiated lung metastases or synchronous tumors (abscopal effect). Gene signatures associated with IFNγ and immune-mediated rejection were detected in tumors treated with radiation therapy and TGFβ blockade in combination but not as single agents. Upregulation of programmed death (PD) ligand-1 and -2 in neoplastic and myeloid cells and PD-1 on intratumoral T cells limited tumor rejection, resulting in rapid recurrence. Addition of anti-PD-1 antibodies extended survival achieved with radiation and TGFβ blockade. Thus, TGFβ is a fundamental regulator of radiation therapy's ability to generate an in situ tumor vaccine. The combination of local radiation therapy with TGFβ neutralization offers a novel individualized strategy for vaccinating patients against their tumors.

Classifying Cancers Based on T-cell Infiltration and PD-L1

Cancer immunotherapy may become a major treatment backbone in many cancers over the next decade. There are numerous immune cell types found in cancers and many components of an immune reaction to cancer. Thus, the tumor has many strategies to evade an immune response. It has been proposed that four different types of tumor microenvironment exist based on the presence or absence of tumor-infiltrating lymphocytes and programmed death-ligand 1 (PD-L1) expression. We review this stratification and the latest in a series of results that shed light on new approaches for rationally designing ideal combination cancer therapies based on tumor immunology.

Liver resection and ablation for metastatic melanoma: A single center experience

BACKGROUND

The median survival for patients with stage IV metastatic melanoma is usually limited to approximately 1 year. In the case of liver metastasis, resection and ablation can achieve long-term survival. This study aimed to describe the outcomes after liver resection or ablation for metastatic melanoma to the liver and identify preoperative prognostic factors.

METHODS

Forty eight patients who underwent liver resection (n = 32) or percutaneous ablation (n = 16) were identified from the 1,523 patients with melanoma liver metastases evaluated between January1993 and January 2013.

RESULTS

Median OS was 25.9 months. Median OS was not different after ablation (18 months) and resection (26 months; P > 0.2). Patients in the ablation group more often presented with extrahepatic disease (EHD) (P = 0.008) and received more frequently systemic therapy before ablation (P = 0.005). Patients without EHD tended to have longer OS (26.5 vs. 12 months; P = 0.076) and PFS (13 vs. 5 months; P = 0.11) in the whole cohort. EHD was significantly associated with a worse OS in the resection group (P = 0.034).

CONCLUSION

Liver resection is associated to prolonged survival over 24 months and should be considered only in selected patients with metastatic disease confined to the liver. In patients not candidate for surgery, tumor ablation can be considered.

Enhancing the efficacy of adoptive cellular therapy by targeting tumor-induced immunosuppression

Strategies aimed at stimulating the immune system against cancer have signaled a new era for designing new effective therapies for patients. Recent breakthroughs in adoptive cellular therapy and in using checkpoint inhibitors for some patients have renewed much enthusiasm in this field. However, it has become apparent that tumors can use a multitude of inhibitory networks to effectively reduce antitumor immunity. This review discusses our current knowledge of these immune suppressive mechanisms used by tumors and describes potential new strategies that may counteract this problem resulting in significantly increasing therapeutic outcomes of adoptive immunotherapy in a higher proportion of patients.

Immuno-regulatory antibodies for the treatment of cancer

INTRODUCTION

After years of limited success, progress of anti-cancer immuno-therapeutics has been considerable over the past decade. Key to this progress has been the application of new biological insights around the importance and nature of immune checkpoints that are able to reverse down-regulation of anti-tumor immunity.

AREAS COVERED

An overview of the preclinical and recent clinical trial data on key immuno-regulatory agents currently in development, including antibody targeting of cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed death receptor 1 (PD-1) on T-lymphocytes and its principal ligand (PD-L1) on tumor cells as well as immune agonists (e.g., anti-CD40).

EXPERT OPINION

Durable long-term responses in some patients with advanced melanoma, initially with ipilimumab (anti-CTLA-4) and more recently antibodies targeting either PD-1 or PD-L1 in patients with melanoma and renal cancer, non-small-cell lung, bladder and head and neck cancers with less toxicity, have provided real optimism that immunotherapeutic approaches can improve outcomes in a wide range of cancer. The manageable tolerability of PD-1-pathway blockers and their unique mechanism of action are encouraging combination approaches. Current efforts focus on registration trials of single agents plus combinations in many different tumor types and treatment settings and identifying and developing predictive biomarkers of immunological response.

New clinical advances in immunotherapy for the treatment of solid tumours

Advances in understanding the mechanisms of cancer cells for evading the immune system surveillance, including how the immune system modulates the phenotype of tumours, have allowed the development of new therapies that benefit from this complex cellular network to specifically target and destroy cancer cells. Immunotherapy researchers have mainly focused on the discovery of tumour antigens that could confer specificity to immune cells to detect and destroy cancer cells, as well as on the mechanisms leading to an improved activation of effector immune cells. The Food and Drug Administration approval in 2010 of ipilumumab for melanoma treatment and of pembrolizumab in 2014, monoclonal antibodies against T-lymphocyte-associated antigen 4 and programmed cell death 1, respectively, are encouraging examples of how research in this area can successfully translate into clinical use with promising results. Currently, several ongoing clinical trials are in progress testing new anti-cancer therapies based on the enhancement of immune cell activity against tumour antigens. Here we discuss the general concepts related to immunotherapy and the recent application to the treatment of cancer with positive results that support their consideration of clinical application to patients.

