Jeffery S. Weber, MD, PhD

Nivolumab (Opdivo) and ipilimumab (Yervoy) have demonstrated considerable success in the field of metastatic melanoma as both single agents and in combination. However, questions remain regarding sequencing the agents and the high toxicities that often occur when the 2 immunotherapies are used together.

To explore these challenges, OncLive spoke with Jeffery S. Weber, MD, PhD, deputy director of the Laura and Isaac Perlmutter Cancer Center, co-director of the Melanoma Program, and head of Experimental Therapeutics at NYU Langone Medical Center.

Weber discusses findings from the phase II CheckMate-064 trial, in which patients were randomized to receive either nivolumab followed by ipilimumab followed by nivolumab maintenance therapy, or ipilimumab followed by nivolumab and maintenance therapy with nivolumab. He also places the results from this sequential study in the context of findings from the phase II CheckMate-069 trial, which examined the combination of nivolumab and ipilimumab in patients with advanced melanoma.

OncLive: Could you describe the goals and design of the CheckMate-064 trial?

Weber: CheckMate-064 was a trial that was written by F. Stephen Hodi, MD, of Dana-Farber Cancer Institute, and myself, which became a Bristol-Myers Squibb–sponsored trial, that ultimately evolved to a randomized phase II trial. This was a trial in which 140 patients were randomly allocated to receive sequential immunotherapy. This means that patients were randomized 1:1 to receive 12 weeks of induction nivolumab in what we called cohort A, followed by a forced switch to 12 weeks of ipilimumab and then maintenance nivolumab every other week at 3 mg/kg until progression, toxicity, or refusal.

In cohort B, the opposite sequence was given: 12 weeks of ipilimumab at the standard dose at a schedule of 3 mg/kg every 3 weeks for 12 weeks and then a forced switch to 12 weeks of nivolumab and then maintenance nivolumab until progression, toxicity, or refusal. Cohorts A and B varied only in the reversal of the sequence, the total treatment would have been the same in either cohort; the timing was just different.

The primary endpoint was grade 3, 4, and 5 adverse events (AEs) by the end of the second induction cycle at week 25. Secondary endpoints included response rate, PFS, and a variety of biomarker studies. It was also a very important biomarker study. Patients on this trial predominantly have leukapheresis at time 0, after the first cycle at week 13, and after the second induction cycle at week 25. We had biopsies before and after in a fair number of patients.

The exploratory endpoint also included survival comparisons between the arms. The demographics showed that while there was a fairly good balance between the 2 arms, there was actually an imbalance in the PS1 patients who favored cohort A. There was also a slight imbalance in patients who had brain metastases that went the other way. There was also what appeared to be a significant imbalance in the PD-L1 population. There were more PD-L1–positive patients by the 5% in cohort A than cohort B. Therefore, there were 2 prognostic factors that appeared to favor arm A—but one that appeared to favor arm B—which was fewer patients with brain metastases.

The eligibility was very straightforward. You could have failed a systemic therapy, but you could not have had a previous PD-1/PD-L1 antibody or a CTLA-4 antibody. Most of the patients were treatment-naïve, but a good proportion of them had 1 prior systemic regimen. If you had brain metastases, you had to have them treated and be stable for at least 4 weeks. It was a metastatic cohort that one would see in any registration study, with the exception of that slight imbalance between the arms.

What were the findings regarding toxicity?

In the first induction cycle, there were no surprises as they were only receiving 1 drug. There was a 7% grade 3/4 AE rate in the nivolumab arm and about a 20% grade 3/4 AE rate in cohort B that received ipilimumab.

The surprise was that, by week 25, we actually saw more toxicity in cohort A at about 50% versus about 42% in cohort B. That is getting up to the rates that we are seeing with concurrent therapy. Please be reminded that the reason we did the trial was to try and achieve equal efficacy of concurrent therapy by sequencing the drugs to lower the toxicity.