A combination of immunotherapy drugs being tested by AstraZeneca in the third-line setting in patients with lung cancer has failed to slow disease progression or extend survival.

The Phase III ARCTIC trial (sub-study B) assessed the efficacy and safety of Imfinzi (durvalumab) plus tremelimumab, as well as Imfinzi and tremelimumab monotherapies, versus standard-of-care chemotherapy (SoC) in patients with PDL1-low/negative non-small cell lung cancer (NSCLC) who had received at least two prior treatments.

Top-line data show that the combination of Imfinzi plus tremelimumab in failed to show a statistically-significant and clinically-meaningful improvement in progression-free survival (PFS) and overall survival (OS) compared to SoC.

Sub-study A pitted Imfinzi monotherapy against SoC in patients with PDL1-high NSCLC. The trial was now not powered for statistical significance, but Imfinzi monotherapy did show a clinically-meaningful reduction in the risk of death compared to chemotherapy, AZ noted.

“While we are disappointed that the combination of Imfinzi plus tremelimumab did not result in a statistically-significant survival benefit in this heavily pre-treated patient population, we are encouraged by the activity of Imfinzi monotherapy observed in this trial and look forward to presenting the full data from the ARCTIC trial at an upcoming medical meeting,” said AZ’ chief medical officer Sean Bohen, commenting on the results.

Imfinzi was approved in the US in February for the treatment of patients with unresectable, Stage III NSCLC whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy, and is also under review in Europe.