Cancer immunotherapy by immune checkpoint blockade and its advanced application using bio-nanomaterials

Cancer is the second leading cause of death worldwide. Traditional approaches, such as surgery, chemotherapy, and radiotherapy have been the main cancer therapeutic modalities in recent years. Cancer immunotherapy is a novel therapeutic modality that potentiates the immune responses of patients against malignancy. Immune checkpoint proteins expressed on T cells or tumor cells serve as a target for inhibiting T cell overactivation, maintaining the balance between self-reactivity and autoimmunity. Tumors essentially hijack the immune checkpoint pathway in order to survive and spread. Immune checkpoint inhibitors (ICIs) are being developed as a result to reactivate the anti-tumor immune response. Recent advances in nanotechnology have contributed to the development of successful, safe, and efficient anticancer drug systems based on nanoparticles. Nanoparticle-based cancer immunotherapy overcomes numerous challenges and offers novel strategies for improving conventional immunotherapies. The fundamental and physiochemical properties of nanoparticles depend on various cancer therapeutic strategies, such as chemotherapeutics, nucleic acid-based treatments, photothermal therapy, and photodynamic agents. The review discusses the use of nanoparticles as carriers for delivering immune checkpoint inhibitors and their efficacy in cancer combination therapy.

Interleukin-2, Ipilimumab, and Anti-PD-1: clinical management and the evolving role of immunotherapy for the treatment of patients with metastatic melanoma

Treatment of metastatic melanoma has changed dramatically in the past 5 years with the approval of six new agents (vemurafenib, dabrafenib, trametinib, ipilimumab, pembrolizumab, and nivolumab) by the US Food and Drug Administration (FDA). This review will compare the immunotherapies recently approved by the FDA (ipilimumab, nivolumab and pembrolizumab) with the long-approved immunotherapy, interleukin-2. Additional consideration will be given to the evolving landscape, including the opportunities for combination regimens. Immunotherapies have distinct mechanisms of action and unique response kinetics that differ from conventional cytotoxic and targeted therapies, and have a range of adverse events that can be safely managed by experienced health-care providers. Data suggest immunotherapies can result in long-term survival in a proportion of patients. This dynamic and evolving field of immunotherapy for melanoma will continue to offer challenges in terms of optimal patient management for the foreseeable future.

Exploratory analysis of clinical benefit of ipilimumab and nivolumab treatment in patients with metastatic melanoma from a single institution

PURPOSE

We retrospectively analysed overall survival (OS) and potential predictive biomarkers of OS in patients with metastatic melanoma treated with ipilimumab plus nivolumab in a single institution.

METHODS AND PATIENTS

Electronic medical records of patients with advanced melanoma receiving ≥ 1 dose of a combined ipilimumab plus nivolumab regimen between March 3, 2016 and March 7, 2020 in a single institution, were reviewed. OS was analysed using the Kaplan-Meier method. Sub-group analyses were conducted to examine several endpoints according to relevant clinical, molecular and pathological variables using logistic and Cox models.

RESULTS

Forty-four cases were reviewed, 38 (86.4%), of whom had cutaneous melanoma, 21 (47.7%) were BRAF mutant, 21 (47.7%) presented high lactate dehydrogenase (LDH) values, 23 (52.3%) had ≥ 3 disease sites, and 10 (22.7%) patients had brain metastases. The median follow-up was 37.7 months, and the median OS was 21.1 months (95% CI 8.2-NR). In the multivariate analysis, the OS was significantly longer in patients with an Eastern Cooperative Oncology Group (ECOG) score of 0, LDH ≤ upper limit of normal, absence of liver metastases and neutrophil-to-lymphocyte ratio (NLR) < 5 (all p ≤ 0.05, log-rank test). These factors allowed the classification of patients into three prognostic risk groups (low/intermediate/high risk) for death.

CONCLUSION

Overall survival of real-world patients from our cohort receiving ipilimumab plus nivolumab was lower than in previous studies. The ECOG score, LDH values, the presence of liver metastases and the NLR were independent prognostic factors for survival.

Immunotherapy of Cancer: Developments and Reference Points, an Unorthodox Approach

Oncology is currently a sector of medical science with accelerated progress due to rapid technological development, the advancement in molecular biology, and the invention of many innovative therapies. Immunotherapy partially accounts for this advance, since it is increasingly playing an important role in the treatment of cancer patients, bringing on a sense of hope and optimism through a series of clinical studies and cases with spectacular results. Immunotherapy, after the initial successes it experienced in the early 20th century, was forgotten after chemotherapy and radiotherapy prevailed and developed slowly in the background. Today, it is the new hope for cancer treatment, despite the unorthodox path it has followed. In this article, we study the course and key points of the discovery of immune-oncology from the oncologist's point of view. We also record the questions that have been posed about immunotherapy that sometimes lead to confusion or stalemate.

Emerging biomarkers for cancer immunotherapy in melanoma

The treatment and prognosis of metastatic melanoma has changed substantially since the advent of novel immune checkpoint inhibitors (ICI), agents that enhance the anti-tumor immune response. Despite the success of these agents, clinically actionable biomarkers to aid patient and regimen selection are lacking. Herein, we summarize and review the evidence for candidate biomarkers of response to ICIs in melanoma. Many of these candidates can be examined as parts of a known molecular pathway of immune response, while others are clinical in nature. Due to the ability of ICIs to illicit dramatic and durable responses, well-validated biomarkers that can be effectively implemented in the clinic will require strong negative predictive values that do not limit patients with who may benefit from ICI therapy.

