Tumour- and class-specific patterns of immune-related adverse events of immune checkpoint inhibitors: a systematic review

Ipilimumab is a human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen 4 and has shown promising activity in advanced melanoma. We aimed to ascertain the antitumour efficacy of ipilimumab in patients with advanced melanoma. We undertook a randomised, double-blind, phase 2 trial in 66 centres from 12 countries. 217 patients with previously treated stage III (unresectable) or stage IV melanoma were randomly assigned a fixed dose of ipilimumab of either 10 mg/kg (n=73), 3 mg/kg (n=72), or 0.3 mg/kg (n=72) every 3 weeks for four cycles (induction) followed by maintenance therapy every 3 months. Randomisation was done with a permuted block procedure, stratified on the basis of type of previous treatment. The primary endpoint was best overall response rate (the proportion of patients with a complete or partial response, according to modified WHO criteria). Efficacy analyses were done by intention to treat, whereas safety analyses included patients who received at least one dose of ipilimumab. This study is registered with ClinicalTrials.gov, number NCT00289640. The best overall response rate was 11.1% (95% CI 4.9-20.7) for 10 mg/kg, 4.2% (0.9-11.7) for 3 mg/kg, and 0% (0.0-4.9) for 0.3 mg/kg (p=0.0015; trend test). Immune-related adverse events of any grade arose in 50 of 71, 46 of 71, and 19 of 72 patients at doses of 10 mg/kg, 3 mg/kg, and 0.3 mg/kg, respectively; the most common grade 3-4 adverse events were gastrointestinal immune-related events (11 in the 10 mg/kg group, two in the 3 mg/kg group, none in the 0.3 mg/kg group) and diarrhoea (ten in the 10 mg/kg group, one in the 3 mg/kg group, none in the 0.3 mg/kg group). Ipilimumab elicited a dose-dependent effect on efficacy and safety measures in pretreated patients with advanced melanoma, lending support to further studies at a dose of 10 mg/kg. Bristol-Myers Squibb. Copyright 2010 Elsevier Ltd. All rights reserved.

Programmed cell death 1 (PD-1) inhibitor-related pneumonitis is a rare but clinically serious and potentially life-threatening adverse event. Little is known about its incidence across different tumor types and treatment regimens.

A large number of cancer-associated gene products evoke immune recognition, but host reactions rarely impede disease progression. The weak immunogenicity of nascent tumors contributes to this failure in host defense. Therapeutic vaccines that enhance dendritic cell presentation of cancer antigens increase specific cellular and humoral responses, thereby effectuating tumor destruction in some cases. The attenuation of T cell activation by cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) further limits the potency of tumor immunity. In murine systems, the administration of antibodies that block CTLA-4 function inhibits the growth of moderately immunogenic tumors and, in combination with cancer vaccines, increases the rejection of poorly immunogenic tumors, albeit with a loss of tolerance to normal differentiation antigens. To gain a preliminary assessment of the biologic activity of antagonizing CTLA-4 function in humans, we infused a CTLA-4 blocking antibody (MDX-CTLA4) into nine previously immunized advanced cancer patients. MDX-CTLA4 stimulated extensive tumor necrosis with lymphocyte and granulocyte infiltrates in three of three metastatic melanoma patients and the reduction or stabilization of CA-125 levels in two of two metastatic ovarian carcinoma patients previously vaccinated with irradiated, autologous granulocyte-macrophage colony-stimulating factor-secreting tumor cells. MDX-CTLA4 did not elicit tumor necrosis in four of four metastatic melanoma patients previously immunized with defined melanosomal antigens. No serious toxicities directly attributable to the antibody were observed, although five of seven melanoma patients developed T cell reactivity to normal melanocytes. These findings suggest that CTLA-4 antibody blockade increases tumor immunity in some previously vaccinated cancer patients.