Development of Ipilimumab: Contribution to a New Paradigm for Cancer Immunotherapy

Novel cancer therapies: treatments driven by tumour biology

The traditional view is that treatments within oncology largely consist of chemotherapy, which aims to maximise damage to the rapidly dividing cancer cells but often at the expense of normal cells and overall quality of life for the patient. The development of anticancer drugs has changed from the serendipitous discoveries of the past, to today's purposeful targeting of cancer cells which takes advantage of novel technological developments and a greater understanding of tumour biology. The aim of these new treatments is to affect the essential function of the cancer cell while sparing normal cells, and limiting side effects. The phenotypic characteristics of tumours, such as unregulated growth signalling, development of new vascular systems and the evasion of immune destruction are used to identify potential drug targets. Here we review the clinical evidence and molecular mechanisms for novel therapies that are currently in use and those that are in development.

Use of ERC-1671 Vaccine in a Patient with Recurrent Glioblastoma Multiforme after Progression during Bevacizumab Therapy: First Published Report

Glioblastoma multiforme is a highy aggressive tumor that recurs despite resection, focal beam radiation, and temozolamide chemotherapy. ERC-1671 is an experimental treatment strategy that uses the patient's own immune system to attack the tumor cells. The authors report preliminary data on the first human administration of ERC-1671 vaccination under a single-patient, compassionate-use protocol. The patient survived for ten months after the vaccine administration without any other adjuvant therapy and died of complications related to his previous chemotherapies.

PD-1 pathway inhibitors: the next generation of immunotherapy for advanced melanoma

Checkpoint inhibitors are revolutionizing treatment options and expectations for patients with melanoma. Ipilimumab, a monoclonal antibody against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), was the first approved checkpoint inhibitor. Emerging long-term data indicate that approximately 20% of ipilimumab-treated patients achieve long-term survival. The first programmed death 1 (PD-1) inhibitor, pembrolizumab, was recently approved by the United States Food and Drug Administration for the treatment of melanoma; nivolumab was previously approved in Japan. PD-1 inhibitors are also poised to become standard of care treatment for other cancers, including non-small cell lung cancer, renal cell carcinoma and Hodgkin's lymphoma. Immunotherapy using checkpoint inhibition is a different treatment approach to chemotherapy and targeted agents: instead of directly acting on the tumor to induce tumor cell death, checkpoint inhibitors enhance or de novo stimulate antitumor immune responses to eliminate cancer cells. Initial data suggest that objective anti-tumor response rates may be higher with anti-PD-1 agents compared with ipilimumab and the safety profile may be more tolerable. This review explores the development and next steps for PD-1 pathway inhibitors, including discussion of their novel mechanism of action and clinical data to-date, with a focus on melanoma.

Five-year survival rates for treatment-naive patients with advanced melanoma who received ipilimumab plus dacarbazine in a phase III trial

PURPOSE

There is evidence from nonrandomized studies that a proportion of ipilimumab-treated patients with advanced melanoma experience long-term survival. To demonstrate a long-term survival benefit with ipilimumab, we evaluated the 5-year survival rates of patients treated in a randomized, controlled phase III trial.

PATIENTS AND METHODS

A milestone survival analysis was conducted to capture the 5-year survival rate of treatment-naive patients with advanced melanoma who received ipilimumab in a phase III trial. Patients were randomly assigned 1:1 to receive ipilimumab at 10 mg/kg plus dacarbazine (n = 250) or placebo plus dacarbazine (n = 252) at weeks 1, 4, 7, and 10 followed by dacarbazine alone every 3 weeks through week 22. Eligible patients could receive maintenance ipilimumab or placebo every 12 weeks beginning at week 24. A safety analysis was conducted on patients who survived at least 5 years and continued to receive ipilimumab as maintenance therapy.

RESULTS

The 5-year survival rate was 18.2% (95% CI, 13.6% to 23.4%) for patients treated with ipilimumab plus dacarbazine versus 8.8% (95% CI, 5.7% to 12.8%) for patients treated with placebo plus dacarbazine (P = .002). A plateau in the survival curve began at approximately 3 years. In patients who survived at least 5 years and continued to receive ipilimumab, grade 3 or 4 immune-related adverse events were observed exclusively in the skin.

CONCLUSION

The additional survival benefit of ipilimumab plus dacarbazine is maintained with twice as many patients alive at 5 years compared with those who initially received placebo plus dacarbazine. These results demonstrate a durable survival benefit with ipilimumab in advanced melanoma.

The ipilimumab lesson in melanoma: achieving long-term survival

The anti-cytotoxic T-lymphocyte antigen-4 (anti-CTLA-4) antibody ipilimumab is the first treatment that significantly improved the survival rates of metastatic melanoma patients, marking a new era in the treatment of melanoma. During its development, a hallmark of ipilimumab therapy was the extended duration of response, achieved in 20% of patients. The follow-up of patients included in phase II and phase III trials and in expanded access programs revealed that the survival rates remained stable after 3 years. These results demonstrated that ipilimumab induces an effective anti-tumor immune response persisting after the completion of treatment, and suggested a potential remission in a subset of patients. In this article we review the development of ipilimumab and highlight the long-term results. This approach emphasizes the need to optimize the use of ipilimumab in the future, by identifying the patients most likely to achieve long term survival after ipilimumab therapy, and by developing combined therapeutic approaches involving cytotoxic agents, targeted therapies or other immunotherapies to achieve durable control in a larger proportion of patients.

Pooled Analysis of Long-Term Survival Data From Phase II and Phase III Trials of Ipilimumab in Unresectable or Metastatic Melanoma

PURPOSE

To provide a more precise estimate of long-term survival observed for ipilimumab-treated patients with advanced melanoma, we performed a pooled analysis of overall survival (OS) data from multiple studies.

METHODS

The primary analysis pooled OS data for 1,861 patients from 10 prospective and two retrospective studies of ipilimumab, including two phase III trials. Patients were previously treated (n = 1,257) or treatment naive (n = 604), and the majority of patients received ipilimumab 3 mg/kg (n = 965) or 10 mg/kg (n = 706). We also conducted a secondary analysis of OS data (n = 4,846) with an additional 2,985 patients from an expanded access program. OS rates were estimated using the Kaplan-Meier method.

RESULTS

Among 1,861 patients, median OS was 11.4 months (95% CI, 10.7 to 12.1 months), which included 254 patients with at least 3 years of survival follow-up. The survival curve began to plateau around year 3, with follow-up of up to 10 years. Three-year survival rates were 22%, 26%, and 20% for all patients, treatment-naive patients, and previously treated patients, respectively. Including data from the expanded access program, median OS was 9.5 months (95% CI, 9.0 to 10.0 months), with a plateau at 21% in the survival curve beginning around year 3.

CONCLUSION

To our knowledge, this is the largest analysis of OS to date for ipilimumab-treated patients with advanced melanoma. We observed a plateau in the survival curve, beginning at approximately 3 years, which was independent of prior therapy or ipilimumab dose. These data add to the evidence supporting the durability of long-term survival in ipilimumab-treated patients with advanced melanoma.

