Overall Survival From Tebentafusp Versus Nivolumab Plus Ipilimumab in First Line Metastatic Uveal Melanoma: A Propensity Score Weighted Analysis

Abstract

Background

Tebentafusp demonstrated a superior overall survival (OS) benefit (hazard ratio [HR] 0.51) compared to investigator's choice (82% pembrolizumab) in a randomized, Phase 3 trial (IMCgp100-202; N=378) in untreated metastatic uveal melanoma (mUM). The 1-year OS rates for tebentafusp and pembrolizumab were 73% and 59%, respectively. In the single-arm GEM1402 (N=52), the 1-year OS rate for nivolumab plus ipilimumab (N+I) in mUM was 52%. Due to limitations in conducting randomized trials in mUM, we compared OS on tebentafusp or pembrolizumab (IMCgp100-202) to nivolumab plus ipilimumab (GEM1402) in untreated mUM using propensity scoring methods.

Patients and methods

Analyses were adjusted using propensity score-based inverse probability of treatment weighting (IPTW), balancing age, gender, baseline lactate dehydrogenase (LDH), baseline alkaline phosphatase, disease location, ECOG status, and time from primary diagnosis to metastasis. OS was assessed using IPT weighted Kaplan-Meier and Cox proportional hazard models. Sensitivity analyses using alternative missing data and weights methods were conducted.

Results

The primary IPTW analysis included 240 of 252 patients randomized to tebentafusp from IMCgp100-202 and 45 of 52 nivolumab plus ipilimumab-treated patients from GEM-1402. Key baseline covariates, including LDH were generally well balanced prior to weighting. The IPTW-adjusted OS favored tebentafusp, HR 0.52 (95% confidence interval [CI]: 0.35, 0.78); 1-year OS was 73% for tebentafusp vs 50% for N+I. Sensitivity analyses showed consistent superior OS for tebentafusp with all IPTW HRs ≤0.61. IPTW analysis of pembrolizumab versus N+I showed no significant difference in OS (HR 0.72; 95% CI: 0.50, 1.06).

Conclusion

Tebentafusp was previously shown to provide an OS benefit compared to checkpoint inhibitors or chemotherapy in untreated mUM. Propensity score analysis demonstrated a similar OS benefit for tebentafusp compared with N+I. These data further support tebentafusp as the standard of care in previously untreated HLA-A*02:01+ adult patients with mUM.