Future prospects of immune checkpoint blockade in cancer: from response prediction to overcoming resistance

Recent advances in the understating of tumor immunology suggest that cancer immunotherapy is an effective treatment against various types of cancer. In particular, the remarkable successes of immune checkpoint-blocking antibodies in clinical settings have encouraged researchers to focus on developing other various immunologic strategies to combat cancer. However, such immunotherapies still face difficulties in controlling malignancy in many patients due to the heterogeneity of both tumors and individual patients. Here, we discuss how tumor-intrinsic cues, tumor environmental metabolites, and host-derived immune cells might impact the efficacy and resistance often seen during immune checkpoint blockade treatment. Furthermore, we introduce biomarkers identified from human and mouse models that predict clinical benefits for immune checkpoint blockers in cancer.

Reinduction of PD1-inhibitor therapy: first experience in eight patients with metastatic melanoma

Significant progress has been made in the treatment of metastatic melanoma during the last years. Approval of immune-checkpoint inhibitors and targeted therapies has been achieved recently. The sequencing of these therapies is an important issue. Here, we report our experience with the treatment and retreatment with PD1-inhibitors (PD1i) in eight patients. The patients (two female and seven male with a median age of 70 years, all melanoma stage IV, M1c) underwent a first treatment period with PD1i for a median of 5.5 months. Three (37.5%) patients had a stable disease as best response, two (25%) showed progression, two (25%) showed partial response, and one (12.5%) achieved complete remission. PD1i was discontinued due to disease progression in seven patients and due to side effects (pancreatitis) in one patient. Patients were subsequently treated with ipilimumab (n=2), or chemotherapy (n=4), or no other medical treatment (n=2). All eight patients were subsequently retreated with PD1i for a median of 2.5 months. One (12.5%) developed a partial response, whereas in three patients (37.5%) the disease was stabilized. PD1i have shown a high and durable response rate in the first-line treatment of metastatic melanoma. Our study suggests PD1i retreatment as a reasonable option for selected patients. Further investigations are needed to verify the value of PD1i re-exposure and to identify subgroups of patients who can benefit.

Immune checkpoint inhibitors: new strategies to checkmate cancer

Immune checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated protein-4 (CTLA-4) or programmed cell death protein 1 (PD-1) receptors have demonstrated remarkable efficacy in subsets of patients with malignant disease. This emerging treatment modality holds great promise for future cancer treatment and has engaged pharmaceutical research interests in tumour immunology. While ICIs can induce rapid and durable responses in some patients, identifying predictive factors for effective clinical responses has proved challenging. This review summarizes the mechanisms of action of ICIs and outlines important preclinical work that contributed to their development. We explore clinical data that has led to disease-specific drug licensing, and highlight key clinical trials that have revealed ICI efficacy across a range of malignancies. We describe how ICIs have been used as part of combination therapies, and explore their future prospects in this area. We conclude by discussing the incorporation of these new immunotherapeutics into precision approaches to cancer therapy.

Improved survival of patients with melanoma brain metastases in the era of targeted BRAF and immune checkpoint therapies

BACKGROUND

The development of brain metastases is common for systemic treatment failure in patients with melanoma and has been associated with a poor prognosis. Recent advances with BRAF and immune checkpoint therapies have led to improved patient survival. Herein, the authors evaluated the risk of de novo brain metastases and survival among patients with melanoma brain metastases (MBM) since the introduction of more effective therapies.

METHODS

Patients with unresectable AJCC stage III/IV melanoma who received first-line systemic therapy at Moffitt Cancer Center between 2000 and 2012 were identified. Data were collected regarding patient characteristics, stage of disease, systemic therapies, MBM status/management, and overall survival (OS). The risk of de novo MBM was calculated using a generalized estimating equation model and survival comparisons were performed using Kaplan-Meier and Cox proportional analyses.

RESULTS

A total of 610 patients were included, 243 of whom were diagnosed with MBM (40%). Patients with MBM were younger, with a lower frequency of regional metastasis. No significant differences were noted with regard to sex, BRAF status, or therapeutic class. The risk of de novo MBM was found to be similar among patients treated with chemotherapy, biochemotherapy, BRAF-targeted therapy, ipilimumab, and anti-programmed cell death protein 1/programmed death-ligand 1 regimens. The median OS of patients with MBM was significantly shorter when determined from the time of first regional/distant metastasis but not when determined from the time of first systemic therapy. The median OS from the time of MBM diagnosis was 7.5 months, 8.5 months, and 22.7 months, respectively, for patients diagnosed from 2000 to 2008, 2009 to 2010, and 2011 to the time of last follow-up (P = .002).

CONCLUSIONS

Brain metastases remain a common source of systemic treatment failure. The OS for patients with MBM has improved significantly. Further research into MBM prevention is needed. Cancer 2018;124:297-305. © 2017 American Cancer Society.