CTLA-4 blockade with ipilimumab: biology, safety, efficacy, and future considerations

Melanoma remains a critical public health problem worldwide. Patients with stage IV disease have very poor prognosis and their 1-year survival rate is only 25%. Until recently, systemic treatments with a positive impact on overall survival (OS) had remained elusive. In recent years, the United States Food and Drug Administration (FDA) – approved several novel agents targeting the RAS/RAF/MEK/ERK pathway (vemurafenib, dabrafenib, and trametinib) – critical in cell division and proliferation of melanoma, and an immune checkpoint inhibitor (ipilimumab) directed against the cytotoxic T lymphocyte Antigen - (CTLA-4). Moreover, recent reports of clinical trials studying other immune checkpoint modulating agents will most likely result in their FDA approval within the next months. This review focuses on ipilimumab, its safety and efficacy, and future considerations. Ipilimumab has demonstrated a positive OS impact after a several-year follow-up. It is also recognized that due to its mechanism of action, the response patterns to ipilimumab can differ from those observed in patients following treatment with conventional cytotoxic agents and even the most recently approved BRAF inhibitors. Most patients (84.8%) experience drug-related adverse events (AEs) of any grade; most of these are mild to moderate and immune mediated. However, a minority of patients may also experience severe and life-threatening AEs. In clinical studies, AEs were managed according to guidelines that emphasized close clinical monitoring and early use of corticosteroids when appropriate. Preliminary results have taught us the potential greater toxicity when in combination with vemurafenib, and the greater antitumor efficacy when combined with nivolumab, a monoclonal antibody directed against programmed death receptor-1 (PD-1), another immune checkpoint inhibitor. Future challenges include the optimization of dosing and toxicities when used as a single agent, and studying the safety and efficacy of combinations with targeted small molecules and other monoclonal antibodies to treat patients with melanoma and other malignancies.

The development of immunomodulatory monoclonal antibodies as a new therapeutic modality for cancer: the Bristol-Myers Squibb experience

The discovery and increased understanding of the complex interactions regulating the immune system have contributed to the pharmacologic activation of antitumor immunity. The activity of effector cells, such as T and NK cells, is regulated by an array of activating and attenuating receptors and ligands. Agents that target these molecules can modulate immune responses by exerting antagonistic or agonistic effects. Several T- or NK-cell modulators have entered clinical trials, and two have been approved for use. Ipilimumab (Yervoy®, Bristol-Myers Squibb) and nivolumab (OPDIVO, Ono Pharmaceutical Co., Ltd./Bristol-Myers Squibb) were approved for the treatment of metastatic melanoma, in March 2011 in the United States, and in July 2014 in Japan, respectively. The clinical activity of these two antibodies has not been limited to tumor types considered sensitive to immunotherapy, and promising activity has been reported in other solid and hematologic tumors. Clinical development of ipilimumab and nivolumab has presented unique challenges in terms of safety and efficacy, requiring the establishment of new evaluation criteria for adverse events and antitumor effects. Guidelines intended to help oncologists properly manage treatment in view of these non-traditional features have been implemented. The introduction of this new modality of cancer treatment, which is meant to integrate with or replace the current standards of care, requires additional efforts in terms of optimization of treatment administration, identification of biomarkers and application of new clinical trial designs. The availability of immune modulators with different mechanisms of action offers the opportunity to establish immunological combinations as new standards of care.

Successful treatment with Ipilimumab and Interleukin-2 in two patients with metastatic melanoma and systemic autoimmune disease

Two patients were treated with immunotherapy for metastatic malignant melanoma (MM) despite suffering from systemic autoimmune disease, i.e., ulcerative colitis (UC) and Behcets disease (BD), respectively. Both patients benefitted from the treatment. The patient with UC achieved partial remission of all measurable parameters after treatment with Ipilimumab, while the patient with BD achieved a complete remission of MM after treatment with Interleukin-2 (IL-2) and Interferon-α (IFN-α). Moreover, no aggravation of symptoms related to the autoimmune diseases was seen during treatment, in contrast, clinical indications of improvement were observed. These two cases illustrate that the presence of autoimmune disease does not necessarily predict increased autoimmune toxicity in connection with immunotherapy. They also raise the question of whether autoimmune disease should continue to be an absolute exclusion criterion for treatment of MM with immunotherapy. Consequently, given the poor prognosis of refractory MM, immunotherapies need to be taken into consideration even in cases of autoimmune comorbidity due to the potential long-term benefit that these therapies offer to MM patients.

Metastatic castration-resistant prostate cancer: new therapies, novel combination strategies and implications for immunotherapy

For the past decade, docetaxel has remained the global standard of care for frontline treatment of metastatic castration-resistant prostate cancer (mCRPC). Until recently, there were limited options for patients with mCRPC following docetaxel failure or resistance, but now the approved treatment choices for these patients have expanded to include abiraterone acetate, cabazitaxel and enzalutamide. Additionally, the radioactive therapeutic agent radium-223 dichloride has been recently approved in patients with CRPC with bone metastases. Although each of these agents has been shown to convey significant survival benefit as a monotherapy, preclinical findings suggest that combining such innovative strategies with traditional treatments may achieve additive or synergistic effects, further augmenting patient benefit. This review will discuss the transformation of the post-docetaxel space in mCRPC, highlighting the spectrum of newly approved agents in this setting in the USA and the European Union, as well as summarizing treatments with non-chemotherapeutic mechanisms of action that have demonstrated promising results in recent phase 3 trials. Lastly, this review will address the potential of combinatorial regimens in mCRPC, including the pairing of novel immunotherapeutic approaches with chemotherapy, radiotherapy or androgen ablation.

Survival follow-up and ipilimumab retreatment of patients with advanced melanoma who received ipilimumab in prior phase II studies

BACKGROUND

This report provides a survival update at a follow-up of >5 years (5.5-6 years) for patients with advanced melanoma who previously received ipilimumab in phase II clinical trials. Safety and efficacy data following ipilimumab retreatment are also reported.

PATIENTS AND METHODS

Patients who previously received ipilimumab 0.3, 3, or 10 mg/kg in one of six phase II trials (CA184-004, CA184-007, CA184-008, CA184-022, MDX010-08, and MDX010-15) were eligible to enroll in the companion study, CA184-025. Upon enrollment, patients initially received ipilimumab retreatment, extended maintenance therapy, or were followed for survival only. Overall survival (OS) rates were evaluated in patients from studies CA184-004, CA184-007, CA184-008, and CA184-022. Safety and best overall response during ipilimumab retreatment at 10 mg/kg were assessed in study CA184-025.

RESULTS

Five-year OS rates for previously treated patients who received ipilimumab induction at 0.3, 3, or 10 mg/kg were 12.3%, 12.3%-16.5%, and 15.5%-28.4%, respectively. Five-year OS rates for treatment-naive patients who received ipilimumab induction at 3 or 10 mg/kg were 26.8% and 21.4%-49.5%, respectively. Little to no change in OS was observed from year 5 up to year 6. The objective response rate among retreated patients was 23%. Grade 3/4 immune-related adverse events occurred in 25%, 5.9%, and 13.2% of retreated patients who initially received ipilimumab 0.3, 3, and 10 mg/kg, with the most common being observed in the skin (4.2%, 2.9%, 3.8%) and gastrointestinal tract (12.5%, 2.9%, 3.8%), respectively.

CONCLUSIONS

At a follow-up of 5-6 years, ipilimumab continues to demonstrate durable, long-term survival in a proportion of patients with advanced melanoma. In some patients, ipilimumab retreatment can re-establish disease control with a safety profile that is comparable with that observed during ipilimumab induction. Further studies are needed to determine the contribution of ipilimumab retreatment to OS.