Does It MEK a Difference? Understanding Immune Effects of Targeted Therapy

BRAF inhibitor (BRAFi) treatment enhances antitumor immunity, but is associated with increased intratumoral PD-L1 expression. MEK inhibitors (MEKi) may alter T-cell function; however, recent studies demonstrate preserved T-cell infiltrate during treatment with BRAFi/MEKi. These data have important implications for combining BRAFi/MEKi and checkpoint blockade in the treatment of melanoma.

Antibody-Dependent Cellular Cytotoxicity Activity of a Novel Anti-PD-L1 Antibody Avelumab (MSB0010718C) on Human Tumor Cells

Several anti-PD-1/PD-L1 monoclonal antibodies (mAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these mAbs is to inhibit PD-1 on immune cells interacting with PD-L1 on tumor cells. These mAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective mAb-mediated cancer therapies. A fully human anti-PD-L1 mAb would potentially be able to block PD-1/PD-L1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 mAb. The studies reported here demonstrate (i) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (ii) IFNγ can enhance tumor cell PD-L1 expression and, in some cases, enhance ADCC tumor cell lysis; (iii) purified NK cells are potent effectors for avelumab; (iv) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (v) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (vi) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 mAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity.

Immunomodulatory effect of peritumorally administered interferon-beta on melanoma through tumor-associated macrophages

An imbalance of immunosuppressive cells and cytotoxic cells plays an important role in the tumor-bearing host. Together with regulatory T cells (Tregs), tumor-associated macrophages (TAMs) play roles in maintaining the tumor microenvironment. Since interferon beta (IFN-β) has been clinically used for the treatment of malignant melanoma, we investigated the immunomodulatory effect of IFN-β during melanoma growth to elucidate the effects of IFN-β on the tumor microenvironment by using the B16F10 melanoma model. Peritumorally administered IFN-β significantly decreased the mRNA expression and production of Th2-related chemokines, which suppressed the recruitment of Tregs in B16F10 melanoma. Since the administration of IFN-β augments the expression of PD-1 on TILs, the co-administration of anti-PD-1 Ab augmented the therapeutic effect of IFN-β for the treatment of B16F10 melanoma. Moreover, in parallel with the mouse model, in the human system, IFN-β decreased the production of Th2-related chemokines and augmented the production of Th1-related chemokines from monocyte-derived M2 macrophages. Since these immunomodulatory effects of IFN-β on macrophages were also observed in the lesional skin of human in-transit melanoma, our present data suggest one of the possible immunomodulatory effects of IFN-β and support the possibility of IFN-β in combination with anti-PD-1 Ab for the treatment of melanoma.

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.

Noninvasive Imaging of Tumor PD-L1 Expression Using Radiolabeled Anti-PD-L1 Antibodies

Antibodies that block the interaction between programmed death ligand 1 (PD-L1) and PD-1 have shown impressive antitumor activity. Patients with tumors expressing PD-L1 are most likely to respond to this treatment. The aim of our study was to develop a noninvasive imaging technique to determine tumor PD-L1 expression in vivo. This could allow selection of patients that are most likely to benefit from anti-PD-1/PD-L1 treatment and to monitor PD-L1 expression during therapy. The monoclonal antibody PD-L1.3.1 was radiolabeled with Indium-111 ((111)In) and characterized using PD-L1-expressing MDA-MB-231 cells. Subsequently, the optimal antibody dose and time point for imaging was determined in mice with MDA-MB-231 xenografts. Finally, SPECT/CT imaging was performed in xenograft models with different PD-L1 expression levels and tumor sections were analyzed for PD-L1 expression using IHC. The optimal antibody dose of (111)In-PD-L1.3.1 (Kd = 1 nmol/L) for SPECT/CT imaging was ≤1 μg. Highest tumor-to-normal tissue contrast was obtained at days 3 and 7 after injection. (111)In-PD-L1.3.1 SPECT/CT showed efficient accumulation in high PD-L1-expressing tumors (MDA-MB-231 and SK-Br-3), whereas no specific uptake was observed in tumors with low or no detectable levels of PD-L1 (SUM149, BT474, and MCF-7). SPECT/CT and autoradiography showed a very heterogeneous distribution of (111)In-PD-L1.3.1 within the tumor. In conclusion, this is the first study showing the feasibility of noninvasive in vivo imaging of PD-L1 expression in tumors. (111)In-PD-L1.3.1 showed efficient and specific uptake in PD-L1 expressing xenografts. This technique may enable patient selection for PD-1 and PD-L1-targeted therapy.