An Archaeosome-Adjuvanted Vaccine and Checkpoint Inhibitor Therapy Combination Significantly Enhances Protection from Murine Melanoma

Archaeosomes constitute archaeal lipid vesicle vaccine adjuvants that evoke a strong CD8⁺ T cell response to antigenic cargo. Therapeutic treatment of murine B16-ovalbumin (B16-OVA) melanoma with archaeosome-OVA eliminates small subcutaneous solid tumors; however, they eventually resurge despite an increased frequency of circulating and tumor infiltrating OVA-CD8⁺ T cells. Herein, a number of different approaches were evaluated to improve responses, including dose number, interval, and the combination of vaccine with checkpoint inhibitors. Firstly, we found that tumor protection could not be enhanced by repetitive and/or delayed boosting to maximize the CD8⁺ T cell number and/or phenotype. The in vivo cytotoxicity of vaccine-induced OVA-CD8⁺ T cells was impaired in tumor-bearing mice. Additionally, tumor-infiltrating OVA-CD8⁺ T cells had an increased expression of programmed cell death protein-1 (PD-1) compared to other organ compartments, suggesting impaired function. Combination therapy of tumor-bearing mice with the vaccine archaeosome-OVA, and α-CTLA-4 administered concurrently as well as α-PD-1 and an α-PD-L1 antibody administered starting 9 days after tumor challenge given on a Q3Dx4 schedule (days 9, 12, 15 and 18), significantly enhanced survival. Following multi-combination therapy ~70% of mice had rapid tumor recession, with no detectable tumor mass after >80 days in comparison to a median survival of 17-22 days for untreated or experimental groups receiving single therapies. Overall, archaeosomes offer a powerful platform for delivering cancer antigens when used in combination with checkpoint inhibitor immunotherapies.

Combination immunotherapy strategies in advanced non-small cell lung cancer (NSCLC): Does biological rationale meet clinical needs?

Immune checkpoint inhibitors (ICIs) have emerged as one of the main new therapeutic options for advanced non-small cell lung cancer (NSCLC) patients. Even though they demonstrated superiority towards standard chemotherapy in different disease settings, the response rates do not exceed 45% in highly molecularly selected patients. This is related to known limitations of the available biomarkers, as well to the complex and dynamic nature of tumor microenvironment. The study of the different strategies adopted by tumor cells to escape the immune system lays the basis of the new combination strategies. This review focuses on analyzing the biological rationale and early clinical data available concerning therapeutic strategies combining ICIs together, ICIs with different regimens and schedules of standard chemotherapy, ICIs with tyrosine kinase inhibitors, ICIs with antiangiogenic agents and ICs with radiotherapy.

Immunomodulatory effects of current cancer treatment and the consequences for follow-up immunotherapeutics

Recent advances in the use of immunotherapy have led to historic advancements in the field of oncology. Checkpoint inhibitors have demonstrated significant effectiveness against a broadening range of cancers. However, despite the success of antibodies against the immune regulators, CTLA4 and PD-L1/PD-1, only a subset of patients will have a durable response to these therapies, which implies that a broader view of cancer immunity is required. It is becoming increasingly apparent that combination therapy to target multiple events in the cancer-immunity cycle is needed and could potentially extend the benefit of immunotherapy to a larger population. In this review, we discuss the current status of immunotherapy and highlight the use of combination therapy to prime the tumor microenvironment and thereby improve treatment effect.

Delivering safer immunotherapies for cancer

Cancer immunotherapy is now a powerful clinical reality, with a steady progression of new drug approvals and a massive pipeline of additional treatments in clinical and preclinical development. However, modulation of the immune system can be a double-edged sword: Drugs that activate immune effectors are prone to serious non-specific systemic inflammation and autoimmune side effects. Drug delivery technologies have an important role to play in harnessing the power of immune therapeutics while avoiding on-target/off-tumor toxicities. Here we review mechanisms of toxicity for clinically-relevant immunotherapeutics, and discuss approaches based in drug delivery technology to enhance the safety and potency of these treatments. These include strategies to merge drug delivery with adoptive cellular therapies, targeting immunotherapies to tumors or select immune cells, and localizing therapeutics intratumorally. Rational design employing lessons learned from the drug delivery and nanomedicine fields has the potential to facilitate immunotherapy reaching its full potential.

The use of immunotherapy in the treatment of melanoma

Patients with advanced melanoma have a compromised anti-tumor immune response leading to tumor immune tolerance and a tumor microenvironment conducive to disease progression. Immunotherapy that successfully overcomes this tumor-mediated immune suppression has made the greatest impact in the management of this disease over the past few years. This progress through immunotherapy builds upon earlier successes that interferon-α had in the treatment of melanoma in the adjuvant setting, as well as that of high-dose interleukin-2 in advanced melanoma. The development of immune checkpoint inhibitors has led to dramatic clinical activity in advanced melanoma. In particular, anti-CTLA4 and anti-PD1 monoclonal antibodies have taken us forward into the realm of longer survival and durable responses with the possibility of cure in a continuously increasing proportion of patients. Combination immunotherapeutic strategies and novel immunotherapeutic agents are being tested at an accelerated pace where the outlook for long-term survival benefits for the majority of patients appears brighter than ever.

Understanding Immune Checkpoint Inhibitors for Effective Patient Care

BACKGROUND

Immune checkpoint inhibitors represent a paradigm change in the treatment of melanoma and other advanced cancers. These agents manipulate key immune-regulating pathways to restore immune responses against tumors. The success of this approach is demonstrated by ipilimumab (Yervoy®) for the treatment of advanced melanoma, with improvement in three-year survival rates of about 20%. Newer checkpoint inhibitors targeting the programmed death-1 (PD-1) pathway have been approved and may have higher response rates and improved tolerability.

OBJECTIVES

This article aims to educate nurses and increase their comfort level with these new therapies.

METHODS

The mechanism of action of immune checkpoint inhibitors is reviewed, and insight is provided on how nurses can use this knowledge to more effectively care for patients receiving these therapies.