CLINICALTRIALSGOV

NCT00162123.

Therapeutic use of anti-CTLA-4 antibodies

Targeting CTLA-4 represents a new type of immunotherapeutic approach, namely immune checkpoint inhibition. Blockade of CTLA-4 by ipilimumab was the first strategy to achieve a significant clinical benefit for late-stage melanoma patients in two phase 3 trials. These results fueled the notion of immunotherapy being the breakthrough strategy for oncology in 2013. Subsequently, many trials have been set up to test various immune checkpoint modulators in malignancies, not only in melanoma. In this review, recent new ideas about the mechanism of action of CTLA-4 blockade, its current and future therapeutic use, and the intensive search for biomarkers for response will be discussed. Immune checkpoint blockade, targeting CTLA-4 and/or PD-1/PD-L1, is currently the most promising systemic therapeutic approach to achieve long-lasting responses or even cure in many types of cancer, not just in patients with melanoma.

Clinical evaluation of compounds targeting PD-1/PD-L1 pathway for cancer immunotherapy

Significant enthusiasm currently exists for new immunotherapeutic strategies: blocking the interaction between programmed death-1 receptor on T-cells and programmed death-ligand 1 on tumor cells to boost immune system stimulation to fight cancer. Immunomodulation with the antiprogrammed death-1/programmed death-ligand 1 monoclonal antibodies has shown to mediate tumor shrinkage and extend overall survival from several pivotal phase I/II studies in melanoma, renal cell carcinoma, and non-small cell lung cancer. This has prompted multiple large ongoing phase III trials with the expectation for fast-track FDA approvals to satisfy unmet medical needs. Compounds targeting the programmed death-1 pathway that are in clinical trials fall into two major categories, namely antiprogrammed death-1 antibodies: Nivolumab, MK-3475, and pidilizumab; and antiprogrammed death-ligand 1 antibodies: MPDL3280A, BMS-936559, MEDI4736, and MSB0010718C. We reviewed the clinical efficacy and safety of each compound based upon major registered clinical trials and published clinical data. Overall, response rate of more than 20% is consistently seen across all these trials, with maximal response of approximately 50% achieved by certain single antiprogrammed death-1 agents or when used in combination with cytotoxic T-lymphocyte antigen-4 blockade. The responses seen are early, durable, and have continued after treatment discontinuation. Immune-related adverse events are the most common side effects seen in these clinical trials. Overall, the skin and gastrointestinal tract are the most common organ systems affected by these compounds while hepatic, endocrine, and neurologic events are less frequent. These side effects are low grade, manageable, and typically resolve within a relatively short time frame with a predictable resolution pattern given proper management. We therefore propose detailed guidelines for management of major immune-related adverse events that are anticipated with antiprogrammed death-1/programmed death-ligand 1 therapies based on general experience with other monoclonal antibodies and the established management algorithms for immune-related adverse events for cytotoxic T-lymphocyte antigen-4 blockade with ipilimumab. We anticipate that the antiprogrammed death-1 strategy will become a viable and crucial clinical strategy for cancer therapy.

Immunogenicity of murine solid tumor models as a defining feature of in vivo behavior and response to immunotherapy

Immune profiling has been widely used to probe mechanisms of immune escape in cancer and identify novel targets for therapy. Two emerging uses of immune signatures are to identify likely responders to immunotherapy regimens among individuals with cancer and to understand the variable responses seen among subjects with cancer in immunotherapy trials. Here, the immune profiles of 6 murine solid tumor models (CT26, 4T1, MAD109, RENCA, LLC, and B16) were correlated to tumor regression and survival in response to 2 immunotherapy regimens. Comprehensive profiles for each model were generated using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and flow cytometry techniques, as well as functional studies of suppressor cell populations (regulatory T cells and myeloid-derived suppressor cells), to analyze intratumoral and draining lymphoid tissues. Tumors were stratified as highly or poorly immunogenic, with highly immunogenic tumors showing a significantly greater presence of T-cell costimulatory molecules and immune suppression in the tumor microenvironment. An absence of tumor-infiltrating cytotoxic T lymphocytes and mature dendritic cells was seen across all models. Delayed tumor growth and increased survival with suppressor cell inhibition and tumor-targeted chemokine+/-dendritic cells vaccine immunotherapy were associated with high tumor immunogenicity in these models. Tumor MHC class I expression correlated with the overall tumor immunogenicity level and was a singular marker to predict immunotherapy response with these regimens. By using experimental tumor models as surrogates for human cancers, these studies demonstrate how select features of an immune profile may be utilized to identify patients most likely to respond to immunotherapy regimens.

Clinical experience with ipilimumab 3 mg/kg: real-world efficacy and safety data from an expanded access programme cohort

BACKGROUND

Ipilimumab improves survival in patients with advanced melanoma. The activity and safety of ipilimumab outside of a clinical trial was assessed in an expanded access programme (EAP).

METHODS

Ipilimumab was available upon physician request for patients aged 16 or over with pretreated stage III (unresectable)/IV melanoma, for whom no other therapeutic option was available. Patients received ipilimumab 3 mg/kg every 3 weeks for four doses. Patients with stable disease or an objective response to ipilimumab were eligible for retreatment upon disease progression. Tumour assessments were conducted at baseline and week 12. Patients were monitored for adverse events (AEs) within 3 to 4 days of each scheduled visit.

RESULTS

Of 855 patients participating in the EAP in Italy, 833 were evaluable for response. Of these, 13% had an objective immune response, and the immune-related disease control rate was 34%. Median progression-free survival and overall survival were 3.7 and 7.2 months, respectively. Efficacy was independent of BRAF and NRAS mutational status. Overall, 33% of patients reported an immune-related AE (irAE). The frequency of irAEs was not associated with response to ipilimumab.

CONCLUSIONS

Outside of a clinical trial setting, ipilimumab is a feasible treatment option in patients with pretreated metastatic melanoma, regardless of BRAF and NRAS mutational status. Data from this large cohort of patients support clinical trial evidence that ipilimumab can induce durable disease control and long-term survival in patients who have failed to respond to prior treatment.

Efficacy and safety of ipilimumab in patients with advanced melanoma and brain metastases

Patients with melanoma brain metastases have a poor prognosis and historically have been excluded from clinical trials. The Expanded Access Program (EAP) provided an opportunity to evaluate the feasibility of ipilimumab (3 mg/kg every 3 weeks for four doses) in patients with stage 3 (unresectable) or 4 melanoma and asymptomatic brain metastases, who had failed or did not tolerate previous treatments and had no other therapeutic option available. Tumor assessments were conducted at baseline and week 12 using immune-related response criteria and patients were monitored for adverse events (AEs). Of 855 patients participating in the EAP in Italy, 146 had asymptomatic brain metastases. With a median follow-up of 4 months, the global disease control rate was 27%, including 4 patients with a complete response and 13 with a partial response. Median progression-free survival and overall survival were 2.8 and 4.3 months, respectively and approximately one-fifth of patients were alive 1 year after starting ipilimumab. In total, 29% of patients reported a treatment-related AE of any grade, which were grade 3/4 in 6% of patients. AEs were generally reversible with treatment as per protocol-specific guidelines. Ipilimumab shows durable benefits in some patients with advanced melanoma metastatic to the brain, with safety results consistent with those previously reported in clinical trials.