Phase I Study of Pembrolizumab (MK-3475; Anti-PD-1 Monoclonal Antibody) in Patients with Advanced Solid Tumors

PURPOSE

This phase I study evaluated the safety, maximum tolerated dose, antitumor activity, and pharmacokinetics and pharmacodynamics of pembrolizumab in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

In a 3 + 3 dose escalation study, 10 patients received pembrolizumab 1, 3, or 10 mg/kg intravenously every 2 weeks until progression or intolerable toxicity. Seven additional patients received 10 mg/kg every 2 weeks. Thirteen patients participated in a 3-week intrapatient dose escalation (dose range, 0.005-10 mg/kg) followed by 2 or 10 mg/kg every 3 weeks. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

RESULTS

No dose-limiting toxicities were observed. Maximum administered dose was 10 mg/kg every 2 weeks. One patient with melanoma and one with Merkel cell carcinoma experienced complete responses of 57 and 56+ weeks' duration, respectively. Three patients with melanoma experienced partial responses. Fifteen patients with various malignancies experienced stable disease. One patient died of cryptococcal infection 92 days after pembrolizumab discontinuation, following prolonged corticosteroid use for grade 2 gastritis considered drug related. Pembrolizumab exhibited pharmacokinetic characteristics typical of humanized monoclonal antibodies. Maximum serum target engagement was reached with trough levels of doses greater than or equal to 1 mg/kg every 3 weeks. Mechanism-based translational models with a focus on intratumor exposure prediction suggested robust clinical activity would be observed at doses ≥2 mg/kg every 3 weeks.

CONCLUSIONS

Pembrolizumab was well tolerated and associated with durable antitumor activity in multiple solid tumors. The lowest dose with full potential for antitumor activity was 2 mg/kg every 3 weeks.

Swinging for the Fences: Long-Term Survival With Ipilimumab in Metastatic Melanoma

A 40-year-old man with stage III melanoma arising from his left shoulder underwent wide local excision, sentinel lymph node biopsy, and lymph node dissection. Nine months after receiving adjuvant biochemotherapy with cisplatin, vinblastine, dacarbazine, interleukin-2 (IL-2), and interferon alfa as part of a clinical trial, he developed headaches and right-hand weakness and was found to have a 2-cm left parietal CNS metastasis. A comprehensive staging workup identified multiple nonspecific subcentimeter pulmonary nodules. The brain mass was resected and confirmed to be metastatic melanoma; the surgical bed was treated with stereotactic radiosurgery. He was monitored off therapy, but 5 months later, he developed a second left parietal CNS metastasis and enlarging lung nodules. The new brain lesion was treated with stereotactic radiosurgery, and he began systemic therapy with ipilimumab on a clinical trial. After the third dose, he presented with headache, nausea, and vomiting; a brain magnetic resonance imaging scan showed left anterior temporal enhancement, possibly representing new disease. His symptoms improved with a course of corticosteroids. Restaging of the chest showed a mixed response among the pulmonary nodules. After tapering off corticosteroids, he received the fourth dose of ipilimumab, which was complicated by grade 3 transaminitis and hypophysitis with documented hypothyroidism and adrenal insufficiency. They were managed with corticosteroids and thyroid and adrenal hormone replacement. Restaging scans showed further disease regression except for new confluent enhancing nodules and edema in the left temporal lobe. Craniotomy and resection of this area showed only necrotic tissue with no viable melanoma cells. Nine years after treatment with ipilimumab, he is alive and shows no evidence of melanoma on the basis of annual computed tomography scans of the chest, abdomen, and pelvis and magnetic resonance imaging scans of the brain. He has full neurologic function but still requires hormone replacement for persistent hypopituitarism.

Melanoma-intrinsic β-catenin signalling prevents anti-tumour immunity

Melanoma treatment is being revolutionized by the development of effective immunotherapeutic approaches. These strategies include blockade of immune-inhibitory receptors on activated T cells; for example, using monoclonal antibodies against CTLA-4, PD-1, and PD-L1 (refs 3-5). However, only a subset of patients responds to these treatments, and data suggest that therapeutic benefit is preferentially achieved in patients with a pre-existing T-cell response against their tumour, as evidenced by a baseline CD8(+) T-cell infiltration within the tumour microenvironment. Understanding the molecular mechanisms that underlie the presence or absence of a spontaneous anti-tumour T-cell response in subsets of cases, therefore, should enable the development of therapeutic solutions for patients lacking a T-cell infiltrate. Here we identify a melanoma-cell-intrinsic oncogenic pathway that contributes to a lack of T-cell infiltration in melanoma. Molecular analysis of human metastatic melanoma samples revealed a correlation between activation of the WNT/β-catenin signalling pathway and absence of a T-cell gene expression signature. Using autochthonous mouse melanoma models we identified the mechanism by which tumour-intrinsic active β-catenin signalling results in T-cell exclusion and resistance to anti-PD-L1/anti-CTLA-4 monoclonal antibody therapy. Specific oncogenic signals, therefore, can mediate cancer immune evasion and resistance to immunotherapies, pointing to new candidate targets for immune potentiation.