FINDINGS

The use of immuno-oncology agents is increasing. Oncology nurses must understand the basic immune mechanism of action responsible for the novel toxicity profile characterized by immune-related adverse events (irAEs) and clinical response patterns. Managing irAEs with immune checkpoint inhibitors is not necessarily more difficult than with conventional agents, but a difference does exist. Nurses and other healthcare providers must consider the underlying cause of toxicity with immune checkpoint inhibitors when making management decisions.

Immunomodulatory Activity of Nivolumab in Metastatic Renal Cell Carcinoma

PURPOSE

Nivolumab, an anti-PD-1 immune checkpoint inhibitor, improved overall survival versus everolimus in a phase 3 trial of previously treated patients with metastatic renal cell carcinoma (mRCC). We investigated immunomodulatory activity of nivolumab in a hypothesis-generating prospective mRCC trial.

EXPERIMENTAL DESIGN

Nivolumab was administered intravenously every 3 weeks at 0.3, 2, or 10 mg/kg to previously treated patients and 10 mg/kg to treatment-naïve patients with mRCC. Baseline and on-treatment biopsies and blood were obtained. Clinical activity, tumor-associated lymphocytes, PD-L1 expression (Dako immunohistochemistry; ≥5% vs. <5% tumor membrane staining), tumor gene expression (Affymetrix U219), serum chemokines, and safety were assessed.

RESULTS

In 91 treated patients, median overall survival [95% confidence interval (CI)] was 16.4 months [10.1 to not reached (NR)] for nivolumab 0.3 mg/kg, NR for 2 mg/kg, 25.2 months (12.0 to NR) for 10 mg/kg, and NR for treatment-naïve patients. Median percent change from baseline in tumor-associated lymphocytes was 69% (CD3+), 180% (CD4+), and 117% (CD8+). Of 56 baseline biopsies, 32% had ≥5% PD-L1 expression, and there was no consistent change from baseline to on-treatment biopsies. Transcriptional changes in tumors on treatment included upregulation of IFNγ-stimulated genes (e.g., CXCL9). Median increases in chemokine levels from baseline to C2D8 were 101% (CXCL9) and 37% (CXCL10) in peripheral blood. No new safety signals were identified.

CONCLUSIONS

Immunomodulatory effects of PD-1 inhibition were demonstrated through multiple lines of evidence across nivolumab doses. Biomarker changes from baseline reflect nivolumab pharmacodynamics in the tumor microenvironment. These data may inform potential combinations. Clin Cancer Res; 22(22); 5461-71. ©2016 AACR.

Ipilimumab Combined with Nivolumab: A Standard of Care for the Treatment of Advanced Melanoma?

Ipilimumab, an inhibitor of CTLA-4 on T cells, was the first drug to improve overall survival in patients with advanced melanoma. Subsequently, inhibitors of PD-1, including nivolumab and pembrolizumab, were shown to be superior to ipilimumab with a more favorable safety profile. The combination of ipilimumab and nivolumab is associated with a further improvement in response rate and progression-free survival; however, the combination is associated with an increased rate of immune-related toxicities. In 2015, the FDA approved the combination for the treatment of BRAF wild-type advanced melanoma. This review examines the preclinical rationale for the combination of ipilimumab and nivolumab as well as the efficacy and toxicity data from clinical trials in patients with advanced melanoma. Finally, alternative treatment options are discussed with a focus on patient selection. Clin Cancer Res; 22(16); 3992–8. ©2016 AACR.

Burden of Nonsynonymous Mutations among TCGA Cancers and Candidate Immune Checkpoint Inhibitor Responses

Immune checkpoint inhibitor treatment represents a promising approach toward treating cancer and has been shown to be effective in a subset of melanoma, non-small cell lung cancer (NSCLC), and kidney cancers. Recent studies have suggested that the number of nonsynonymous mutations (NsM) can be used to select melanoma and NSCLC patients most likely to benefit from checkpoint inhibitor treatment. It is hypothesized that a higher burden of NsM generates novel epitopes and gene products, detected by the immune system as foreign. We conducted an assessment of NsM across 7,757 tumor samples drawn from 26 cancers sequenced in the Cancer Genome Atlas (TCGA) Project to estimate the subset of cancers (both types and fractions thereof) that fit the profile suggested for melanoma and NSCLC. An additional independent set of 613 tumors drawn from 5 cancers were analyzed for replication. An analysis of the receiver operating characteristic curves of published data on checkpoint inhibitor response in melanoma and NSCLC data estimates a cutoff of 192 NsM with 74% sensitivity and 59.3% specificity to discriminate potential clinical benefit. Across the 7,757 samples of TCGA, 16.2% displayed an NsM count that exceeded the threshold of 192. It is notable that more than 30% of bladder, colon, gastric, and endometrial cancers have NsM counts above 192, which was also confirmed in melanoma and NSCLC. Our data could inform the prioritization of tumor types (and subtypes) for possible clinical trials to investigate further indications for effective use of immune checkpoint inhibitors, particularly in adult cancers. Cancer Res; 76(13); 3767-72. ©2016 AACR.

Harnessing the immune system for the treatment of melanoma: current status and future prospects

When malignant melanoma is diagnosed early, surgical resection is the intervention of choice and is often curative, but many patients present with unresectable disease at later stages. Due to its complex etiology paired with well-documented chemoresistance and high metastatic potential, patients with advanced melanoma had a poor prognosis, and the treatment of this disease remained unsatisfactory for many years. Recently, targeted therapy, immune checkpoint inhibition, or combinatory approaches have revolutionized the therapeutic options of melanoma allowing considerable improvement in disease control and survival. In this review we will summarize these novel therapeutic strategies with particular focus on combinatory immunotherapies and further discuss recent data derived from immunogenomic studies and potential options to improve the therapeutic efficacy of immune modulatory approaches.

