Updated Findings Confirm Long-Term Survival Benefit with Durvalumab in NSCLC

David R. Spigel, MD

Long-term treatment with durvalumab (Imfinzi) following chemoradiation was associated with robust and sustained overall survival (OS) and progression-free survival (PFS) benefits in patients with unresectable stage III non-small cell lung cancer (NSCLC) whose disease had not progressed after platinum-based concurrent chemoradiotherapy, according to 5-year follow-up data from the phase 3 PACIFIC (NCT02125461) trial.

“(These study results establish) a new benchmark for the standard of care in the unresectable stage III non-small-cell lung cancer setting,” said lead study author David R. Spigel, MD, of the Sarah Cannon Cancer Institute, while presenting the findings during the 2021 ASCO Annual Meeting.

Earlier data from the phase 3 PACIFIC trial, which were previously announced in 2018, demonstrated how treatment with durvalumab significantly improved OS versus placebo among patients.

The trial comprised 713 patients randomized 2:1 to receive either study drug (n = 476) at 10 mg/kg q2w or placebo (n = 237) q2w for up to 12 months.

Eligible patients must have had unresectable stage 3 NSCLC without progression after definitive platinum-based cCRT (≤2 cycles), a WHO PS score of 0 or 1, archived pre-cCRT tumor tissue for PD-L1 testing (if available) and been 18 years or older. PD-L1 enrollment status was not required for enrollment in the trial.

Here, Spigel and colleagues presented 5-year updated data from the randomized, double-blind trial. The OS and PFS outcomes were assessed approximately 5 years after the last patient was randomized. Data cutoff was January 11, 2021.

At a median follow-up of 34.2 months, updated median 5-year OS was 47.5 months in the arm that received durvalumab and 29.1 months in those who received placebo (HR = 0.72; 95% CI, 0.59-0.89). Moreover, median 5-year PFS in the durvalumab arm was 16.9 months and 5.6 months in the placebo arm (HR = 0.55; 95% CI, 0.45-0.68).

Of note, an estimated 42.9% of patients randomized to durvalumab remain alive at 5 years as opposed to 33.4% of patients who received a placebo. And approximately 33.1% of durvalumab-treated patients remain alive without disease progression compared to 19% of the placebo group.

The last patient completed treatment in May 2017. Since then, 58.8% of randomized patients died (55.5% who had received durvalumab and 65.4% who had received the placebo).

Spigel concluded noting that the regimen from the PACIFIC trial is being investigated in combination with other chemoradiotherapy regimens as well as other agents following chemoradiotherapy.

Reference

Spigel DR, Faivre-Finn C, Elaine Gray J, et al. Five-year survival outcomes with durvalumab after chemoradiotherapy in unresectable stage III NSCLC: An update from the PACIFIC trial. J Clin Oncol. 2021;39 (suppl 15): Abstract 8511.