Immune-Mediated Adverse Events With Concomitant Radiotherapy and Immunotherapy
Posted: Tuesday, July 7, 2020
According to research from an evolving retrospective registry, presented during the ASCO20 Virtual Scientific Program (Abstract 3144), patients with Merkel cell carcinoma or melanoma who underwent concomitant radiotherapy and checkpoint inhibitor therapy may be more likely to develop immune-mediated adverse events. The combination treatment has previously been identified to boost immune-mediated responses against tumor antigens.
“Almost half of patients developed new immune-mediated adverse events following radiotherapy, with 25% (4/16) of cases warranting hospitalization; these incidence rates appear to exceed rates from historical data and raise concerns about the additive toxicity of[checkpoint inhibitors and radiotherapy,” concluded Nikolaos Andreatos, MD, of the Cleveland Clinic, and colleagues.
The study screened 731 patients with Merkel cell carcinoma or melanoma who underwent radiotherapy within 30 days of receiving checkpoint inhibitor therapy. A total of 35 patients were identified, 5 of whom had Merkel cell carcinoma and 30 of whom had melanoma. A total of 16 patients (45.7%) experienced immune-mediated adverse events, 9 of whom developed those reactions within 1 month of radiotherapy. Immune-mediated adverse events grade 3 or higher resulted in hospitalization for four patients and death for one after development of pneumonia-related respiratory failure. An association was noted between increased immune-mediated adverse events and ipilimumab/nivolumab treatment (P = .27).
The most commonly used treatment consisted of PD-1 inhibitors (22 radiation periods), followed by ipilimumab/nivolumab (14 radiation periods), ipilimumab (4 radiation periods), and avelumab (3 radiation periods). Concurrent checkpoint inhibitor therapy and radiotherapy were given in 32 radiation periods, whereas sequential treatment was given in 11 radiation periods. Intracranial radiation included 14 radiation periods.
According to the investigators, comparison of findings to nonradiotherapy cohorts as well as survival analyses are ongoing.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
