AstraZeneca has reported that a combination of its drug Imfinzi (durvalumab) with chemotherapy improved progression-free survival (PFS) in the ongoing Phase III POSEIDON clinical trial involving treatment-naïve patients with stage IV non-small cell lung cancer (NSCLC).

Imfinzi is a human monoclonal antibody designed to inhibit the interaction of PD-L1 with PD-1 and CD80. It has regulatory approval to treat unresectable, stage III NSCLC.

The drug is also indicated in 11 countries for previously treated advanced bladder cancer patients.

In the open-label, randomised, multi-centre POSEIDON trial, Imfinzi is being tested in combination with platinum-based chemotherapy, as well as with tremelimumab plus chemotherapy as a first-line treatment.

The trial is being conducted at 153 sites in 18 countries and compared the combination therapy to chemotherapy alone. Its primary endpoints for the Imfinzi and chemotherapy combination are PFS and overall survival (OS).

Key secondary endpoints include PFS and OS for the triple combination.

The primary endpoint has been met with statistically significant and clinically meaningful improvement in PFS when treated with Imfinzi plus a choice of five platinum-based chemotherapies versus chemotherapy alone.

Similar improvements were observed with the Imfinzi plus tremelimumab and chemotherapy combination.

The safety and tolerability of AstraZeneca’s drug were consistent with its known safety profile.

The triple combination also demonstrated a safety profile similar to that of the Imfinzi and chemotherapy combination, without any increase in treatment discontinuation.

AstraZeneca Oncology R&D executive vice-president José Baselga said: “Clinical benefit was observed in a trial population that included a high proportion of patients with squamous disease and multiple choices of chemotherapy regimens.

“Additionally, the potential to add tremelimumab to Imfinzi and chemotherapy may present an important treatment approach in this challenging setting, especially taking into consideration the favourable safety profile.”

The trial will further evaluate the additional primary endpoint of OS and data is expected next year.

AstraZeneca’s drug is also undergoing a separate Phase III trial, PEARL, as monotherapy in stage IV NSCLC patients.