Identification and Characterization of MEDI4736, an Antagonistic Anti-PD-L1 Monoclonal Antibody

Programmed cell-death 1 ligand 1 (PD-L1) is a member of the B7/CD28 family of proteins that control T-cell activation. Many tumors can upregulate expression of PD-L1, inhibiting antitumor T-cell responses and avoiding immune surveillance and elimination. We have identified and characterized MEDI4736, a human IgG1 monoclonal antibody that binds with high affinity and specificity to PD-L1 and is uniquely engineered to prevent antibody-dependent cell-mediated cytotoxicity. In vitro assays demonstrate that MEDI4736 is a potent antagonist of PD-L1 function, blocking interaction with PD-1 and CD80 to overcome inhibition of primary human T-cell activation. In vivo MEDI4736 significantly inhibits the growth of human tumors in a novel xenograft model containing coimplanted human T cells. This activity is entirely dependent on the presence of transplanted T cells, supporting the immunological mechanism of action for MEDI4736. To further determine the utility of PD-L1 blockade, an anti-mouse PD-L1 antibody was investigated in immunocompetent mice. Here, anti-mouse PD-L1 significantly improved survival of mice implanted with CT26 colorectal cancer cells. The antitumor activity of anti-PD-L1 was enhanced by combination with oxaliplatin, which resulted in increased release of HMGB1 within CT26 tumors. Taken together, our results demonstrate that inhibition of PD-L1 function can have potent antitumor activity when used as monotherapy or in combination in preclinical models, and suggest it may be a promising therapeutic approach for the treatment of cancer. MEDI4736 is currently in several clinical trials both alone and in combination with other agents, including anti-CTLA-4, anti-PD-1, and inhibitors of IDO, MEK, BRAF, and EGFR.

Adverse events of monoclonal antibodies used for cancer therapy

In 1997, the first monoclonal antibody (MoAb), the chimeric anti-CD20 molecule rituximab, was approved by the US Food and Drug administration for use in cancer patients. Since then, the panel of MoAbs that are approved by international regulatory agencies for the treatment of hematopoietic and solid malignancies has continued to expand, currently encompassing a stunning amount of 20 distinct molecules for 11 targets. We provide a brief scientific background on the use of MoAbs in cancer therapy, review all types of monoclonal antibodies-related adverse events (e.g., allergy, immune-related adverse events, cardiovascular adverse events, and pulmonary adverse events), and discuss the mechanism and treatment of adverse events.

Nivolumab and Olaparib

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Systemic Therapy in Metastatic Melanoma

New targeted treatments and therapies for metastatic melanoma are improving patient prognosis and survival.

Stereotactic radiation therapy combined with immunotherapy: augmenting the role of radiation in local and systemic treatment

Stereotactic radiosurgery and stereotactic body radiation therapy are two contemporary radiation modalities that can treat tumors in any area of the body using highly focused radiation. Recently, immunotherapy has established itself as a viable and powerful anticancer treatment. In this review we detail the rationale supporting a combination of immunotherapy and stereotactic radiation. Additionally, we discuss the evidence for the immune stimulatory effects of focused radiation and the role that radiation may play in enhancing the systemic treatment effects of immunotherapy.

Long-term survival in advanced melanoma patients using repeated therapies: successive immunomodulation improving the odds?

Background

Patients with advanced metastatic melanoma are often confronted with little prospect of medium- to longer-term survival by any currently available therapeutic means. However, most clinicians are aware of exceptional cases where survival defies the notion of futility. Prolonged survival from immunotherapies, including interleukin-2, vaccines and antibodies to cytotoxic lymphocyte antigen-4, and programmed death-1 receptor inhibitory monoclonal antibody, implies a role for immune system modulation. We aimed to identify cases where exceptional survival from advanced melanoma occurred prior to recent novel therapies to facilitate better understanding of this phenomenon.

Methods

Cases of long-term survival of ≥3 years’ duration (from diagnosis of metastatic disease) were identified from the database of one clinician; these cases were treated before the availability of newer immunotherapies, and they were documented and examined. A literature search for reported outcome measures from published studies using older and recent therapies for advanced melanoma was conducted to enable the comparison of data.

Results

Eighteen cases were identified that identified survival of ≥3 years’ duration from metastatic disease (12 American Joint Committee on Cancer [AJCC] Stage IV cases; six AJCC III cases) diagnosis. These were assessed and reported to detail the clinical course. Standard clinical prognostication methods predicted high risk of early mortality in those patients. No identifiable differences could be detected between these and other patients with similar patterns of disease. At evaluation, 17 patients (94%) had survived ≥5 years, and eleven patients (61%) had survived ≥10 years (range: 3–15 years). The median survival duration with metastatic disease was 11 years; 15 remained alive and three had died. Published studies of melanoma therapies were tabled for comparison.

Conclusion

The fact that 18 cases of exceptional survival in advanced melanoma were identified is remarkable in itself. Even with recent therapies, the factors for improved survival remain enigmatic; however, one apparent common denominator in most cases was the persistent use of repeated therapies to reduce tumor bulk, induce tumor necrosis, and/or cause immunostimulation. These cases are instructive, suggesting manipulation of an established, endogenous, existing immune response. These observations provide practical evidence that the course for any patient with advanced melanoma at the outset should be considered unpredictable, open to immunomanipulation, and thus not uniformly fatal. The findings were compared and interpreted with reported newer immunotherapeutic approaches.

