Immunology and Biotherapies

Abstract

Enhancing immune responses with immune-modulatory monoclonal antibodies directed to inhibitory immune receptors is a promising modality in cancer therapy. Clinical efficacy has been demonstrated with antibodies blocking inhibitory immune checkpoints such as cytotoxic T lymphocyte–associated antigen 4 (CTLA-4) or PD-1/PD-L1. Treatment with ipilimumab, a fully human CTLA-4–specific mAb, showed durable clinical efficacy in metastatic melanoma; its mechanism of action is, however, only partially understood. This is a study of 29 patients with advanced cutaneous melanoma treated with ipilimumab. We analyzed peripheral blood mononuclear cells (PBMCs) and matched melanoma metastases from 15 patients responding and 14 not responding to ipilimumab by multicolor flow cytometry, antibody-dependent cell-mediated cytotoxicity (ADCC) assay, and immunohistochemistry. PBMCs and matched tumor biopsies were collected 24 h before (i.e., baseline) and up to 4 wk after ipilimumab. Our findings show, to our knowledge for the first time, that ipilimumab can engage ex vivo FcγRIIIA (CD16)-expressing, nonclassical monocytes resulting in ADCC-mediated lysis of regulatory T cells (Tregs). In contrast, classical CD14++CD16−monocytes are unable to do so. Moreover, we show that patients responding to ipilimumab display significantly higher baseline peripheral frequencies of nonclassical monocytes compared with nonresponder patients. In the tumor microenvironment, responders have higher CD68+/CD163+ macrophage ratios at baseline and show decreased Treg infiltration after treatment. Together, our results suggest that anti–CTLA-4 therapy may target Tregs in vivo. Larger translational studies are, however, warranted to substantiate this mechanism of action of ipilimumab in patients.

The BJC is owned by Cancer Research UK, a charity dedicated to understanding the causes, prevention and treatment of cancer and to making sure that the best new treatments reach patients in the clinic as quickly as possible.

Fig 1. Targets of antibody immune modulators (Page et al, 2014)

background:  

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

methods:  

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

results:  

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

conclusions:  

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

TIL Technology 

In the early stages of cancer, special immune cells known as tumor infiltrating lymphocytes (TILs) migrate to the tumor and launch an attack.  However, this effect is usually short-lived because cancer adapts to evade immune detection and suppress immune response. Lion’s TIL technology is designed to overcome the immunosuppressive effects of cancer, while leveraging and enhancing the power of TILs to treat, and potentially cure, all solid tumors.

Our TIL technology has demonstrated robust efficacy in Phase 2 clinical trials, indicating objective response rates of 49% in Stage 4 metastatic melanoma.  Based on an adoptive cell therapy regimen developed by Steven A. Rosenberg, MD, chief of surgery at National Cancer Institute (NCI), it is currently in use as a physician-sponsored investigational treatment for Stage IV metastatic melanoma at NCI, MD Anderson Cancer Center, and the H. Lee Moffitt Cancer & Research Institute.

"OS & Long-Term Safety of #Nivolumab in Patients With Previously Treated Advanced #NSCLC" JCO http://t.co/TjxJ8tP1Sr

Purpose Programmed death 1 is an immune checkpoint that suppresses antitumor immunity. Nivolumab, a fully human immunoglobulin G4 programmed death 1 immune checkpoint inhibitor antibody, was active and generally well tolerated in patients with advanced solid tumors treated in a phase I trial with expansion cohorts. We report overall survival (OS), response durability, and long-term safety in patients with non–small-cell lung cancer (NSCLC) receiving nivolumab in this trial.

Patients and Methods Patients (N = 129) with heavily pretreated advanced NSCLC received nivolumab 1, 3, or 10 mg/kg intravenously once every 2 weeks in 8-week cycles for up to 96 weeks. Tumor burden was assessed by RECIST (version 1.0) after each cycle.

Results Median OS across doses was 9.9 months; 1-, 2-, and 3-year OS rates were 42%, 24%, and 18%, respectively, across doses and 56%, 42%, and 27%, respectively, at the 3-mg/kg dose (n = 37) chosen for further clinical development. Among 22 patients (17%) with objective responses, estimated median response duration was 17.0 months. An additional six patients (5%) had unconventional immune-pattern responses. Response rates were similar in squamous and nonsquamous NSCLC. Eighteen responding patients discontinued nivolumab for reasons other than progressive disease; nine (50%) of those had responses lasting > 9 months after their last dose. Grade 3 to 4 treatment-related adverse events occurred in 14% of patients. Three treatment-related deaths (2% of patients) occurred, each associated with pneumonitis.

Conclusion Nivolumab monotherapy produced durable responses and encouraging survival rates in patients with heavily pretreated NSCLC. Randomized clinical trials with nivolumab in advanced NSCLC are ongoing.

