Interim analysis of a Phase 3 trial shows that treatment with Imfinzi (durvalumab) extends the survival of patients with advanced, inoperable non-small cell lung cancer (NSCLC), according to AstraZeneca and its research and development subsidiary, MedImmune.
The randomized, double-blind, multicenter PACIFIC Phase 3 trial (NCT02125461) is testing Imfinzi versus placebo in patients with inoperable, stage 3 — or locally advanced — NSCLC whose disease had not progressed after standard platinum-based chemoradiation therapy.
Stage 3 NSCLC represents about one-third of NSCLC cases, most of which are inoperable, or unresectable. The trial involves 713 patients across 26 countries.
The independent interim analysis revealed that, compared with placebo, treatment with Imfinzi significantly increased patients’ overall survival, one of the trial’s two main goals, a result that was both statistically significant and clinically meaningful.
In May 2017, AstraZeneca reported that Imfinzi met its first goal, improving progression-free survival (PFS) by 11.2 months. PFS refers to the length of time during or after treatment without cancer progression or death.
Safety and tolerability results matched those reported at the time of the PFS analysis. The scientists are also addressing overall response rate — the number of patients with tumor size reduction over a predefined amount of time — and duration of response. AstraZeneca expects to present trial results at an upcoming medical meeting.
“The readout of positive overall survival data at the interim analysis of the PACIFIC trial provides additional compelling evidence of the clinical benefit that Imfinzi can offer patients in this earlier stage of lung cancer,” Sean Bohen, MD, PhD, executive vice president of global medicines development and chief medical officer at AstraZeneca, said in a press release.
“We look forward to sharing these results with Health Authorities to support ongoing regulatory interactions and to update the Imfinzi label,” he said.
Imfinzi is a human antibody that binds to the PD-L1 protein found on the surface of cancer cells and blocks its interaction with two molecules, PD-1 and CD80, preventing the tumor from evading attack from the immune system.
The medication has recently been approved in the U.S. and Canada for the treatment of patients with advanced, inoperable, and stabilized stage 3 NSCLC, based on PACIFIC data. Imfinzi is also under regulatory review in the EU, Japan, and other countries, with decisions expected by the second half of 2018.
AstraZeneca focuses on different forms, stages, and lines of therapy for lung cancer. Imfinzi is being tested both as a monotherapy, and in combination with the immune checkpoint inhibitor tremelimumab and/or chemotherapy. Combinations of Imfinzi with radiation therapy and small molecules are also being assessed in patients with locally advanced or metastatic urothelial carcinoma and head and neck cancer, among other tumor types.
The company has two approved medications — Iressa (gefitinib) and Tagrisso (osimertinib) — for NSCLC patients with EGFR-mutated tumors. AstraZeneca’s late-stage program also addresses the 75-80 percent of lung cancer patients without a known genetic mutation.