Ipilimumab in patients with cancer and the management of dermatologic adverse events

Ipilimumab is a fully human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen-4 to augment antitumor T-cell responses. Phase III studies have demonstrated survival benefit in both previously treated and treatment-naïve patients with metastatic melanoma. In clinical trials, adverse events (AEs) related to treatment with ipilimumab were mostly grade 1/2 (as per Common Terminology Criteria for AEs, Version 4.02), and mostly reversible with appropriate management. Distinct immune-related AEs that may reflect the mechanism of action of ipilimumab have been identified, and occur commonly in the skin, typically presenting as a maculopapular rash, which can be accompanied by pruritus, pruritus with no skin lesions, alopecia, and vitiligo. Histologic analyses have revealed epidermal spongiosis, and perivascular CD4(+) T-cell infiltrates with some eosinophils in areas of rash. Timely implementation of toxicity-specific treatment guidelines that emphasize vigilance and early intervention allows mitigation of dermatologic AEs. Adherence to guidelines is necessary to maintain quality of life, ensure consistent dosing, and obtain the best possible clinical outcome.

VISTA Regulates the Development of Protective Antitumor Immunity

V-domain Ig suppressor of T-cell activation (VISTA) is a novel negative checkpoint ligand that is homologous to PD-L1 and suppresses T-cell activation. This study demonstrates the multiple mechanisms whereby VISTA relieves negative regulation by hematopoietic cells and enhances protective antitumor immunity. VISTA is highly expressed on myeloid cells and Foxp3(+)CD4(+) regulatory cells, but not on tumor cells within the tumor microenvironment (TME). VISTA monoclonal antibody (mAb) treatment increased the number of tumor-specific T cells in the periphery and enhanced the infiltration, proliferation, and effector function of tumor-reactive T cells within the TME. VISTA blockade altered the suppressive feature of the TME by decreasing the presence of monocytic myeloid-derived suppressor cells and increasing the presence of activated dendritic cells within the tumor microenvironment. In addition, VISTA blockade impaired the suppressive function and reduced the emergence of tumor-specific Foxp3(+)CD4(+) regulatory T cells. Consequently, VISTA mAb administration as a monotherapy significantly suppressed the growth of both transplantable and inducible melanoma. Initial studies explored a combinatorial regimen using VISTA blockade and a peptide-based cancer vaccine with TLR agonists as adjuvants. VISTA blockade synergized with the vaccine to effectively impair the growth of established tumors. Our study therefore establishes a foundation for designing VISTA-targeted approaches either as a monotherapy or in combination with additional immune-targeted strategies for cancer immunotherapy.

VISTA is an immune checkpoint molecule for human T cells

V-domain Ig suppressor of T cell activation (VISTA) is a potent negative regulator of T-cell function that is expressed on hematopoietic cells. VISTA levels are heightened within the tumor microenvironment, in which its blockade can enhance antitumor immune responses in mice. In humans, blockade of the related programmed cell death 1 (PD-1) pathway has shown great potential in clinical immunotherapy trials. Here, we report the structure of human VISTA and examine its function in lymphocyte negative regulation in cancer. VISTA is expressed predominantly within the hematopoietic compartment with highest expression within the myeloid lineage. VISTA-Ig suppressed proliferation of T cells but not B cells and blunted the production of T-cell cytokines and activation markers. Our results establish VISTA as a negative checkpoint regulator that suppresses T-cell activation, induces Foxp3 expression, and is highly expressed within the tumor microenvironment. By analogy to PD-1 and PD-L1 blockade, VISTA blockade may offer an immunotherapeutic strategy for human cancer.

Ipilimumab retreatment in patients with pretreated advanced melanoma: the expanded access programme in Italy

BACKGROUND

Retreatment with ipilimumab has been shown to re-establish disease control in some patients with disease progression. Here, we report the efficacy and safety of retreatment with ipilimumab 3 mg kg(-1) among patients participating in an expanded access programme in Italy.

METHODS

Patients who achieved disease control during induction therapy were retreated with ipilimumab upon progression (3 mg kg(-1) every 3 weeks for up to four doses), providing they had not experienced toxicity that precluded further dosing. Tumour assessments were conducted after retreatment, and patients were monitored throughout for adverse events.

RESULTS

Of 855 patients treated with ipilimumab, 51 were retreated upon disease progression. Of these, 28 (55%) regained disease control upon retreatment and 42% were alive 2 years after the first induction dose of ipilimumab; median overall survival was 21 months. Eleven patients (22%) had a treatment-related adverse event of any grade during retreatment. These were generally mild-to-moderate and resolved within a median of 4 days. No new types of toxicity were reported.

CONCLUSIONS

For patients who meet predefined criteria, retreatment with ipilimumab is generally well tolerated and can translate into clinical benefit. This strategy should be compared with other therapeutic options in randomised controlled trials.

Immune checkpoint blockade in cancer treatment: a double-edged sword cross-targeting the host as an "innocent bystander"

Targeted immune checkpoint blockade augments anti-tumor immunity and induces durable responses in patients with melanoma and other solid tumors. It also induces specific “immune-related adverse events” (irAEs). IrAEs mainly include gastrointestinal, dermatological, hepatic and endocrinological toxicities. Off-target effects that arise appear to account for much of the toxicity of the immune checkpoint blockade. These unique “innocent bystander” effects are likely a direct result of breaking immune tolerance upon immune check point blockade and require specific treatment guidelines that include symptomatic therapies or systemic corticosteroids. What do we need going forward to limit immune checkpoint blockade-induced toxicity? Most importantly, we need a better understanding of the roles played by these agents in normal tissues, so that we can begin to predict potentially problematic side effects on the basis of their selectivity profile. Second, we need to focus on the predictive factors of the response and toxicity of the host rather than serially focusing on individual agents. Third, rigorous biomarker-driven clinical trials are needed to further elucidate the mechanisms of both the benefit and toxicity. We will summarize the double-edged sword effect of immunotherapeutics in cancer treatment.

Orchestrating immune check-point blockade for cancer immunotherapy in combinations

Inhibitory receptors on immune system cells respond to membrane-bound and soluble ligands to abort or mitigate the intensity of immune responses by raising thresholds of activation, halting proliferation, favoring apoptosis or inhibiting/deviating effector function differentiation. Such evolutionarily selected inhibitory mechanisms are termed check-points and therefore check-point inhibitors empower any ongoing anti-cancer immune response that might have been too weak or exhausted. Monoclonal antibodies (mAb) interfering with CTLA-4-CD80/86, PD-1 - PD-L1, TIM-3-GAL9 and LAG3-MHC-II belong to this category of check-point inhibitors. The anti-CTLA-4 mAb ipilimumab has been approved for metastatic melanoma. Anti-PD-1 and anti-PD-L1 mAbs have shown extremely encouraging clinical activity. The potential of combination strategies with these agents has recently been highlighted by clinical observations on CTLA-4+PD-1 combined blockade in melanoma patients.