Advances in immunotherapy for melanoma

In recent years, the introduction and Federal Drug Administration approval of immune checkpoint inhibitor antibodies has dramatically improved the clinical outcomes for patients with advanced melanoma. These antagonist monoclonal antibodies are capable of unleashing dormant or exhausted antitumor immunity, which has led to durable complete and partial responses in a large number of patients. Ipilimumab targets the cytotoxic T lymphocyte-associated protein 4 (CTLA-4) receptor. Nivolumab and pembrolizumab target programmed cell death protein 1 (PD-1) receptors and have proven to be superior to ipilimumab alone. The combination of ipilimumab and nivolumab has yielded higher response rates, greater tumor shrinkage, and longer progression-free survival than either monotherapy alone. As other promising immunotherapies for melanoma proceed through clinical trials, future goals include defining the role of immune checkpoint inhibitors as adjuvant therapy, identifying optimal combination strategies, and developing reliable predictive biomarkers to guide treatment selection for individual patients.

Adding fuel to the fire: immunogenic intensification

The durable long term clinical benefits seen for certain patients treated with immunotherapy agents has suggested there is significant therapeutic potential to be derived from these agents, as shown by the increasing prominence of this treatment strategy in upcoming clinical trials. There has been a renewed interest and focus on the drivers of tumoral antigen recognition, and the pathways by which various cells of the immune system can stimulate, propagate and execute an effective anti-tumor response. Various challenges lie ahead in the further development of these treatments, including induction of an endogenous anti-tumor response, tumor microenvironment modulation, and T-cell response amplification. Novel treatment combinations may prove of significant added benefit by immunogenic intensification.

Clinical impact of checkpoint inhibitors as novel cancer therapies

Immune responses are tightly regulated via signaling through numerous co-stimulatory and co-inhibitory molecules. Exploitation of these immune checkpoint pathways is one of the mechanisms by which tumors evade and/or escape the immune system. A growing understanding of the biology of immune checkpoints and tumor immunology has led to the development of monoclonal antibodies designed to target co-stimulatory and co-inhibitory molecules in order to re-engage the immune system and restore antitumor immune responses. Anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibodies were among the first to be tested in the clinic, and ipilimumab was the first immune checkpoint inhibitor approved for an anticancer indication. Agents targeting the programmed death 1 (PD-1) pathway, either PD-1 or one of its ligands, programmed death ligand 1, are in active clinical development for numerous cancers, including advanced melanoma and lung cancer. Understanding the different mechanisms of action, safety profiles, and response patterns associated with inhibition of the CTLA-4 and PD-1 pathways may improve patient management as these therapies are moved in to the clinical practice setting and may also provide a rationale for combination therapy with different inhibitors. Additional immune checkpoint molecules with therapeutic potential, including lymphocyte activation gene-3 and glucocorticoid-induced tumor necrosis factor receptor-related gene, also have inhibitors in early stages of clinical development. Clinical responses and safety data reported to date on immune checkpoint inhibitors suggest these agents may have the potential to markedly improve outcomes for patients with cancer.

Impact of NRAS mutations for patients with advanced melanoma treated with immune therapies

Activating NRAS mutations are found in 15% to 20% of melanomas. Immune therapies have become a mainstay in advanced melanoma treatment. We sought to evaluate whether tumor genotype (e.g., NRAS mutations) correlates with benefit from immune therapy in melanoma. We identified 229 patients with melanoma treated with immune therapies [IL2, ipilimumab, or anti-programmed cell death-1/ligand-1 (PD-1/PD-L1)] at three centers and compared clinical outcomes following immune therapy for patients with or without NRAS mutations. Of the 229 patients with melanoma, 60 had NRAS mutation, 53 had BRAF mutation, and 116 had NRAS/BRAF wild type. The NRAS-mutant cohort had superior or a trend to superior outcomes compared with the other cohorts in terms of response to first-line immune therapy (28% vs. 16%, P = 0.04), response to any line of immune therapy (32% vs. 20%, P = 0.07), clinical benefit (response + stable disease lasting ≥ 24 weeks; 50% vs. 31%, P < 0.01), and progression-free survival (median, 4.1 vs. 2.9 months, P = 0.09). Benefit from anti-PD-1/PD-L1 was particularly marked in the NRAS cohort (clinical benefit rate 73% vs. 35%). In an independent group of patient samples, NRAS-mutant melanoma had higher PD-L1 expression (although not statistically significant) compared with other genotypes (8/12 vs. 9/20 samples with ≥ 1% expression; 6/12 vs. 6/20 samples with ≥ 5% expression), suggesting a potential mechanism for the clinical results. This retrospective study suggests that NRAS mutations in advanced melanoma correlate with increased benefit from immune-based therapies compared with other genetic subtypes. If confirmed by prospective studies, this may be explained in part by high rates of PD-L1 expression.

Evolving synergistic combinations of targeted immunotherapies to combat cancer

Immunotherapy has now been clinically validated as an effective treatment for many cancers. There is tremendous potential for synergistic combinations of immunotherapy agents and for combining immunotherapy agents with conventional cancer treatments. Clinical trials combining blockade of cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) may serve as a paradigm to guide future approaches to immuno-oncology combination therapy. In this Review, we discuss progress in the synergistic design of immune-targeting combination therapies and highlight the challenges involved in tailoring such strategies to provide maximal benefit to patients.

