New Zealand national retrospective cohort study of survival outcomes of patients with metastatic melanoma receiving immune-checkpoint inhibitors.

BACKGROUND

Immune checkpoint inhibitors (ICIs) have increased overall survival (OS) in metastatic melanoma in all clinical trials to date. However, pivotal trial populations were not representative of the real-world population in New Zealand. Real-world treatment effectiveness studies help evaluate the value of public pharmaceutical expenditure.

AIM: To determine the survival outcomes of New Zealand patients with unresectable or metastatic melanoma treated with pembrolizumab or nivolumab.

METHODS

This is a national retrospective cohort study. Patients with advanced unresectable or metastatic melanoma who received publicly funded immune-checkpoint inhibitors (ICIs) from 2017 to 2019 were included. Individual patient data were extracted from national administrative databases. The primary endpoint was OS, and secondary endpoints included OS by age, duration of treatment, posttreatment survival, and 30-day mortality from last pharmaceutical claim.

RESULTS

Five hundred ninety-seven patients were included, with a median follow-up of 25 months. One-year OS was 72%, the 2-year OS estimate was 60%, and median OS not reached. Survival did not differ by dichotomized age (≥70 vs. <70 year old), hazard ratio (HR) .94 (95% confidence interval (CI): .72-1.22; p = .62). Median duration of treatment was 9.0 months (95% CI: 7.9-10.1). Median post-treatment survival for the subgroup who had ceased treatment was 12.0 months (95% CI: 9.0-14.0). For the sample as a whole, the estimated 30-day mortality from last pharmaceutical claim was 15.7%.

CONCLUSION

OS in our New Zealand real-world population is comparable to pivotal clinical trials and real-world data (RWD) from other countries. These findings support the achievement of health gains from use of ICI in advanced unresectable and metastatic melanoma.