Imfinzi is first immunotherapy to show both significant survival benefit and improved, durable responses in extensive-stage small cell lung cancer

AstraZeneca presented detailed results from the Phase III CASPIAN trial, showing Imfinzi (durvalumab) significantly improved overall survival (OS) in patients with previously-untreated extensive-stage small cell lung cancer (SCLC). Imfinzi in combination with four cycles of standard-of-care (SoC) chemotherapy (etoposide with either cisplatin or carboplatin) demonstrated a statistically-significant and clinically-meaningful improvement in OS vs. SoC consisting of up to six cycles of chemotherapy and optional prophylactic cranial irradiation (PCI).

The risk of death was reduced by 27% (equal to a hazard ratio of 0.73), with median OS of 13.0 months for Imfinzi plus chemotherapy vs. 10.3 months for SoC. Results showed a prolonged OS benefit with an estimated 33.9% of patients alive at 18 months following treatment with Imfinzi plus chemotherapy vs. 24.7% of patients following SoC. Across all efficacy endpoints, benefits were observed in patients treated with Imfinzi plus chemotherapy vs. SoC. Results showed a significantly higher progression-free survival (PFS) rate at 12 months (17.5% vs. 4.7%), a 10.3% increase in confirmed objective response rate (ORR) (67.9% vs. 57.6%), and improved duration of response (DOR) at 12 months (22.7% vs. 6.3%). The results were presented at the Presidential Symposium of the IASLC 2019 World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer in Barcelona, Spain.

Luis Paz-Ares, MD, Ph.D., Chair, Medical Oncology Department, Hospital Universitario Doce de Octubre, Madrid, Spain and principal investigator in the Phase III CASPIAN trial said: “Patients have had limited treatment options for small cell lung cancer, a devastating disease where the five-year survival rate has been as low as 6%. The significant survival benefit demonstrated with Imfinzi combined with only four cycles of a choice of chemotherapy compared to a robust control arm, provides evidence and hope of a new treatment option for these patients".

The safety and tolerability of Imfinzi in combination with SoC etoposide and platinum-based chemotherapy was consistent with previous trials. Results showed that 61.5% of patients experienced a Grade 3 or 4 AE with Imfinzi plus SoC (all causes) vs. 62.4% with SoC, and patients discontinuing treatment due to AEs were similar between arms (9.4% vs. 9.4%). Imfinzi is also being tested following concurrent chemoradiation therapy in limited-stage SCLC in the Phase III ADRIATIC trial.

Comment: Imfinzi is approved in the curative-intent setting of unresectable, Stage III non-small cell lung cancer after chemoradiotherapy in 49 countries, including the US, Japan and across the EU, based on the Phase III PACIFIC trial.