Checkpoint blockade for cancer therapy: revitalizing a suppressed immune system

Immune checkpoint receptors are crucial molecules for fine-tuning immune responses. Checkpoint signaling dampens T cell activation to avoid autoimmunity and the destructive effects of an excessive inflammatory response. It is well established that tumors use several mechanisms to avoid elimination by the immune system, and one involves hijacking these checkpoint pathways. Checkpoint blockade therapy utilizes monoclonal antibodies to release the brakes from suppressed T cells, allowing them to be activated and recover their antitumor activity. This therapeutic approach has revolutionized cancer immunotherapy, and extraordinary increases in overall survival were noted, first with anti-CTLA-4 (cytotoxic T lymphocyte-associated protein 4) and subsequently with anti-PD-1 (programmed cell death receptor-1) in melanoma and other malignancies.

The Evolving Role of Immune Checkpoint Inhibitors in Cancer Treatment

Traditional treatment modalities for advanced cancer (radiotherapy, chemotherapy, or targeted agents) act directly on tumors to inhibit or destroy them. Along with surgery, these modalities are predominantly palliative, with toxicity and only modest improvements in survival in patients with advanced solid tumors. Accordingly, long-term survival rates for most patients with advanced cancer remain low, thus there is a need for cancer treatments with favorable benefit and toxicity profiles that can potentially result in long-term survival. The immune system plays a critical role in the recognition and eradication of tumor cells ("immune surveillance"), and immunotherapies based on this concept have been used for decades with some success against a few tumor types; however, most immunotherapies were limited by a lack of either substantial efficacy or specificity, resulting in toxicity. We now have a greater understanding of the complex interactions between the immune system and tumors and have identified key molecules that govern these interactions. This information has revitalized the interest in immunotherapy as an evolving treatment modality using immunotherapeutics designed to overcome the mechanisms exploited by tumors to evade immune destruction. Immunotherapies have potentially complementary mechanisms of action that may allow them to be combined with other immunotherapeutics, chemotherapy, targeted therapy, or other traditional therapies. This review discusses the concepts and data behind immunotherapies, with a focus on the checkpoint inhibitors and their responses, toxicities, and potential for long-term survival, and explores promising single-agent and combination therapies in development.

IMPLICATIONS FOR PRACTICE

Immunotherapy is an evolving treatment approach based on the role of the immune system in eradicating cancer. An example of an immunotherapeutic is ipilimumab, an antibody that blocks cytotoxic T-lymphocyte antigen-4 (CTLA-4) to augment antitumor immune responses. Ipilimumab is approved for advanced melanoma and induced long-term survival in a proportion of patients. The programmed death-1 (PD-1) checkpoint inhibitors are promising immunotherapies with demonstrated sustained antitumor responses in several tumors. Because they harness the patient's own immune system, immunotherapies have the potential to be a powerful weapon against cancer.

Pilot Trial of Selecting Molecularly Guided Therapy for Patients with Non-V600 BRAF-Mutant Metastatic Melanoma: Experience of the SU2C/MRA Melanoma Dream Team

Targeted therapies and immunotherapies have led to significant improvements in the treatment of advanced cancers, including metastatic melanoma. However, new strategies are desperately needed to overcome therapeutic resistance to these agents, as well as to identify effective treatment approaches for cancer patients that fall outside major targetable mutational subtypes (e.g., non-V600 BRAF melanoma). One such strategy is to extend the paradigm of individually tailored, molecularly targeted therapy into a broader spectrum of melanoma patients, particularly those bearing tumors without commonly recognized therapeutic targets, as well as having failed or were ineligible for immunotherapy. In this nontreatment pilot study, next-generation sequencing (NGS) technologies were utilized, including whole genome and whole transcriptome sequencing, to identify molecular aberrations in patients with non-V600 BRAF metastatic melanoma. This information was then rationally matched to an appropriate clinical treatment from a defined pharmacopeia. Five patients with advanced non-V600 BRAF metastatic melanoma were enrolled. We demonstrated successful performance of the following during a clinically relevant time period: patient tumor biopsy, quality DNA/RNA extraction, DNA/RNA-based sequencing for gene expression analysis, analysis utilizing a series of data integration methodologies, report generation, and tumor board review with formulated treatment plan. Streamlining measures were conducted based on the experiences of enrolling, collecting specimens, and analyzing the molecular signatures of patients. We demonstrated the feasibility of using NGS to identify molecular aberrations and generate an individualized treatment plan in this patient population. A randomized treatment study utilizing lessons learned from the conduct of this pilot study is currently underway.

Nivolumab and ipilimumab versus ipilimumab in untreated melanoma

BACKGROUND

In a phase 1 dose-escalation study, combined inhibition of T-cell checkpoint pathways by nivolumab and ipilimumab was associated with a high rate of objective response, including complete responses, among patients with advanced melanoma.

METHODS

In this double-blind study involving 142 patients with metastatic melanoma who had not previously received treatment, we randomly assigned patients in a 2:1 ratio to receive ipilimumab (3 mg per kilogram of body weight) combined with either nivolumab (1 mg per kilogram) or placebo once every 3 weeks for four doses, followed by nivolumab (3 mg per kilogram) or placebo every 2 weeks until the occurrence of disease progression or unacceptable toxic effects. The primary end point was the rate of investigator-assessed, confirmed objective response among patients with BRAF V600 wild-type tumors.