Evolving Concepts: Immunity in Oncology from Targets to Treatments

Cancer is associated with global immune suppression of the host. Malignancy-induced immune suppressive effect can be circumvented by blocking the immune checkpoint and tip the immune balance in favor of immune stimulation and unleash cytotoxic effects on cancer cells. Human antibodies directed against immune checkpoint proteins: cytotoxic T lymphocytes antigen-4 (CTLA-4) and programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), have shown therapeutic efficacy in advanced melanoma and non-small-cell lung cancer and other malignancies. Immune check point blockade antibodies lead to diminished tolerance to self and enhanced immune ability to recognize and eliminate cancer cells. As a class these agents have immune-related adverse events due to decreased ability of effector immune cells to discriminate between self and non-self. Seventy percent of patients participating in clinical trials have experienced anticancer activities and varying degrees of immune mediated dose-limiting side effects.

Anti-programmed cell death protein-1/ligand-1 therapy in different cancers

Immunologic checkpoint blockade with antibodies against the programmed cell death protein-1 (PD-1) or its ligand (PD-L1) is an effective method for reversing cancer immunosuppression and thereby promoting immune responses against several cancer types. Anti-PD-1 and anti-PD-L1 antibodies have resulted in long-term responses with minimal side effects in significant numbers of patients with melanoma, lung, kidney, bladder and triple-negative breast cancer, as well as in chemotherapy-refractory Hodgkin disease. There is already evidence from at least one randomised trial that anti-PD-1 therapy is superior to chemotherapy in the treatment of patients with metastatic melanoma, and two anti-PD-1 antibodies, pembrolizumab and nivolumab, have been approved by the US Food and Drug Administration for the treatment of patients previously treated for metastatic melanoma. It is anticipated that approvals by drug regulatory bodies will be forthcoming in several cancers in the next months.

Melanoma

Melanoma is a common cancer in the Western world with an increasing incidence. Sun exposure is still considered to be the major risk factor for melanoma. The prognosis of patients with malignant (advanced-stage) melanoma differs widely between countries, but public campaigns advocating early detection have led to significant reductions in mortality rates. As well as sun exposure, distinct genetic alterations have been identified as associated with melanoma. For example, families with melanoma who have germline mutations in CDKN2A are well known, whereas the vast majority of sporadic melanomas have mutations in the mitogen-activated protein kinase cascade, which is the pathway with the highest oncogenic and therapeutic relevance for this disease. BRAF and NRAS mutations are typically found in cutaneous melanomas, whereas KIT mutations are predominantly observed in mucosal and acral melanomas. GNAQ and GNA11 mutations prevail in uveal melanomas. Additionally, the PI3K-AKT-PTEN pathway and the immune checkpoint pathways are important. The finding that programmed cell death protein 1 ligand 1 (PDL1) and PDL2 are expressed by melanoma cells, T cells, B cells and natural killer cells led to the recent development of programmed cell death protein 1 (PD1)-specific antibodies (for example, nivolumab and pembrolizumab). Alongside other new drugs - namely, BRAF inhibitors (vemurafenib and dabrafenib) and MEK inhibitors (trametinib and cobimetinib) - these agents are very promising and have been shown to significantly improve prognosis for patients with advanced-stage metastatic disease. Early signs are apparent that these new treatment modalities are also improving long-term clinical benefit and the quality of life of patients. This Primer summarizes the current understanding of melanoma, from mechanistic insights to clinical progress. For an illustrated summary of this Primer, visit: http://go.nature.com/vX2N9s.

Clinical applications of PD-1-based therapy: a focus on pembrolizumab (MK-3475) in the management of melanoma and other tumor types

Preclinical work has led to an increased understanding of the immunomodulatory mechanisms involved in the regulation of the antitumor response in a variety of tumor types. PD-1 (programmed death 1) appears to be a key checkpoint involved in immune suppression in the tumor microenvironment, even in diseases not previously thought to be sensitive to immune manipulation. More recently, the subsequent clinical development of PD-1-based therapy has resulted in a major breakthrough in the field of oncology. Pembrolizumab, a humanized highly selective IgG4 anti-PD-1 monoclonal antibody, was recently approved for the treatment of advanced melanoma based on promising early-phase clinical data. Encouraging results have also been seen in other malignancies, and PD-1-targeted therapies are likely to markedly change the treatment landscape. Future work will center on rationally designed combination strategies in order to potentiate the antitumor immune response and overcome mechanisms of resistance.

Corticosteroids augment BRAF inhibitor vemurafenib induced lymphopenia and risk of infection

We have previously demonstrated an impact of the BRAF inhibitor vemurafenib on patient lymphocyte counts. In the current study, the extent to which concomitant use of corticosteroids in BRAF inhibitor treated patients affects lymphocyte counts and predisposes to infection was investigated. A cohort of 102 patients receiving either the selective BRAF inhibitor vemurafenib or dabrafenib was analyzed. The amount of patients receiving either medication with or without systemic corticosteroids (dexamethasone) was determined and lymphocyte counts before and under therapy assessed. Additionally, the number and severity of infections occurring in these groups was analyzed. Vemurafenib treatment led to a considerable decrease in lymphocyte cell counts, with 62.3% of patients having lymphopenia. Dabrafenib treated patients only rarely demonstrated lymphopenia (12.5%). Dexamethasone co-administration further diminished lymphocyte counts. Lymphopenias were observed in 84.6% of patients receiving vemurafenib and dexamethasone. In our cohort, infections were noted in 9 patients, 4 of these were severe and 2 eventually fatal. All 9 cases with infections demonstrated lymphopenia, 8 of these had received dexamethasone and 7 of these a therapy with vemurafenib. Our findings demonstrate a significant lymphopenia in patients treated with the BRAF inhibitor vemurafenib, which is further augmented by dexamethasone and predisposes to infection. If validated in other studies, risk of infection should be considered when applying corticosteroids in combination with BRAF inhibitors, in particular vemurafenib.