Until recently, most immunotherapeutic approaches used to fight cancer were ineffective, counteracted by the tumour’s ability to evade immune attack. However, extensive research has improved our understanding of tumour immunology and enabled the development of novel treatments that can harness the patient’s immune system and prevent immune escape. Over the last few years, through numerous clinical trials and real-world experience, we have accumulated a large amount of evidence regarding the potential for long-term survival with immunotherapy agents in various types of malignancy. The results of these studies have also highlighted a number of recurring observations with immuno-oncology agents, including their potential for clinical application across a broad patient population and for both conventional and unconventional response patterns. Furthermore, given the numerous immune checkpoints that exist and the multiple mechanisms used by tumours to escape the immune system, targeting distinct checkpoint pathways using combination approaches is an attractive therapeutic strategy with the potential to further enhance the antitumour immune response.

Fig 1. Immuno-oncology agentsa in clinical development across multiple tumour types.aSelected therapies and tumour types are shown: additional agents are, for example in phase 1 studies in patients with solid tumours [12]. AML, acute myeloid leukemia; CLL, chronic lymphocytic leukaemia; CRC, colorectal cancer; CRPC, castration-resistant prostate cancer; CTLA-4, cytotoxic T-lymphocyte antigen-4; GIST, gastrointestinal stromal tumour; HCC, hepatic cell carcinoma; LAG-3, lymphocyte activation gene 3; mAb, monoclonal antibody; NHL, non-Hodgkin lymphoma; NSCLC, non-small cell lung cancer; PC, prostate cancer; PD1, programmed death 1; RCC, renal cell carcinoma; SCLC, small cell lung cancer.

Ascierto and Marincola Journal of Translational Medicine 2014 12:141   doi:10.1186/1479-5876-12-141

WHITEHOUSE STATION, N.J.--(BUSINESS WIRE)--Merck (NYSE:MRK), known as MSD outside the United States and Canada, today announced that the U.S. 

Food and Drug Administration (FDA) has approved KEYTRUDA® (pembrolizumab) at a dose of 2 mg/kg every three weeks for the treatment of patients with unresectable or metastatic melanoma and disease progression following ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor. This indication is approved under accelerated approval based on tumor response rate and durability of response. An improvement in survival or disease-related symptoms has not yet been established. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

KEYTRUDA is the first anti-PD-1 (programmed death receptor-1) therapy approved in the United States and received FDA’s Breakthrough Therapy designation for advanced melanoma, which was granted based on the significance of early study findings and the unmet medical need. For the recommended 2 mg/kg dose based on data in 89 patients, the overall response rate was 24 percent (95% CI: 15, 34), with one complete response and 20 partial responses (21/89). At the time of analysis, 86 percent (18/21) of patients with objective responses had ongoing responses with durations ranging from 1.4+ to 8.5+ months, including eight patients with ongoing responses of 6 months or longer. Fourteen percent (3/21) had progression of disease 2.8, 2.9, and 8.2 months after initial response.

KEYTRUDA is a humanized monoclonal antibody that works by increasing the ability of the body’s immune system to fight advanced melanoma. KEYTRUDA blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, and may affect both tumor cells and healthy cells. Immune-mediated adverse reactions occurred with KEYTRUDA including pneumonitis, colitis, hepatitis, hypophysitis, nephritis, hyperthyroidism, and hypothyroidism. Based on the severity of the adverse reaction, KEYTRUDA should be withheld or discontinued and corticosteroids administered. Based on its mechanism of action, KEYTRUDA may cause fetal harm when administered to a pregnant woman. Female patients of reproductive potential should be advised of the potential hazard to a fetus. For more information regarding immune-mediated adverse reactions and use in pregnancy, see “Selected Important Safety Information” below.

Merck is conducting ongoing Phase 2 and 3 clinical studies in advanced melanoma, which are designed to provide further confirmatory evidence for KEYTRUDA in this indication. Merck plans to make KEYTRUDA available within one week from today’s FDA approval.

Study Cohort Supporting the Accelerated FDA Approval of Single-Agent KEYTRUDA

The approval of KEYTRUDA was based on data from a multi-center, open-label, randomized, dose-comparative study cohort of the ongoing KEYNOTE-001 Phase 1b trial in patients with unresectable or metastatic melanoma and progression of disease. Key eligibility criteria included prior treatment with ipilimumab (two or more doses at 3 mg/kg or higher) and a BRAF or MEK inhibitor, if BRAF V600 mutation positive; and disease progression within 24 weeks following the last dose of ipilimumab. Patients were randomized to receive 2 mg/kg (n=89) or 10 mg/kg (n=84) of KEYTRUDA every 3 weeks until unacceptable toxicity or disease progression. The major efficacy outcome measures were confirmed overall response rate as assessed by blinded independent central review using Response Evaluation Criteria in Solid Tumors (RECIST 1.1) and duration of response. Tumor response was assessed every 12 weeks.

Selected Important Safety Information for KEYTRUDA

Pneumonitis occurred in 12 (2.9%) of 411 patients, including Grade 2 or 3 cases in 8 (1.9%) and 1 (0.2%) patients respectively, receiving KEYTRUDA. Monitor patients for signs and symptoms of pneumonitis. Evaluate suspected pneumonitis with radiographic imaging. Administer corticosteroids for Grade 2 or greater pneumonitis. Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 pneumonitis.

