IMPORTANCE Limited information is available on the safety of a rechallenge with an immune checkpoint inhibitor (ICI) after an immune-related adverse event (irAE).OBJECTIVE To identify the recurrence rate of the same irAE that prompted discontinuation of ICI therapy after an ICI rechallenge in patients with cancer and to identify the clinical features associated with such recurrences. DESIGN, SETTING, AND PARTICIPANTS This observational, cross-sectional, pharmacovigilance cohort study examined individual case safety reports from the World Health Organization database VigiBase, which contains case reports from more than 130 countries. Case reports were extracted from database inception (1967) to September 1, 2019. All consecutive ICI cases with at least 1 associated irAE were included. MAIN OUTCOMES AND MEASURESThe primary outcome was the rate of recurrence of the initial irAE after an ICI rechallenge. Secondary outcomes included the factors associated with the recurrence after a rechallenge among informative rechallenges, the recurrence rate according to the ICI regimen (anti-programmed cell death 1 or anti-programmed cell death ligand 1 monotherapy, anti-cytotoxic T-lymphocyte antigen-4 monotherapy, or combination therapy), and the rate of occurrence of a different irAE after a rechallenge. RESULTS A total of 24 079 irAE cases associated with at least 1 ICI were identified. Among the irAEs, 452 of 6123 irAEs associated with ICI rechallenges (7.4%) were informative rechallenges. One hundred thirty recurrences (28.8%; 95% CI, 24.8-33.1) of the initial irAE were observed. In a rechallenge, colitis (reporting odds ratio [OR], 1.77; 95% CI, 1.14-2.75; P = .01), hepatitis (reporting OR, 3.38; 95% CI, 1.31-8.74; P = .01), and pneumonitis (reporting OR, 2.26; 95% CI, 1.18-4.32; P = .01) were associated with a higher recurrence rate, whereas adrenal events were associated with a lower recurrence rate (reporting OR, 0.33; 95% CI, 0.13-0.86; P = .03) compared with other irAEs.CONCLUSIONS AND RELEVANCE This cohort study found a 28.8% recurrence rate of the same irAE associated with the discontinuation of ICI therapy after a rechallenge with the same ICI. Resuming ICI therapy could be considered for select patients, with appropriate monitoring and use of standard treatment algorithms to identify and treat toxic effects.

Aims  The risk and incidence of cardiovascular (CV) immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICIs) in cancer patients remain unknown. Methods and results We systematically reviewed all randomized clinical trials (RCTs) including at least one ICI-containing arm and available CV adverse event (CVAE) data in cancer patients in the ClinicalTrials.gov registry, Medline, and the Cochrane CENTRAL Register of Controlled Trials, up to 31 August 2020 (CRD42020165672). The primary outcome was the summary risk of 16 different CVAEs associated with ICI exposure vs. controls (placebo and non-placebo) in RCTs. CVAEs with an increased risk associated with ICI exposure were considered as CV irAEs. Summary incidences of CV irAEs identified in our primary outcome analyses were computed using all RCTs including at least one ICI-containing arm. We used a random-effects meta-analysis to obtain Peto odds ratios (ORs) with 95% confidence intervals (CIs) and logit transformation and inverse variance weighting to compute summary incidences. Sixty-three unique RCTs with at least one ICI-containing arm (32 518 patients) were retrieved, among which 48 (29 592 patients) had a control arm. Among the 16 CVAEs studied, ICI use was associated with an increased risk of 6 CV irAEs including myocarditis, pericardial diseases, heart failure, dyslipidemia, myocardial infarction, and cerebral arterial ischaemia with higher risks for myocarditis (Peto OR: 4.42, 95% CI: 1.56–12.50, P < 0.01; I2 = 0%, P = 0.93) and dyslipidemia (Peto OR: 3.68, 95% CI: 1.89–7.19, P < 0.01; I2 = 0%, P = 0.66). The incidence of these CVAEs ranged from 3.2 (95% CI 2.0–5.1) to 19.3 (6.7–54.1) per 1000 patients, in studies with a median follow-up ranging from 3.2 to 32.8 months. Conclusion In RCTs, ICI use was associated with six CV irAEs, not confined to myocarditis and pericarditis.

BackgroundSafety of rechallenge of immune checkpoint inhibitor (ICI) after grade ≥2 immune-related adverse events (irAEs) leading to ICI discontinuation remains unclear.MethodsAll adverse drug reactions involving at least one ICI reported up to December 31, 2019 were extracted from the French pharmacovigilance database. Patients were included if they experienced at least one grade ≥2 irAE resulting in ICI discontinuation, with subsequent ICI rechallenge. The primary outcome was the recurrence of at least one grade ≥2 irAE in these patients after ICI rechallenge.ResultsWe included 180 patients: 61.1% were men (median age of 66 years), 43.9% had melanoma and 78.9% were receiving anti-programmed cell death 1. First ICI discontinuation was related to 191 irAEs. After ICI rechallenge, 38.9% of the patients experienced at least one grade ≥2 irAE. Among them, 70.0% experienced the same irAE, 25.7% a distinct irAE, and 4.3% both the same and a distinct irAE. Lower recurrence rates of irAEs were associated with rechallenge with the same ICI treatment (p=0.02) or first endocrine irAEs (p=0.003). Gastrointestinal irAEs were more likely to recur (p=0.007). The median duration from ICI discontinuation to rechallenge and the severity of the initial irAE did not predict recurrent irAEs after ICI rechallenge (p=0.53 and p=0.40, respectively).ConclusionsIn this study, 61.1% of the patients who discontinued ICI treatment for grade ≥2 irAEs experienced no recurrent grade ≥2 irAEs after ICI rechallenge. Although ICI rechallenge appears to be safe under close monitoring, it should always be discussed balancing usefulness of rechallenge, patient comorbidities and risk of recurrence of first irAE(s). Due to inherent bias associated with pharmacovigilance studies, further prospective studies are needed to assess risk factors that may influence patient outcomes after ICI rechallenge.