The therapeutic promise of disrupting the PD-1/PD-L1 immune checkpoint in cancer: unleashing the CD8 T cell mediated anti-tumor activity results in significant, unprecedented clinical efficacy in various solid tumors

The role of immune checkpoints in modulating the magnitude as well as the functional profile of T cell responses is increasingly understood in molecular detail. Antibody-mediated blockade of co-inhibitory receptors has been shown to restore T cell function in both chronic viral infections and cancer. The latter has been successfully translated to new therapeutic options in the treatment of cancer. Indeed, monoclonal antibodies blocking either CTLA-4 or PD-1 have recently been approved for the treatment of metastatic melanoma in the United States, Europe and Japan. In this commentary, we summarize and put into perspective five letters recently published back to back in the November 27 (2014) issue of Nature reporting on different immunological and clinical aspects of blockade of the PD-1/PD-L1 pathway in tumor bearing hosts. Notably, treatment with anti-PD-L1 blocking antibody was shown result in profound clinical responses in patients with several solid tumor including bladder, lung and head and neck carcinomas among others. These five simultaneous publications highlight the tremendous therapeutic potential of targeting the PD-1/PD-L1 immune checkpoint and emphasize the need to identify appropriate biomarkers to guide their optimal clinical application.

A systematic review of immune-related adverse event reporting in clinical trials of immune checkpoint inhibitors

BACKGROUND

There are limited data about the quality of immune-related adverse event (irAE) reporting in immune checkpoint inhibitor (ICI) clinical trial publications.

METHODS

A systematic search of citations from Medline, EMBASE and Cochrane databases identified prospective clinical trials involving ICIs in advanced solid tumors from 2003 to 2013. A 21-point quality score (QS) was adapted from the CONSORT harms extension statement. Linear regression was used to identify factors associated with quality reporting.

RESULTS

After a review of 2628 articles, 50 trial reports were included, with ICIs as either monotherapy (54%) or part of a combination regimen (46%). The mean QS was 11.21 points (range 3.50-17.50 points). The median grade 3/4 AE rate reported was 21% (range 0%-66%) and 29/50 (58%) trials concluded that irAEs were tolerable. Multivariate regression analysis revealed that year of publication (within last 5 years, P = 0.01) and journal impact factor >15 (P = 0.004) were associated with higher QS. Complete reporting of specific characteristics of irAEs including onset, management and reversibility were reported by 14%, 8% and 6% of studies, respectively. The incidence of grade 3/4 adverse events was higher for inhibitors against CTLA-4 compared with other immune checkpoints (P < 0.001).

CONCLUSIONS

The reporting of irAEs is suboptimal. A standardized reporting method of irAEs that accounts for tolerability, management and reversibility is needed and would enable a more precise evaluation of the therapeutic risk benefit ratio of ICIs.

Subverting the B7-H1/PD-1 pathway in advanced melanoma and kidney cancer

Ligands for inhibitory immune receptors on T cells may be constitutively expressed on tumor cells or host cells in tumor microenvironment as a consequence of adaptive immunity. Programmed death 1 (PD-1) is 1 such receptor on T cells, which functions as a negative regulator of T cell activity. Tumors that up-regulate programmed death ligand 1 (PD-L1) (B7-H1) may abrogate the host's effector T cell antitumor response. Higher tumoral PD-L1 expression has been linked with inferior clinical outcomes. Multiple cancers including renal cell cancers (RCCs) and melanomas have relatively high levels of PD-L1 on the cell surface. Early evaluations of antibodies that block the interaction of PD-1 and PD-L1 have shown efficacy and a favorable tolerability profile with notable inflammatory toxicities that are generally manageable. Upward of 30% of RCC patients and 50% of melanoma patients achieve objective responses. Durable responses can occur, even in some patients who have discontinued treatment. The developing investigation of PD-1/PD-L1 pathway-blocking agents in RCC and melanoma will likely alter our approaches to the treatment of these 2 deadly diseases.