Real-world impact of education: treating patients with ipilimumab in a community practice setting

After decades without promising new treatments for advanced and metastatic melanoma, ipilimumab was the first systemic therapy approved for use in this patient population. A fully human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen 4 (CTLA-4) to augment antitumor T-cell responses, ipilimumab significantly extended overall survival in clinical trials. Because ipilimumab is associated with a set of immune-related adverse events that likely reflect the agent's mechanism of action, a management guide has been established. Nurses play a significant role in initially identifying these adverse reactions and assisting in patient education, treatment, and follow-up. Herein, we discuss commonly asked questions related to ipilimumab therapy and treatment of adverse events, and how nurses can be prepared to answer these questions as they arise from patients and caregivers.

Immunotherapy treatments for small-cell lung cancer: past, present and future

Small-cell lung cancer remains a considerable cause of morbidity and mortality. To this day, first-line therapy continues to be a platinum agent with etoposide, combined with radiation therapy in cases of limited stage disease. Numerous, largely unsuccessful, attempts at controlling the disease have included different chemotherapy strategies, the utilization of antiangiogenic agents, tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors and other treatment modalities. Immunotherapy, including vaccines, immune response modifiers, inhibitors of check point blockades and immunologic-targeted toxins may well be the future of treatment, not only to enhance the proven chemotherapy effects, but to improve the control of minimal residual disease and the response with salvage chemotherapy. This article reviews the current advances in immunotherapeutic strategies against small-cell lung cancer.

Antibody-based immunotherapy for ovarian cancer: where are we at?

Cytoreductive surgery and chemotherapy continue to be the mainstay of ovarian cancer treatment. However, as mortality from advanced ovarian cancer remains very high, novel therapies are required to be integrated into existing treatment regimens. Immunotherapy represents an alternative and rational therapeutic approach for ovarian cancer based on a body of evidence supporting a protective role of the immune system against these cancers, and on the clinical success of immunotherapy in other malignancies. Whether or not immunotherapy will have a role in the future management of ovarian cancer is too early to tell, but research in this field is active. This review will discuss recent clinical developments of selected immunotherapies for ovarian cancer which fulfil the following criteria: (i) they are antibody-based, (ii) target a distinct immunological pathway, and (iii) have reached the clinical trial stage. Specifically, the focus is on Catumaxomab (anti-EpCAM×anti-CD3), Abagovomab, Oregovomab (anti-CA125), Daclizumab (anti-CD25), Ipilimumab (anti-CTLA-4), and MXD-1105 (anti-PD-L1). Catumaxomab has reached phase III clinical trials and exhibits promise with reports, showing that it can cause a significant and sustained reduction in ascites. Phase I-III clinical trials continue to be conducted on the other antibodies, some of which have had encouraging reports. We will also provide our perspective on the future of immunotherapy for ovarian cancer, and how it may be best employed in treatment regimens.

Breathing new life into immunotherapy: review of melanoma, lung and kidney cancer

Previously, clinical approaches to using the immune system against cancer focused on vaccines that intended to specifically initiate or amplify a host response against evolving tumours. Although vaccine approaches have had some clinical success, most cancer vaccines fail to induce objective tumour shrinkage in patients. More-recent approaches have centred on a series of molecules known as immune checkpoints-whose natural function is to restrain or dampen a potentially over-exuberant response. Blocking immune checkpoint molecules with monoclonal antibodies has emerged as a viable clinical strategy that mediates tumour shrinkage in several cancer types. In addition to being part of the current treatment armamentarium for metastatic melanoma, immune checkpoint blockade is currently undergoing phase III testing in several cancer types.

Biomarkers for immunostimulatory monoclonal antibodies in combination strategies for melanoma and other tumor types

Modulation of the immune system by targeting coinhibitory and costimulatory receptors has become a promising new approach of immunotherapy for cancer. The recent approval of the CTLA-4-blocking antibody ipilimumab for the treatment of melanoma was a watershed event, opening up a new era in the field of immunotherapy. Ipilimumab was the first treatment to ever show enhanced overall survival (OS) for patients with stage IV melanoma. However, measuring response rates using standard Response Evaluation Criteria in Solid Tumors (RECIST) or modified World Health Organization criteria or progression-free survival does not accurately capture the potential for clinical benefit for ipilimumab-treated patients. As immunotherapy approaches are translated into more tumor types, it is important to study biomarkers, which may be more predictive of OS to identify the patients most likely to have clinical benefit. Ipilimumab is the first-in-class of a series of immunomodulating antibodies that are in clinical development. Anti-PD1 (nivolumab and MK-3475), anti-PD-L1 (BMS-936 559, RG7446, and MEDI4736), anti-CD137 (urelumab), anti-OX40, anti-GITR, and anti-CD40 monoclonal antibodies are just some of the agents that are being actively investigated in clinical trials, each having the potential for combination with the ipilimumab to enhance its effectiveness. Development of rational combinations of immunomodulatory antibodies with small-molecule pathway inhibitor therapies such as vemurafenib makes the discovery of predictive biomarkers even more important. Identifying reliable biomarkers is a necessary step in personalizing the treatment of each patient's cancer through a baseline assessment of tumor gene expression and/or immune profile to optimize therapy for the best chance of therapeutic success.

Clinical development of immunostimulatory monoclonal antibodies and opportunities for combination

Immune system responses are under the control of extracellular biomolecules, which express functions in receptors present on the surface of cells of the immune system, and thus are amenable to be functionally modulated by monoclonal antibodies. Some of these mechanisms are activating and dictate whether the response ensues, while others play the role of powerful repressors. Antagonist antibodies acting on such repressors result in enhanced immune responses, a goal that is also achieved with agonist antibodies acting on the activating receptors. With these simple logics, a series of therapeutic agents are under clinical development and one of them directed at the CTL-associated antigen 4 (CTLA-4) inhibitory receptor (ipilimumab) has been approved for the treatment of metastatic melanoma. The list of antagonist agents acting on repressors under development includes anti-CTLA-4, anti-PD-1, anti-PD-L1 (B7-H1), anti-KIR, and anti-TGF-β. Agonist antibodies currently being investigated in clinical trials target CD40, CD137 (4-1BB), CD134 (OX40), and glucocorticoid-induced TNF receptor (GITR). A blossoming preclinical pipeline suggests that other active targets will also be tested in patients in the near future. All of these antibodies are being developed as conventional monoclonal immunoglobulins, but other engineered antibody formats or RNA aptamers are under preclinical scrutiny. The "dark side" of these immune interventions is that they elicit autoimmune/inflammatory reactions that can be severe in some patients. A critical and, largely, pending subject is to identify reliable predictive biomarkers both for efficacy and immune toxicity. Preclinical and early clinical studies indicate a tremendous potential to further improve efficacy, using combinations from among these new agents that frequently act in a synergistic fashion. Combinations with other more conventional means of treatment such as radiotherapy, chemotherapy, or cancer vaccines also hold much promise.

