Immune-Related Adverse Events Associated with Immune Checkpoint Blockade

Ipilimumab, an immune checkpoint inhibitor targeting CTLA-4, prolongs survival in a subset of patients with metastatic melanoma (MM) but can induce immune-related adverse events, including enterocolitis. We hypothesized that baseline gut microbiota could predict ipilimumab anti-tumor response and/or intestinal toxicity.

Background Malignant cells of classical Hodgkin lymphoma (cHL) are characterised by genetic alterations at the 9p24·1 locus. This leads to overexpression of the programmed death 1 (PD-1) ligands and enables tumour cells to evade immune surveillance. A phase 1b study showed that nivolumab, a PD-1-blocking antibody, produced a high response rate in patients with relapsed and refractory cHL, with an acceptable safety profile. This phase 2 study assessed the clinical benefit of nivolumab monotherapy in patients with cHL after autologous stem-cell transplantation and brentuximab vedotin failure. Methods This ongoing phase 2 study (NCT02181738) assessed the efficacy and safety of nivolumab, administered intravenously over 60 minutes at 3 mg/kg every 2 weeks, in adult patients with cHL who had failed both autologous stem-cell transplantation and brentuximab vedotin. The primary endpoint was objective response rate by independent radiologic review committee (IRRC) assessment. Secondary and other endpoints included duration of response, safety, and assessment of PD-L1 and PD-L2 loci and PD-L1 and PD-L2 protein expression. Findings Among 80 treated patients, the median number of prior therapies was four (range 3–15). With a mean (SD) follow-up of 8·6 months (2·02), objective response rate per IRRC was 66·3% (53/80). The most common drug-related adverse events (≥15%) included fatigue, infusion-related reaction, and rash. The most common drug-related grade 3–4 adverse events were neutropenia and increased lipase levels (both n=4). The most common serious adverse event (any grade) was pyrexia (n=3). Interpretation Nivolumab demonstrated a high response rate and an acceptable safety profile in patients with cHL who progressed following autologous stem-cell transplantation and brentuximab vedotin. Nivolumab may therefore provide a novel treatment option for a patient population with a high unmet need. Ongoing follow-up will help to assess the durability of response. Funding Bristol-Myers Squibb.