AstraZeneca’s Imfinzi fails to improve OS in Mystic lung cancer trial

The company has reported the final OS results for the phase III Mystic trial, which is a study of Imfinzi monotherapy and the combination of Imfinzi and anti-CTLA4 antibody tremelimumab against standard-of-care (SoC) platinum-based chemotherapy in previously-untreated patients with stage IV (metastatic) non-small cell lung cancer (NSCLC).

Imfinzi is a human monoclonal antibody, which binds to PD-L1 and blocks the interaction of PD-L1 with PD-1 and CD80.

Imfinzi monotherapy and the combination of Imfinzi plus tremelimumab have failed to achieve the primary endpoints of improving OS compared to SoC chemotherapy in the primary analysis population of patients.

Based on the phase III Pacific trial, Imfinzi secured approval to treat unresectable and stage III NSCLC in over 40 countries, including the US, EU and Japan.

The Mystic trial is a randomized, open-label, multi-center and global phase III trial of Imfinzi monotherapy or Imfinzi in combination with tremelimumab against SoC chemotherapy in the first-line treatment of patients with epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) wild-type, locally-advanced or metastatic (stage IV) NSCLC.

The trial was carried out in 167 centers across 17 countries, including the US, Canada, Europe, Russia, Australia and parts of Asia, including Japan, Korea, Thailand, Taiwan and Vietnam.

The primary endpoints of the trial are progression-free survival (PFS) for the combination, and OS in monotherapy and in combination therapy.

In July 2017, the company announced that the combination of Imfinzi and tremelimumab failed to achieve the primary endpoint of improving PFS compared against SoC.

AstraZeneca global medicines development executive vice president and chief medical officer Sean Bohen said: “We are encouraged to see that Imfinzi monotherapy activity is in-line with that of the anti-PD-1 class in previously-untreated patients with Stage IV non-small cell lung cancer; however, we are disappointed that these results missed statistical significance.

“We remain confident in Imfinzi as the cornerstone of our IO programme and continue to evaluate its potential in ongoing non-small cell lung cancer trials, including Imfinzi and Imfinzi plus tremelimumab in combination with chemotherapy.”