Anti-cytotoxic T lymphocyte antigen-4 antibodies in melanoma

Approaches aimed at enhancement of the tumor specific response have provided proof for the rationale of immunotherapy in cancer, both in animal models and in humans. Ipilimumab, an anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) antibody, is a new generation immunotherapeutic agent that has shown activity in terms of disease free and overall survival in metastatic melanoma patients. Its use was approved by the US Food and Drug Administration in March 2011 to treat patients with late stage melanoma that has spread or that cannot be removed by surgery. The mechanism of action of CTLA-4 antibodies in the activation of an antitumor immune response and selected clinical studies of ipilimumab in advanced melanoma patients are discussed. Ipilimumab treatment has been associated with immune related adverse events due to T-cell activation and proliferation. Most of these serious adverse effects are associated with the gastrointestinal tract and include severe diarrhea and colitis. The relationship between immune related adverse events and antitumor activity associated with ipilimumab was explored in clinical studies. Potential biomarkers predictive for clinical response and survival in patients treated with anti-CTLA-4 therapy are presently under investigation. Besides the conventional patterns of response and stable disease as defined by standard Response Evaluation Criteria in Solid Tumors criteria, in subsets of patients, ipilimumab has shown patterns of delayed clinical activity which were associated with an improved overall survival. For this reason a new set of response criteria for tumor immunotherapy has been proposed, which was termed immune related response criteria. These new criteria are presently used to better analyze clinical activity of immunotherapeutic regimens. Ipilimumab is currently under investigation in combination with other treatments, such as chemotherapy, target agents, radiotherapy, and other immuno-therapeutic regimens.

Tremelimumab for patients with chemotherapy-resistant advanced malignant mesothelioma: an open-label, single-arm, phase 2 trial

BACKGROUND

Monoclonal antibodies to cytotoxic T-lymphocyte antigen 4 (CTLA4) have therapeutic activity in different tumour types. We aimed to investigate the efficacy, safety, and immunological activity of the anti-CTLA4 monoclonal antibody, tremelimumab, in advanced malignant mesothelioma.

METHODS

In our open-label, single-arm, phase 2 study, we enrolled patients aged 18 years or older with measurable, unresectable malignant mesothelioma and progressive disease after a first-line platinum-based regimen. Eligible patients had to have a life expectancy of 3 months or more, an Eastern Cooperative Oncology Group performance status of 2 or less, and no history of autoimmune disease. Patients received tremelimumab 15 mg/kg intravenously once every 90 days until progressive disease or severe toxicity. The primary endpoint was the proportion of patients who achieved an objective response (complete or partial response), with a target response rate of 17% according to the modified Response Evaluation Criteria in Solid Tumors (RECIST) for pleural malignant mesothelioma or standard RECIST 1.0 for peritoneal malignant mesothelioma. Analyses were done according to intention to treat. This trial is registered with EudraCT, number 2008-005171-95, and ClinicalTrials.gov, number NCT01649024.

FINDINGS

Between May 27, 2009, and Jan 10, 2012, we enrolled 29 patients. All patients received at least one dose of tremelimumab (median two doses, range one to nine). No patients had a complete response and two patients (7%) had a durable partial response (one lasting 6 months and one lasting 18 months); one partial response occurred after initial progressive disease. Thus, the study did not reach its primary endpoint. However, we noted disease control in nine (31%) patients and a median progression-free survival of 6·2 months (95% CI 1·3-11·1) and a median overall survival of 10·7 months (0·0-21·9). 27 patients (93%) had at least one grade 1-2 treatment-emergent adverse event (mainly cutaneous rash, pruritus, colitis, or diarrhoea), and four patients (14%) had at least one grade 3-4 treatment-emergent adverse event (two gastrointestinal, one neurological, two hepatic, and one pancreatic).

INTERPRETATION

Although the effect size was small in our phase 2 trial, tremelimumab seemed to have encouraging clinical activity and an acceptable safety and tolerability profile in previously treated patients with advanced malignant mesothelioma.

FUNDING

Associazione Italiana per la Ricerca sul Cancro, Istituto Toscano Tumori, Pfizer, and Fondazione Buzzi Unicem.

Use of ipilimumab in the treatment of melanoma

Ipilimumab is a monoclonal antibody directed against cytotoxic T-lymphocyte antigen-4 that has been approved by the US Food and Drug Administration for the treatment of metastatic melanoma. Phase III trials have demonstrated an overall survival benefit with its use when compared with standard treatments and other investigational therapies. However, the drug poses a notable challenge, given its propensity for toxicity, and requires close surveillance when administered in clinical practice. This review discusses the mechanism of action for ipilimumab, its preclinical data, and the clinical trials that led to its approval by the Food and Drug Administration in 2011.

CIMT 2013: advancing targeted therapies--report on the 11th Annual Meeting of the Association for Cancer Immunotherapy, May 14-16 2013, Mainz, Germany

The 11th Annual Meeting of Association for Cancer Immunotherapy (CIMT) welcomed more than 700 scientists around the world to Mainz, Germany and continued to be the largest immunotherapy meeting in Europe. Renowned speakers from various fields of cancer immunotherapy gave lectures under CIMT2013’s tag: “Advancing targeted therapies” the highlights of which are summarized in this meeting report.

Development of ipilimumab: a novel immunotherapeutic approach for the treatment of advanced melanoma

The immunotherapeutic agent ipilimumab has helped address a significant unmet need in the treatment of advanced melanoma. Ipilimumab is a fully human monoclonal antibody that targets cytotoxic T-lymphocyte antigen-4 (CTLA-4), thereby augmenting antitumor immune responses. After decades in which a number of clinical trials were conducted, ipilimumab was the first therapy to improve overall survival in a randomized, controlled phase III trial of patients with advanced melanoma. These results led to the regulatory approval of ipilimumab at 3 mg/kg for the treatment of unresectable or metastatic melanoma. More than 17,000 patients worldwide have received ipilimumab, either as a commercial drug at 3 mg/kg or in clinical trials and expanded access programs at different doses. Consistent with its proposed mechanism of action, the most common toxicities associated with ipilimumab therapy are inflammatory in nature. These immune-related adverse events were mostly reversible when effective treatment guidelines were followed. Importantly, long-term follow-up of patients who received ipilimumab in a phase III trial showed that 24% survived at least two years, and in phase II studies, a proportion of patients survived at least five years. Evaluation of ipilimumab is ongoing in the adjuvant setting for melanoma, and for advanced disease in nonsmall cell lung, small cell lung, prostate, ovarian, and gastric cancers.

Ipilimumab alone or in combination with radiotherapy in metastatic castration-resistant prostate cancer: results from an open-label, multicenter phase I/II study

BACKGROUND

This phase I/II study in patients with metastatic castration-resistant prostate cancer (mCRPC) explored ipilimumab as monotherapy and in combination with radiotherapy, based on the preclinical evidence of synergistic antitumor activity between anti-CTLA-4 antibody and radiotherapy.

PATIENTS AND METHODS

In dose escalation, 33 patients (≥6/cohort) received ipilimumab every 3 weeks × 4 doses at 3, 5, or 10 mg/kg or at 3 or 10 mg/kg + radiotherapy (8 Gy/lesion). The 10-mg/kg cohorts were expanded to 50 patients (ipilimumab monotherapy, 16; ipilimumab + radiotherapy, 34). Evaluations included adverse events (AEs), prostate-specific antigen (PSA) decline, and tumor response.

RESULTS

Common immune-related AEs (irAEs) among the 50 patients receiving 10 mg/kg ± radiotherapy were diarrhea (54%), colitis (22%), rash (32%), and pruritus (20%); grade 3/4 irAEs included colitis (16%) and hepatitis (10%). One treatment-related death (5 mg/kg group) occurred. Among patients receiving 10 mg/kg ± radiotherapy, eight had PSA declines of ≥50% (duration: 3-13+ months), one had complete response (duration: 11.3+ months), and six had stable disease (duration: 2.8-6.1 months).

