According to multiple media reports, AstraZeneca’s investigational lung cancer therapy — a combination of the checkpoint inhibitor Imfinzi and the CTLA-4 inhibitor tremelimumab — missed a key primary endpoint in a Phase 3 “MYSTIC” trial for first-line NSCLC lung cancer patients.

The phase 3 test was seeking to boost progression-free survival (PFS) in advanced, first-line non-small cell lung cancer patients using either its PD-L1 checkpoint inhibitor Imfinzi (durvalumab) as a monotherapy, or Imfinzi in combo with CTLA-4 drug tremelimumab.

The medications were pitted against platinum-based standard-of-care, but after much speculation the British-based drugmaker said it had failed to improve PFS when compared to chemo in patients whose tumors express PD-L1 on 25% or more of their cancer cells.