Overall, 35% of patients in the combination arm and 70% in the monotherapy arm received any subsequent therapy. Altogether 64% of patients randomized to ipilimumab crossed over to receive any systemic therapy at the time of progression. Eighteen percent of patients in the combination group received subsequent anti-PD-1 therapy at progression, compared with 62% in the ipilimumab monotherapy arm. The median time to initiation of the subsequent therapy was not reached in the combination arm and was 6.1 months in the ipilimumab alone arm.
When assessing efficacy of combination immunotherapy by PD-L1 status, there was no difference in the ORR at the 1-month data cut, and no difference in PFS or OS at 2 years between patients who were defined as PD-L1-positive versus those defined as PD-L1-negative.
Treatment-related adverse events were consistent with the initial reports, with higher rates of gastrointestinal and hepatic adverse events of any grade with the combination compared with monotherapy.
Grade 3/4 treatment-related AEs occurred in 54% of patients treated with the combination regimen versus 20% with ipilimumab alone. AEs led to discontinuation in 37% of patients treated with the combination regimen compared with 9% for ipilimumab alone.
Further information on survival outcomes with nivolumab plus ipilimumab are expected from the larger randomized phase III CheckMate-067 trial, said Postow. Initial findings from this study were reported at the 2015 ASCO Annual Meeting.
Postow MA, Chesney J, Pavlick AC, et al Initial report of overall survival rates from a randomized phase II trial evaluating the combination of nivolumab (NIVO) and ipilimumab (IPI) in patients with advanced melanoma (MEL). Presented at: AACR 2016, New Orleans; April 16-20, 201. Abstract CT002.
Postow MA, Chesney J, Pavlick AC, et al. Nivolumab and ipilimumab versus ipilimumab in untreated melanoma. N Engl J Med 2015;372
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