CONCLUSIONS

In mCRPC patients, ipilimumab 10 mg/kg ± radiotherapy suggested clinical antitumor activity with disease control and manageable AEs. Two phase III trials in mCRPC patients evaluating ipilimumab 10 mg/kg ± radiotherapy are ongoing. ClinicalTrials.gov identifier: NCT00323882.

Ipilimumab-associated colitis: CT findings

OBJECTIVE

The purpose of this article is to describe the CT findings of ipilimumab-associated colitis.

MATERIALS AND METHODS

In this retrospective study, 16 patients diagnosed with ipilimumab-associated colitis and available CT scans obtained at the time of symptoms were found by a search through the electronic medical record database. Two radiologists reviewed the CT images in consensus for the presence of bowel wall thickening, bowel mucosal enhancement, bowel distention, pneumatosis, pericolic fat stranding, and mesenteric vessel engorgement. Medical records were reviewed to note clinical features, management, and outcome.

RESULTS

The common CT findings of ipilimumab-associated colitis were mesenteric vessel engorgement (13/16 [81.3%]) followed by bowel wall thickening (12/16 [75%]) and fluid-filled colonic distention (4/16 [25%]). None of the patients had pneumatosis or halo or target signs. Two distinct CT patterns of ipilimumab-associated colitis were observed: first, the diffuse colitis pattern (n = 12), which is characterized by mesenteric vessel engorgement with mild diffuse bowel wall thickening or fluid-filled distended colon; and, second, the segmental colitis associated with diverticulosis (SCAD) pattern (n = 4), which is characterized by segmental moderate wall thickening and associated pericolic fat stranding in a segment of preexisting diverticulosis. Clinical features and management also differed according to the CT pattern. Patients with the diffuse colitis pattern presented with watery diarrhea and were treated with steroids, whereas the patients with the SCAD pattern presented with mixed watery and bloody diarrhea and cramping pain and were treated with steroids and antibiotics.

CONCLUSION

Two different radiologic and clinical manifestations of ipilimumab-associated colitis were observed: the diffuse colitis pattern and the SCAD pattern.

Adoptive T-cell transfer in melanoma

Immunotherapy holds a highly promising treatment approach for metastatic melanoma patients. Adoptive cell transfer (ACT) involves the ex vivo expansion of autologous antitumor reactive lymphocytes and their reinfusion into lymphodepleted patients, accompanied by IL-2 administration. ACT with tumor-infiltrating T lymphocytes demonstrates objective clinical responses in 50-72% of the patients, including 10-40% complete responses and was shown to produce durable disease control with long progression-free survival. Tumor-infiltrating T-lymphocyte ACT might even have curative potential as the vast majority of the complete responders are without any evidence of disease many years after treatment. Other adoptive transfer studies employ the genetic modification of T lymphocytes with genes encoding tumor-specific T cell receptors or antibody-based chimeric antigen receptors. These approaches opened numerous possibilities to treat cancers other than melanoma. In this article we will summarize the ACT strategies in melanoma, the new developments in this field and combinations with other therapies.

Exposure-response relationships of the efficacy and safety of ipilimumab in patients with advanced melanoma

PURPOSE

This retrospective analysis was conducted to characterize ipilimumab exposure-response relationships for measures of efficacy and safety in patients with advanced melanoma.

EXPERIMENTAL DESIGN

Data were pooled from 498 patients who received ipilimumab monotherapy at 0.3, 3, or 10 mg/kg in 1 of 4 completed phase II clinical trials. The relationships between steady-state ipilimumab trough concentration (Cminss), complete or partial tumor response (CR or PR), and safety [immune-related adverse events (irAEs)] were described by logistic regression models. The relationship between exposure and overall survival was characterized using a Cox proportional-hazards model.

RESULTS

The steady-state trough concentration of ipilimumab was found to be a significant predictor of a CR or PR (P < 0.001). Model-based estimates indicate that the probabilities of a CR or PR at median Cminss for the 0.3, 3, and 10 mg/kg groups were 0.6%, 4.9%, and 11.6%, respectively. Overall survival at the median Cminss for ipilimumab at 0.3 mg/kg was estimated to be 0.85- and 0.58-fold lower relative to that at the median Cminss for 3 and 10 mg/kg, respectively. Model-based estimates indicate that the probabilities of a grade 3 or more irAE at the median Cminss for the 0.3, 3, and 10 mg/kg doses were 3%, 13%, and 24%, respectively.

CONCLUSIONS

Higher doses of ipilimumab produce greater Cminss that may be associated with increased tumor responses, longer survival, and higher rates of irAEs. The efficacy and safety of ipilimumab at 3 versus 10 mg/kg in patients with advanced melanoma is being evaluated in an ongoing phase III trial.

Four-year survival rates for patients with metastatic melanoma who received ipilimumab in phase II clinical trials

BACKGROUND

This analysis was carried out to evaluate the long-term survival of patients with metastatic melanoma who received ipilimumab, a fully human monoclonal antibody that binds to cytotoxic T-lymphocyte antigen-4, in clinical trials.

PATIENTS AND METHODS

Patients received ipilimumab in one of three completed phase II clinical trials (CA184-008, CA184-022, and CA184-007). Previously treated patients were enrolled in all studies, and treatment-naïve patients were also included in study CA184-007. Patients received ipilimumab at a dose of 10 mg/kg in studies CA184-008 and CA184-007, and at doses of 0.3, 3, or 10 mg/kg in study CA184-022. Ipilimumab was given every 3 weeks for four doses, and eligible patients could receive ipilimumab maintenance therapy every 12 weeks. In study CA184-022, patients could cross over to be retreated with ipilimumab at 10 mg/kg upon disease progression. Ongoing survival follow-up is conducted in a companion study, CA184-025.

RESULTS

Four-year survival rates [95% confidence interval (95% CI)] for previously treated patients who received ipilimumab at 0.3, 3, or 10 mg/kg were 13.8% [6.1-22.5], 18.2% [9.5-27.6], and 19.7% [13.4-26.5] to 28.4% [13.9-44.2], respectively. In treatment-naïve patients who received ipilimumab at 10 mg/kg, 4-year survival rates were 37.7% [18.6-57.4] to 49.5% [23.8-75.4].

CONCLUSIONS

These results demonstrate durable survival in a significant proportion of patients with metastatic melanoma who received ipilimumab therapy.

Rationale for targeting the immune system through checkpoint molecule blockade in the treatment of non-small-cell lung cancer

BACKGROUND

Treatments of non-small-cell lung cancer (NSCLC)-particularly of the squamous subtype-are limited. In this article, we describe the immunomodulatory environment in NSCLC and the potential for therapeutic targeting of the immune system through cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1) immune-checkpoint pathway blockade.

MATERIALS AND METHODS

We searched PubMed and presented abstracts for publications describing the clinical benefit of checkpoint blockade in NSCLC.

RESULTS

Antibody-mediated checkpoint molecule blockade is being investigated in NSCLC, and of these approaches, the anti-CTLA-4 antibody ipilimumab has undergone the most extensive clinical study. By targeting the immune system rather than specific antigens, checkpoint blockade agents differ from vaccine therapy. In a phase II study in advanced NSCLC, phased ipilimumab with chemotherapy demonstrated the greatest efficacy in squamous NSCLC. A phase I study of nivolumab, an anti-PD-1 antibody, has suggested that this agent is also active against squamous and non-squamous NSCLC. Ongoing phase III studies are evaluating the therapeutic potential of these agents.