Blockade of the B7-H1/PD-1 pathway as a basis for combination anticancer therapy

Signaling through programmed death 1 (PD-1) expressed by activated T lymphocytes inhibits their function and is a major mechanism for suppressing antitumor T cell responses in the tumor microenvironment. Recent clinical trials show that blockade of the B7-H1(programmed death ligand 1 [PD-L1])/PD-1 pathway with anti-PD-1 or anti-PD-L1 is active in several malignancies and produces durable responses in a subset of patients. Clinical response to these agents may be limited by other mechanisms of T-lymphocyte suppression in the tumor microenvironment, or absence of a significant tumor-specific T cell response in the tumor. Combinations with other therapies are likely to address at least several of the major mechanisms of resistance, supported by abundant preclinical data in animal tumor model systems. The combination of anti-PD-1 with anti-CTLA-4 demonstrated promising activity in metastatic melanoma and is being tested in multiple other malignancies. Other combinations based on PD-1/PD-L1 blockade are either in early clinical development or in planning stages. Many of the combinations based on PD-1/PD-L1 blockade are expected to produce a higher incidence of autoimmune-like toxicities, but clinical experience with agents such as ipilimumab suggests that toxicities will be manageable and reversible and the overall risk-benefit ratio will be acceptable.

Immune checkpoint blockade: a common denominator approach to cancer therapy

The immune system recognizes and is poised to eliminate cancer but is held in check by inhibitory receptors and ligands. These immune checkpoint pathways, which normally maintain self-tolerance and limit collateral tissue damage during anti-microbial immune responses, can be co-opted by cancer to evade immune destruction. Drugs interrupting immune checkpoints, such as anti-CTLA-4, anti-PD-1, anti-PD-L1, and others in early development, can unleash anti-tumor immunity and mediate durable cancer regressions. The complex biology of immune checkpoint pathways still contains many mysteries, and the full activity spectrum of checkpoint-blocking drugs, used alone or in combination, is currently the subject of intense study.

TIGIT and PD-1 impair tumor antigen-specific CD8⁺ T cells in melanoma patients

T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen-specific (TA-specific) CD8⁺ T cells and CD8⁺ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8⁺ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8⁺ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1⁺TIM-3⁺ TA-specific CD8⁺ T cells. PD-1⁺TIGIT⁺, PD-1⁻TIGIT⁺, and PD-1⁺TIGIT⁻ CD8⁺ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand-expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8⁺ T cells and CD8⁺ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8⁺ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8⁺ T cell responses in patients with advanced melanoma.

Inducible but not constitutive expression of PD-L1 in human melanoma cells is dependent on activation of NF-κB

Monoclonal antibodies against immune checkpoint blockade have proven to be a major success in the treatment of melanoma. The programmed death receptor-1 ligand-1 (PD-L1) expression on melanoma cells is believed to have an inhibitory effect on T cell responses and to be an important escape mechanism from immune attack. Previous studies have shown that PD-L1 can be expressed constitutively or can be induced by IFN-γ secreted by infiltrating lymphocytes. In the present study we have investigated the mechanism underlying these two modes of PD-L1 expression in melanoma cells including cells that had acquired resistance to the BRAF inhibitor vemurafenib. PD-L1 expression was examined by flow cytometry and immunoblotting. Specific inhibitors and siRNA knockdown approaches were used to examine the roles of the RAF/ MEK, PI3K, NF-κB, STAT3 and AP1/ c-Jun pathways. IFN-γ inducible expression of PD-L1 was dependent on NF-κB as shown by inhibition with BMS-345541, an inhibitor of IκB and the BET protein inhibitor I-BET151, as well as by siRNA knockdown of NF-κB subunits. We were unable to implicate the BRAF/MEK pathway as major regulators in PD-L1 expression on vemurafenib resistant cells. Similarly the PI3K/AKT pathway and the transcription factors STAT3 and c-Jun had only minor roles in IFN-γ induced expression of PD-L1. The mechanism underlying constitutive expression remains unresolved. We suggest these results have significance in selection of treatments that can be used in combination with monoclonal antibodies against PD1, to enhance their effectiveness and to reduce inhibitory effects melanoma cells have against cytotoxic T cell activity.

Several immune escape patterns in non-Hodgkin's lymphomas

Follicular Lymphomas (FL) and diffuse large B cell lymphomas (DLBCL) must evolve some immune escape strategy to develop from lymphoid organs, but their immune evasion pathways remain poorly characterized. We investigated this issue by transcriptome data mining and immunohistochemistry (IHC) of FL and DLBCL lymphoma biopsies. A set of genes involved in cancer immune-evasion pathways (Immune Escape Gene Set, IEGS) was defined and the distribution of the expression levels of these genes was compared in FL, DLBCL and normal B cell transcriptomes downloaded from the GEO database. The whole IEGS was significantly upregulated in all the lymphoma samples but not in B cells or other control tissues, as shown by the overexpression of the PD-1, PD-L1, PD-L2 and LAG3 genes. Tissue microarray immunostainings for PD-1, PD-L1, PD-L2 and LAG3 proteins on additional biopsies from 27 FL and 27 DLBCL patients confirmed the expression of these proteins. The immune infiltrates were more abundant in FL than DLBCL samples, and the microenvironment of FL comprised higher rates of PD-1⁺ lymphocytes. Further, DLBCL tumor cells comprised a higher proportion of PD-1+, PD-L1⁺, PD-L2⁺ and LAG3⁺ lymphoma cells than the FL tumor cells, confirming that DLBCL mount immune escape strategies distinct from FL. In addition, some cases of DLBCL had tumor cells co-expressing both PD-1, PD-L1 and PD-L2. Among the DLBCLs, the activated B cell (ABC) subtype comprised more PD-L1⁺ and PD-L2⁺ lymphoma cells than the GC subtype. Thus, we infer that FL and DLBCL evolved several pathways of immune escape.

