Hyperprogressive disease in early‐phase immunotherapy trials: Clinical predictors and association with immune‐related toxicities

BACKGROUND: A subset of patients treated with immune checkpoint inhibitors experience an accelerated tumor growth rate (TGR) in comparison with pretreatment kinetics; this is known as hyperprogression. This study assessed the relation between hyperprogressive disease (HPD) and treatment-related toxicity and clinical factors. METHODS: This study reviewed patients with solid tumors who were enrolled in early-phase immunotherapy trials at Princess Margaret Cancer Centre between August 2012 and September 2016 and had computed tomography scans in the pre-immunotherapy (reference) and on-immunotherapy (experimental) periods. HPD was defined as progression according to Response Evaluation Criteria in Solid Tumors 1.1 at the first on-treatment scan and a ≥2-fold increase in TGR between the reference and experimental periods. Treatment-related toxicities requiring systemic therapy, drug delays, or discontinuation were considered clinically significant adverse events (CSAEs). RESULTS: Of 352 patients, 182 were eligible for analysis. The median age was 60 years, and 54% were male. The Eastern Cooperative Oncology Group performance status was 0 (32%) or 1 (68%). The Royal Marsden Hospital (RMH) prognostic score was 0/1 in 59%. Single-agent immunotherapy was given to 80% of the patients. Most patients (89%) received anti-programmed death (ligand) 1 antibodies alone or in combination with other therapies. HPD occurred in 12 of 182 patients (7%). A higher proportion of females was seen among HPD patients (P = .01), but no association with age, performance status, tumor type, RMH prognostic score, combination immunotherapy, or CSAEs was found. The 1-year overall survival rate was 28% for HPD patients and 53% for non-HPD patients (hazard ratio, 1.7; 95% confidence interval, 0.9-3.3; P = .11). CONCLUSIONS: HPD was observed in 7% of patients with solid tumors treated with immunotherapy. HPD was not associated with CSAEs, age, tumor type, or the type of immunotherapy but was more common in females.