CONCLUSIONS

Although treatment options for NSCLC are limited, a better understanding of the immune profile of this disease has facilitated the development of immunotherapeutics that target checkpoint blockade molecules, and clinical evaluation to date supports combining checkpoint blockade with chemotherapy for squamous NSCLC.

Ipilimumab: A First-in-Class T-Cell Potentiator for Metastatic Melanoma

Ipilimumab, a fully human anti-cytotoxic T-lymphocyte antigen-4 monoclonal antibody that potentiates antitumor T-cell responses, has demonstrated improved survival in previously treated and treatment-naïve patients with unresectable stage III/IV melanoma. Survival benefit has also been shown in diverse patient populations, including those with brain metastases. In 2011, ipilimumab (3 mg/kg every 3 weeks for 4 doses) was approved by the Food and Drug Administration for unresectable or metastatic melanoma. Ipilimumab can induce novel response patterns for which immune-related response criteria have been proposed. irAEs are common but are usually low grade; higher grades can be severe and life-threatening. irAEs are usually manageable using established guidelines emphasizing vigilance and prompt intervention. This agent provides an additional therapeutic option in metastatic melanoma, and guidelines for management of adverse events facilitate clinical implementation of this new agent.

Immune-mediated adverse events associated with ipilimumab ctla-4 blockade therapy: the underlying mechanisms and clinical management

Immunomodulation with the anti-CTLA-4 monoclonal antibody ipilimumab has been shown to extend overall survival (OS) in previously treated and treatment-naive patients with unresectable stage III or IV melanoma. Blockade of CTLA-4 signaling with ipilimumab prolongs T-cell activation and restores T-cell proliferation, thus amplifying T-cell-mediated immunity and the patient's capacity to mount an effective antitumor immune response. While this immunostimulation has unprecedented OS benefits in the melanoma setting, it can also result in immune-mediated effects on various organ systems, leading to immune-related adverse events (irAEs). Ipilimumab-associated irAEs are common and typically low grade and manageable, but can also be serious and life threatening. The skin and gastrointestinal tract are most frequently affected, while hepatic, endocrine, and neurologic events are less common. With proper management, most irAEs resolve within a relatively short time, with a predictable resolution pattern. Prompt and appropriate management of these irAEs is essential and treatment guidelines have been developed to assist oncologists and their teams. Implementation of these irAE management algorithms will help ensure that patients are able to benefit from ipilimumab therapy with adequate control of toxicities.

Anti-CTLA-4 antibodies of IgG2a isotype enhance antitumor activity through reduction of intratumoral regulatory T cells

Antitumor activity of CTLA-4 antibody blockade is thought to be mediated by interfering with the negative regulation of T-effector cell (Teff) function resulting from CTLA-4 engagement by B7-ligands. In addition, a role for CTLA-4 on regulatory T cells (Treg), wherein CTLA-4 loss or inhibition results in reduced Treg function, may also contribute to antitumor responses by anti-CTLA-4 treatment. We have examined the role of the immunoglobulin constant region on the antitumor activity of anti-CTLA-4 to analyze in greater detail the mechanism of action of anti-CTLA-4 antibodies. Anti-CTLA-4 antibody containing the murine immunoglobulin G (IgG)2a constant region exhibits enhanced antitumor activity in subcutaneous established MC38 and CT26 colon adenocarcinoma tumor models compared with anti-CTLA-4 containing the IgG2b constant region. Interestingly, anti-CTLA-4 antibodies containing mouse IgG1 or a mutated mouse IgG1-D265A, which eliminates binding to all Fcγ receptors (FcγR), do not show antitumor activity in these models. Assessment of Teff and Treg populations at the tumor and in the periphery showed that anti-CTLA-4-IgG2a mediated a rapid and dramatic reduction of Tregs at the tumor site, whereas treatment with each of the isotypes expanded Tregs in the periphery. Expansion of CD8(+) Teffs is observed with both the IgG2a and IgG2b anti-CTLA-4 isotypes, resulting in a superior Teff to Treg ratio for the IgG2a isotype. These data suggest that anti-CTLA-4 promotes antitumor activity by a selective reduction of intratumoral Tregs along with concomitant activation of Teffs.

[Immunotherapy for non-small cell lung cancer--novel approaches to improve patient outcome]

简介

通常，非小细胞肺癌（non-small cell lung cancer, NSCLC）诊断已为晚期，且预后较差。目前的NSCLC标准治疗总体治愈率低，有必要开发新的治疗方法。我们在本综述中提供了最新的免疫治疗干预临床数据，该手段可能能够提高免疫系统对细胞的应答。

方法

我们针对临床应用免疫疗法治疗NSCLC，检索了PubMed上的文章以及最近肿瘤学术会议上的摘要。

结果

Ⅱ期临床研究结果表明，靶向肿瘤细胞本身或其异常表达的肿瘤标志物的疫苗治疗（mucin1，黑色素瘤相关抗原3，或表皮生长因子），有望作为NSCLC免疫疗法。非抗原免疫治疗，如抗细胞毒T淋巴细胞抗原4单克隆抗体、talactoferrin alfa和toll-样受体9拮抗剂，作用于激活的免疫系统，与肿瘤抗原无关，可用于晚期NSCLC的治疗。目前一些免疫治疗正在进行Ⅲ期研究，以确定最佳治疗方案，并与NSCLC标准治疗对照，确定其临床疗效。

结论

越来越多的证据表明肺部肿瘤存在免疫应答。免疫治疗，包括疫苗治疗和非抗原免疫调节方法，可改善NSCLC的预后。而且，提高抗肿瘤免疫应答的治疗，与化疗有协同作用。生物标志物的明确以及免疫治疗作用机制的进一步阐明对于确定哪些患者更可能从免疫治疗中获益至关重要。

Is there a role for immune checkpoint blockade with ipilimumab in prostate cancer?

Treatment for advanced prostate cancer has and will continue to grow increasingly complex, owing to the introduction of multiple new therapeutic approaches with the potential to substantially improve outcomes for this disease. Agents that modulate the patient's immune system to fight prostate cancer - immunotherapeutics - are among the most exciting of these new approaches. The addition of antigen-specific immunotherapy to the treatment of castration-resistant prostate cancer (CRPC) has paved the way for additional research that seeks to augment the activity of the immune system itself. The monoclonal antibody ipilimumab, approved in over 40 countries to treat advanced melanoma and currently under phase 2 and 3 investigation in prostate cancer, is thought to act by augmenting immune responses to tumors through blockade of cytotoxic T-lymphocyte antigen 4, an inhibitory immune checkpoint molecule. Ipilimumab has been studied in seven phase 1 and 2 clinical trials that evaluated various doses, schedules, and combinations across the spectrum of patients with advanced prostate cancer. The CRPC studies of ipilimumab to date suggest that the agent is active in prostate cancer as monotherapy or in combination with radiotherapy, docetaxel, or other immunotherapeutics, and that the adverse event profile is as expected given the safety data in advanced melanoma. The ongoing phase 3 program will further characterize the risk/benefit profile of ipilimumab in chemotherapy-naïve and -pretreated CRPC.