Trial Watch: Immunomodulatory monoclonal antibodies for oncological indications

Immunomodulatory monoclonal antibodies (mAbs) differ from their tumor-targeting counterparts because they exert therapeutic effects by directly interacting with soluble or (most often) cellular components of the immune system. Besides holding promise for the treatment of autoimmune and inflammatory disorders, immunomodulatory mAbs have recently been shown to constitute a potent therapeutic weapon against neoplastic conditions. One class of immunomodulatory mAbs operates by inhibiting safeguard systems that are frequently harnessed by cancer cells to establish immunological tolerance, the so-called "immune checkpoints." No less than 3 checkpoint-blocking mAbs have been approved worldwide for use in oncological indications, 2 of which during the past 12 months. These molecules not only mediate single-agent clinical activity in patients affected by specific neoplasms, but also significantly boost the efficacy of several anticancer chemo-, radio- or immunotherapies. Here, we summarize recent advances in the development of checkpoint-blocking mAbs, as well as of immunomodulatory mAbs with distinct mechanisms of action.

Immune checkpoint blockade in hematologic malignancies

Therapeutic blockade of immune checkpoint pathways, in particular cytotoxic T-lymphocyte associated protein 4 and programmed-death 1 (PD-1), has become a paradigm-shifting treatment in solid tumor oncology. Hematologic malignancies (HMs), many of which are known to have clinically exploitable immune sensitivity, are a natural target for this type of treatment. Several clinical trials of checkpoint blockade have been conducted in HM, with preliminary results suggesting the therapeutic usefulness of this approach across several tumor types. In particular, the results of PD-1 blockade in Hodgkin lymphoma (HL) are remarkable, and raise hope that it may alter the treatment landscape in this disease. However, numerous questions remain about the optimal role of checkpoint blockade both in HL and beyond. Those questions are the focus of this review, in the hope that, if we are at the dawn of a new day in HM immunotherapy, we may begin to envision its morning.

[Targeted therapies for melanoma]

Since the discovery of activating mutations in the BRAF oncogene and also stimulation of immune mediated antitumor response in melanoma, there has been remarkable progress in the development of targeted therapies for unresectable and metastatic melanoma. This article addresses the latest developments of BRAF/MEK/ERK pathway signaling. In addition, the development of drugs to attack alternative mutations in melanoma, such as NRAS and KIT is described. Strategies for the management of BRAF inhibitor resistance, such as with combination therapy, are outlined. Antitumor immune therapies with monoclonal antibodies such as ipilimumab which acts by promoting T-cell activation or antibody blockade of programmed death-1 (PD-1) led to a long term response in metastatic melanoma. Results of latest clinical studies including the toxicity profile are described. Due to selective kinase inhibitors and immune checkpoint blockade, the therapy of unresectable metastatic melanoma has greatly improved and long-term survival of patients with metastatic melanoma seems a real possibility.

Survival, Durable Response, and Long-Term Safety in Patients With Previously Treated Advanced Renal Cell Carcinoma Receiving Nivolumab

PURPOSE

Blockade of the programmed death-1 inhibitory cell-surface molecule on immune cells using the fully human immunoglobulin G4 antibody nivolumab mediates tumor regression in a portion of patients with advanced treatment-refractory solid tumors. We report clinical activity, survival, and long-term safety in patients with advanced renal cell carcinoma (RCC) treated with nivolumab in a phase I study with expansion cohorts.

PATIENTS AND METHODS

A total of 34 patients with previously treated advanced RCC, enrolled between 2008 and 2012, received intravenous nivolumab (1 or 10 mg/kg) in an outpatient setting once every two weeks for up to 96 weeks and were observed for survival and duration of response after treatment discontinuation.

RESULTS

Ten patients (29%) achieved objective responses (according to RECIST [version 1.0]), with median response duration of 12.9 months; nine additional patients (27%) demonstrated stable disease lasting > 24 weeks. Three of five patients who stopped treatment while in response continued to respond for ≥ 45 weeks. Median overall survival in all patients (71% with two to five prior systemic therapies) was 22.4 months; 1-, 2-, and 3-year survival rates were 71%, 48%, and 44%, respectively. Grade 3 to 4 treatment-related adverse events occurred in 18% of patients; all were reversible.

CONCLUSION

Patients with advanced treatment-refractory RCC treated with nivolumab demonstrated durable responses that in some responders persisted after drug discontinuation. Overall survival is encouraging, and toxicities were generally manageable. Ongoing randomized clinical trials will further assess the impact of nivolumab on overall survival in patients with advanced RCC.

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.

A phase I study of MEDI4736, NNT-PD-L1 antibody in patients with advanced solid tumors

A review and critical consideration of immunotherapeutical concepts in non-small cell lung cancer (NSCLC) is given. Nivolumab represents a promising option in various malignancies with more results exceeding treatment of metastatic malignant melanoma eagerly awaited.