RESULTS

Among patients with BRAF wild-type tumors, the rate of confirmed objective response was 61% (44 of 72 patients) in the group that received both ipilimumab and nivolumab (combination group) versus 11% (4 of 37 patients) in the group that received ipilimumab and placebo (ipilimumab-monotherapy group) (P<0.001), with complete responses reported in 16 patients (22%) in the combination group and no patients in the ipilimumab-monotherapy group. The median duration of response was not reached in either group. The median progression-free survival was not reached with the combination therapy and was 4.4 months with ipilimumab monotherapy (hazard ratio associated with combination therapy as compared with ipilimumab monotherapy for disease progression or death, 0.40; 95% confidence interval, 0.23 to 0.68; P<0.001). Similar results for response rate and progression-free survival were observed in 33 patients with BRAF mutation-positive tumors. Drug-related adverse events of grade 3 or 4 were reported in 54% of the patients who received the combination therapy as compared with 24% of the patients who received ipilimumab monotherapy. Select adverse events with potential immunologic causes were consistent with those in a phase 1 study, and most of these events resolved with immune-modulating medication.

CONCLUSIONS

The objective-response rate and the progression-free survival among patients with advanced melanoma who had not previously received treatment were significantly greater with nivolumab combined with ipilimumab than with ipilimumab monotherapy. Combination therapy had an acceptable safety profile. (Funded by Bristol-Myers Squibb; ClinicalTrials.gov number, NCT01927419.).

Nivolumab in melanoma: latest evidence and clinical potential

Melanoma has historically been considered a refractory disease with few if any options in the advanced/metastatic setting. Advances in both immune and genetically targeted treatment approaches have revolutionized the spectrum of treatment options for melanoma patients over the last several years. Recently, checkpoint inhibition has become a major focus in the immune-based therapy of cancer, especially melanoma. This concept involves inhibition of regulatory cell surface molecules which act normally to dampen or modulate T-cell activation. Cancer, including melanoma, takes advantage of this physiologic mechanism to turn off T-cell activation and prevent effective T-cell antitumor responses. Checkpoint inhibitors such as anti cytotoxic T-lymphocyte antigen 4 (anti-CTLA-4) and anti programmed death-1 (PD-1) can reverse this immune suppression and release T-cell activation. Nivolumab, a monoclonal antibody to the PD-1 receptor, promotes antitumor immunity by removing this key negative regulator of T-cell activation. In phase I/II studies, promising activity and safety have been observed and ongoing phase III trials are comparing nivolumab with other standard of care therapies (chemotherapy, ipilimumab). Efficacy may be even further increased when used in combination with ipilimumab (albeit with increased toxicity). In contrast to typical short-lived responses with cancer therapy in metastatic solid tumors, many responses induced by nivolumab appear durable. In this review, we discuss the evolution of immune therapy in melanoma leading to the development of nivolumab, the clinical experience with this agent, and its future development and clinical potential.

Safety, correlative markers, and clinical results of adjuvant nivolumab in combination with vaccine in resected high-risk metastatic melanoma

PURPOSE

The anti-programmed death-1 (PD-1) antibody nivolumab (BMS-936558) has clinical activity in patients with metastatic melanoma. Nivolumab plus vaccine was investigated as adjuvant therapy in resected stage IIIC and IV melanoma patients.

EXPERIMENTAL DESIGN

HLA-A*0201 positive patients with HMB-45, NY-ESO-1, and/or MART-1 positive resected tumors received nivolumab (1 mg/kg, 3 mg/kg, or 10 mg/kg i.v.) with a multi-peptide vaccine (gp100, MART-1, and NY-ESO-1 with Montanide ISA 51 VG) every 2 weeks for 12 doses followed by nivolumab maintenance every 12 weeks for 8 doses. Primary objective was safety and determination of a maximum tolerated dose (MTD). Secondary objectives included relapse-free survival (RFS), overall survival (OS), and immunologic correlative studies.

RESULTS

Thirty-three patients were enrolled. Median age was 47 years; 55% were male. Two patients had stage IIIC disease; 31 patients had stage IV disease. Median follow-up was 32.1 months. MTD was not reached. Most common related adverse events (>40%) were vaccine injection site reaction, fatigue, rash, pruritus, nausea, and arthralgias. Five related grade 3 adverse events [hypokalemia (1), rash (1), enteritis (1), and colitis (2)] were observed. Ten of 33 patients relapsed. Estimated median RFS was 47.1 months; median OS was not reached. Increases in CTLA-4(+)/CD4(+), CD25(+)Treg/CD4(+), and tetramer specific CD8(+) T-cell populations were observed with treatment (P < 0.05). Trends for lower baseline myeloid-derived suppressor cell and CD25(+)Treg/CD4(+) populations were seen in nonrelapsing patients; PD-L1 tumor status was not significantly associated with RFS.

CONCLUSIONS

Nivolumab with vaccine is well tolerated as adjuvant therapy and demonstrates immunologic activity with promising survival in high-risk resected melanoma, justifying further study.