Colitis (including microscopic colitis) occurred in 4 (1%) of 411 patients, including Grade 2 or 3 cases in 1 (0.2%) and 2 (0.5%) patients respectively, receiving KEYTRUDA. Monitor patients for signs and symptoms of colitis. Administer corticosteroids for Grade 2 or greater colitis. Withhold KEYTRUDA for Grade 2 or 3; permanently discontinue KEYTRUDA for Grade 4 colitis.

Hepatitis (including autoimmune hepatitis) occurred in 2 (0.5%) of 411 patients, including a Grade 4 case in 1 (0.2%) patient, receiving KEYTRUDA. Monitor patients for changes in liver function. Administer corticosteroids for Grade 2 or greater hepatitis and, based on severity of liver enzyme elevations, withhold or discontinue KEYTRUDA.

Hypophysitis occurred in 2 (0.5%) of 411 patients, including a Grade 2 case in 1 and a Grade 4 case in 1 (0.2% each) patient, receiving KEYTRUDA. Monitor for signs and symptoms of hypophysitis. Administer corticosteroids for Grade 2 or greater hypophysitis. Withhold KEYTRUDA for Grade 2; withhold or discontinue for Grade 3; and permanently discontinue KEYTRUDA for Grade 4 hypophysitis.

Nephritis occurred in 3 (0.7%) patients receiving KEYTRUDA, consisting of one case of Grade 2 autoimmune nephritis (0.2%) and two cases of interstitial nephritis with renal failure (0.5%), one Grade 3 and one Grade 4. Monitor patients for changes in renal function. Administer corticosteroids for Grade 2 or greater nephritis. Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 nephritis.

Hyperthyroidism occurred in 5 (1.2%) of 411 patients, including Grade 2 or 3 cases in 2 (0.5%) and 1 (0.2%) patients respectively, receiving KEYTRUDA. Hypothyroidism occurred in 34 (8.3%) of 411 patients, including a Grade 3 case in 1 (0.2%) patient, receiving KEYTRUDA. Thyroid disorders can occur at any time during treatment. Monitor patients for changes in thyroid function (at the start of treatment, periodically during treatment, and as indicated based on clinical evaluation) and for clinical signs and symptoms of thyroid disorders. Administer corticosteroids for Grade 3 or greater hyperthyroidism. Withhold KEYTRUDA for Grade 3; permanently discontinue KEYTRUDA for Grade 4 hyperthyroidism. Isolated hypothyroidism may be managed with replacement therapy without treatment interruption and without corticosteroids.

The following clinically significant, immune-mediated adverse reactions occurred in less than 1% of patients treated with KEYTRUDA: exfoliative dermatitis, uveitis, arthritis, myositis, pancreatitis, hemolytic anemia, partial seizures arising in a patient with inflammatory foci in brain parenchyma, adrenal insufficiency, myasthenic syndrome, optic neuritis, and rhabdomyolysis.

Based on its mechanism of action, KEYTRUDA may cause fetal harm when administered to a pregnant woman. If used during pregnancy, or if the patient becomes pregnant during treatment, apprise the patient of potential hazard to a fetus. Advise females of reproductive potential to use highly effective contraception during treatment and for 4 months after the last dose of KEYTRUDA.

KEYTRUDA was discontinued for adverse reactions in 6% of 89 patients who received the recommended dose of 2 mg/kg and 9% of 411 patients across all doses studied. Serious adverse reactions occurred in 36% of patients receiving KEYTRUDA. The most frequent serious adverse drug reactions reported in 2% or more of patients were renal failure, dyspnea, pneumonia, and cellulitis.

The most common adverse reactions (reported in ≥20% of patients) were fatigue (47%), cough (30%), nausea (30%), pruritus (30%), rash (29%), decreased appetite (26%), constipation (21%), arthralgia (20%), and diarrhea (20%).

The recommended dose of KEYTRUDA is 2 mg/kg administered as an intravenous infusion over 30 minutes every three weeks until disease progression or unacceptable toxicity. No formal pharmacokinetic drug interaction studies have been conducted with KEYTRUDA.

It is not known whether KEYTRUDA is excreted in human milk. Because many drugs are excreted in human milk, instruct women to discontinue nursing during treatment with KEYTRUDA. Safety and effectiveness of KEYTRUDA have not been established in pediatric patients.

Commitment to Access for KEYTRUDA

Merck is committed to making KEYTRUDA accessible to patients. Reimbursement support for eligible patients receiving KEYTRUDA, including help with out-of-pocket costs and co-pay assistance, is available through The Merck Access Program. For eligible patients who are uninsured, financial assistance is available through Merck’s patient assistance program. More information is available by calling 1-855-257-3932 or visiting www.merckaccessprogram-keytruda.com.

About KEYTRUDA

KEYTRUDA (pembrolizumab) is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2. By binding to the PD-1 receptor and blocking the interaction with the receptor ligands, KEYTRUDA releases the PD-1 pathway-mediated inhibition of the immune response, including the anti-tumor immune response.