The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Administering adjuvant ipilimumab may improve overall survival in patients with resected high-risk melanoma, according to the findings of a randomized phase 3 trial presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

In the study (ClinicalTrials.gov identifier: NCT01274338), 523 patients were randomized to receive ipilimumab 3 mg/kg, 636 were randomized to receive high-dose interferon-α2b, and 511 were randomized to receive ipilimumab 10 mg/kg. Patients in the first group received induction low-dose ipilimumab every 3 weeks for a total of 4 courses followed by maintenance low-dose ipilimumab every three months for a maximum of 4 courses. Patients in the second group received high-dose interferon-α2b for 1 month followed by maintenance high-dose interferon-α2b, 3 times per week for 11 months. Patients in the third group received induction high-dose ipilimumab every 3 weeks for a total of 4 courses followed by maintenance high-dose ipilimumab every 3 months for a maximum of 4 courses. The researchers evaluated each type of treatment for safety and efficacy. Primary end points were overall survival and relapse-free survival.

When the researchers compared overall survival in ipilimumab 3 mg/kg group with the high-dose interferon-α2b group, they found that ipilimumab 3 mg/kg yielded better results; 5-year overall survival was 0.72 (95% CI, 0.68-0.76) in the low-dose ipilimumab group compared with 0.67 (95% CI, 0.62-0.72) in the other group.

When the investigators compared overall survival in the ipilimumab 10mg/kg group with the high-dose interferon-α2b group, they identified a trend toward improvement in overall survival in the ipilimumab 10 mg/kg group but those trends were not statistically significant.

When the researchers compared relapse-free survival (RFS) in the ipilimumab 3 mg/kg group with the high-dose interferon-α2b group, they found that median RFS in the ipilimumab group was 4.5 years compared with 2.5 years in the other group. In a comparison between higher-dose ipilimumab and high-dose interferon-α2b group, there was a trend toward improvement in the ipilimumab group but it was not statistically significant.

The researchers found that 37% of patients who received ipilimumab 3 mg/kg experienced grade 3 or higher adverse events compared with 79% of patients who received high-dose interferon-α2b and 58% of patients who received ipilimumab 10 mg/kg. In addition, 35% of patients who received ipilimumab 3 mg/kg experienced adverse events of any grade that led to discontinuation of treatment compared with 20% of patients who received high-dose interferon-α2b and 54% of those who received ipilimumab 10 mg/kg. Of all grade 5 adverse events that were at least possibly related to treatment, 3 occurred in the ipilimumab 3 mg/kg (ipi3) group, 2 occurred in the high-dose interferon-α2b group, and 8 occurred in the ipilimumab 10 mg/kg group.

“For the first time in the adjuvant therapy of melanoma, E1609 has demonstrated significant improvement of overall survival with ipi3 against an active control regimen previously shown to have both [overall survival] and [relapse-free survival] benefits,” said lead study author Ahmad A. Tarhini, MD, PhD, acting professor in the department of hematology and medical oncology at Emory University School of Medicine, Atlanta.

Read more of Cancer Therapy Advisor‘s coverage of ASCO’s annual meeting by visiting the conference page.

Reference

Tarhini AA, Lee SJ, Hodi FS, et al. United States Intergroup E1609: A phase III randomized study of adjuvant ipilimumab (3 or 10 mg/kg) versus high-dose interferon-α2b for resected high-risk melanoma. Presented at: 2019 American Society of Clinical Oncology (ASCO) Annual Meeting; May 31-June 4, 2019; Chicago, IL. Abstract 9504.