CheckMate 511 trial

Background

Phase III RCT of 360 treatment-naïve patients with unresectable stage III or IV melanoma, designed to test whether a lower ipilimumab dose reduces toxicity while preserving efficacy of the nivolumab plus ipilimumab combination.

Interventions and follow up

Arm A: nivolumab 3mg/kg + ipilimumab 1mg/kg q3wk x4, then nivolumab 480mg q4wk until progression or unacceptable toxicity
Arm B: nivolumab 1mg/kg + ipilimumab 3mg/kg q3wk x4, then nivolumab 480mg q4wk until progression or unacceptable toxicity
Primary endpoint: incidence of treatment-related grade 3-5 adverse events
Minimum follow up: 12mo

Results

Grade 3-5 treatment-related AEs (primary): 34% vs 48%, P=.006 (A vs B)
mPFS: 9.9mo vs 8.9mo; HR 1.06, 95%CI 0.79-1.42
mOS: not reached in either arm; HR 1.09, 95%CI 0.73-1.62
ORR: 45.6% vs 50.6%, P=.35

Adverse events

Grade 3-5 treatment-related AEs: 33.9% (NIVO3+IPI1) vs 48.3% (NIVO1+IPI3)
Pattern: lower IPI dose reduced overall and immune-related toxicity while preserving efficacy endpoints
Treatment-related deaths: rare in both arms

Conclusions

NIVO3+IPI1 significantly reduced grade 3-5 toxicity versus NIVO1+IPI3 in unresectable stage III/IV melanoma, with no apparent loss of efficacy on descriptive comparison.

Key Limitations

Powered for safety, not efficacy; efficacy comparisons are descriptive and underpowered; relatively short follow-up; cannot exclude clinically meaningful efficacy differences.

Clinical Context

Provides rationale for lower-dose ipilimumab schedules to improve tolerability of dual checkpoint blockade; informs ASCO and ESMO discussion of dosing strategies in advanced melanoma.

References