Imfinzi Phase III MYSTIC study disappoints

Shares of AstraZeneca (LSE AZN) were down 2.93% at £61.32 by 11,16 am, after the Anglo-Swedish pharma major revealed that its Imfinzi (durvalumab) did not meet the main goal of improving survival rates for patients with the most advanced form of lung cancer.

Along with its biologics R&D unit MedImmune, AstraZeneca today announced final overall survival (OS) results for the Phase III MYSTIC trial, a randomized, open-label, multicenter, global trial of Imfinzi monotherapy and the combination of Imfinzi and tremelimumab, an anti-CTLA4 antibody, versus standard-of-care (SoC) platinum-based chemotherapy in previously-untreated patients with Stage IV (metastatic) non-small cell lung cancer (NSCLC).

In the primary analysis population of patients, whose tumours express PD-L1 on 25% or more of their cancer cells as determined by the VENTANA PD did not meet the primary endpoints of i-L1 (SP263) Assay, Imfinzi monotherapy and the combination of Imfinzi plus tremelimumab improving OS compared to SoC chemotherapy. While the OS result did not meet statistical significance, a hazard ratio (HR) of 0.76 (97.54% CI 0.564-1.019; nominal p=0.036) was observed with Imfinzi monotherapy. The combination therapy had an HR of 0.85 (98.77% CI 0.611-1.173; nominal p=0.202); the data support further analysis in exploratory subgroups.