Posted: Friday, June 14, 2024
Adding the Toll-like receptor 9 agonist tilsotolimod to the CTLA-4 inhibitor ipilimumab did not improve response or overall survival in patients with PD-1–refractory advanced melanoma, according to the results of the phase III ILLUMINATE-301 clinical trial. Adi Diab, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues presented their findings at the 2024 American Society for Clinical Oncology (ASCO) Annual Meeting (Abstract LBA9516), noting the results represent the largest prospective data set on the use of ipilimumab in this setting to date.
A total of 481 patients with unresectable stage III to IV melanoma that progressed during or after anti–PD-1 therapy were included in the study. Participants were randomly assigned to receive 24 weeks of tilsotolimod plus ipilimumab (n = 238) or 10 weeks of ipilimumab alone (n = 243). Intravenous ipilimumab (3 mg/kg) was administered every 3 weeks, beginning in the first week for participants receiving ipilimumab alone, and in the second week for those receiving the combination therapy. A total of nine intratumoral injections of tilsotolimod were administered to a single designated lesion over 24 weeks.
The investigators reported objective response rates of 8.8% among patients who received tilsotolimod and 8.6% among those who received ipilimumab alone, with disease control rates of 34.5% and 27.2%, respectively. In addition, median overall survival was 11.6 months among those who received tilsotolimod and 10 months among those who received ipilimumab alone (hazard ratio = 0.96; 95% confidence interval = 0.77–1.19; P = .7). Finally, grade 3 or higher treatment-emergent adverse events were reported in 61.1% and 55.5% of patients in each group, respectively.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.