Immune checkpoint modulation: rational design of combination strategies

Immune recognition and elimination of malignant cells require a series of steps orchestrated by the innate and the adaptive arms of the immune system. The majority of tumors have evolved mechanisms that allow for successful evasion of these immune responses. Recognition of these evasive processes led to the development of immunotherapeutic antibodies targeting the co-stimulatory and co-inhibitory receptors on T cells, with the goal of enhancement of T cell activation or reversal of tumor-induced T cell inhibition. Several of these agents, such as antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1) have already demonstrated significant promise in clinical trials. Clinical benefit of these antibodies as single agents, however, has been limited to a subset of patients and has not been observed in all tumor types. These limitations call for the development of rational combination strategies aiming to extend therapeutic benefit to a broader range of patients. These include: 1) modalities that enhance antigen presentation, such as radiation, cryotherapy, chemotherapy, targeted agents, vaccines, toll-like receptor (TLR) agonists, type I interferon, and oncolytic viruses; 2) additional agents aiming to reverse T cell dysfunction, such as other immune checkpoint inhibitors; and 3) agents targeting other immune inhibitory mechanisms, such as inhibitors of indoleamine dioxygenase (IDO), regulatory T cells, and myeloid-derived suppressor cells (MDSCs). It is becoming increasingly evident that the efficacy of specific combinations will likely not be universal and that the choice of a treatment modality may need to be tailored to fit the needs of each individual patient.

Anti-programmed death receptor 1 immunotherapy in melanoma: rationale, evidence and clinical potential

Malignant melanoma is a significant public health problem; according to 2013 Surveillance, Epidemiology, and End Results data, its average incidence rate rose 2.6% each year for the last decade, and it is now the fifth most common cancer diagnosis in the United States. The rising incidence and historical poor response to chemotherapy have led to intense investigation of novel treatments for melanoma, including therapies to improve the immune-mediated destruction of cancer cells. Among the hallmarks of malignancy is the ability to evade this process: while early stages of tumor growth can induce functional CD8+ T-cell responses, cancer cells become increasingly embedded in an immune-suppressive tumor stroma. In the tumor microenvironment, T-cell proliferation and effector function are impaired due to engagement of T-cell programmed death receptor 1 (PD-1) with programmed death receptor ligand (PD-L1) expressed by cancer cells and antigen-presenting cells, which blocks T-cell-mediated cytotoxicity. This receptor-ligand engagement thereby inhibits immunity, allows the tumor to continue to grow, and contributes to the phenomenon of 'T-cell exhaustion'. One immunotherapy strategy currently under investigation is inhibition of the interaction between PD-L1 and PD-1, thereby overcoming a critical immune checkpoint to facilitate destruction of cancer cells. In this review we discuss the preclinical rationale for PD-1 pathway inhibition in cancer, recent results of clinical trials targeting PD-1 and PD-L1, and evaluate its potential as a future anticancer therapy.

Ipilimumab in the treatment of advanced melanoma - a clinical update

INTRODUCTION

Ipilimumab has become an important treatment option for patients with advanced melanoma; however, active research perseveres to resolve many clinical practice issues and to further improve the therapeutic index of this agent.

AREAS COVERED

This article aims to provide an update on long-term data, current challenge and recent progress relating to the clinical application of ipilimumab in the treatment of advanced melanoma. A literature search using PubMed database was conducted using search words ipilimumab, melanoma, treatment sequencing, adjuvant therapy, combination therapy, and biomarkers. Data were also obtained from meeting abstracts and clinical trial registries.

EXPERT OPINION

Signal of clinical activity as adjuvant therapy in patients with resected high-risk melanoma begins to emerge, but longer follow-up is required for confirmation. Many issues, such as optimal dosing schedules and therapeutic sequences, remain unraveled. At present, treatment should be individualized based on patient- and disease-specific factors. Immunotherapy like ipilimumab still represents the best treatment option for durable remission; however, targeted therapies are more appropriate for patients with BRAF V600-mutated tumor who are symptomatic or have rapidly growing disease. With novel therapeutic options in the pipeline, the role of ipilimumab continues to evolve in the rapidly changing treatment landscape of advanced melanoma. Most likely, this agent will be utilized in combinatorial or sequential approach.

Therapeutic uses of anti-PD-1 and anti-PD-L1 antibodies

Despite extensive investigation over the past three decades, cancer immunotherapy has produced limited success, with few agents achieving approval by the Food and Drug Administration and even the most effective helping only a minority of patients, primarily with melanoma or renal cancer. In recent years, immune checkpoints that maintain physiologic self-tolerance have been implicated in the down-regulation of anti-tumor immunity. Efforts to restore latent anti-tumor immunity have focused on antibody-based interventions targeting CTL antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) on T lymphocytes and its principal ligand (PD-L1) on tumor cells. Ipilimumab, an antibody targeting CTLA-4, appears to restore tumor immunity at the priming phase, whereas anti-PD-1/PD-L1 antibodies restore immune function in the tumor microenvironment. Although ipilimumab can produce durable long-term responses in patients with advanced melanoma, it is associated with significant immune-related toxicities. By contrast, antibodies targeting either PD-1 or PD-L1 have produced significant anti-tumor activity with considerably less toxicity. Activity was seen in patients with melanoma and renal cancer, as well as those with non-small-cell lung, bladder and head and neck cancers, tumors not previously felt to be sensitive to immunotherapy. The tolerability of PD-1-pathway blockers and their unique mechanism of action have made them ideal backbones for combination regimen development. Combination approaches involving cytotoxic chemotherapy, anti-angiogenic agents, alternative immune-checkpoint inhibitors, immunostimulatory cytokines and cancer vaccines are currently under clinical investigation. Current efforts focus on registration trials of single agents and combinations in various diseases and disease settings and identifying predictive biomarkers of response.