Imfinzi shows sustained OS benefit in first-line ES-SCLC in CASPIAN trial

Detailed results from an updated analysis of the Phase III CASPIAN trial showed AstraZeneca’s Imfinzi (durvalumab) in combination with a choice of chemotherapies, etoposide plus either carboplatin or cisplatin, demonstrated a sustained, clinically meaningful overall survival (OS) benefit for adults with extensive-stage small cell lung cancer (ES-SCLC) treated in the 1st-line setting.

The CASPIAN trial met the primary endpoint of OS in June 2019, reducing the risk of death by 27% (based on a hazard ratio [HR] of 0.73; 95% confidence interval [CI] 0.59-0.91; p=0.0047) which formed the basis of the US FDA approval in March 2020.

After a median follow up of more than two years, the latest results for Imfinzi plus chemotherapy showed sustained efficacy, maintaining a 25% reduction in the risk of death versus chemotherapy alone (based on an HR of 0.75; 95% CI 0.62, 0.91; nominal p=0.0032). Updated median OS was 12.9 months versus 10.5 for chemotherapy. In a post-hoc analysis, an estimated 22.2% of patients treated with Imfinzi plus chemotherapy were alive at 24 months versus 14.4% for chemotherapy.

For Imfinzi plus chemotherapy, 11% of patients were alive and progression-free at 24 months versus 2.9% for chemotherapy alone (post-hoc). Imfinzi plus chemotherapy maintained a high confirmed objective response rate (ORR) (68% versus 58%) and in a post-hoc analysis, duration of response (DoR) for Imfinzi at 24 months was 13.5% versus 3.9% for chemotherapy. At 24 months, 12% of patients in the Imfinzi plus chemotherapy arm remained on Imfinzi treatment.

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: “These updated results from the CASPIAN trial show a remarkable 22% of patients still alive at 24 months, supporting the sustained benefits of treatment with Imfinzi plus chemotherapy. This is an effective 1st-line treatment in the extensive-stage setting, where improving outcomes has been a challenge and so few patients survive five years.”

José Baselga, Executive Vice President, Oncology R&D, said: “After two years median follow-up, Imfinzi continues to show sustained and meaningful improvements in survival and prolonged treatment response for patients facing this devastating and aggressive disease. These data reinforce Imfinzi plus chemotherapy as an important new standard of care for extensive-stage small cell lung cancer patients, and this regimen offers patients convenient dosing every four weeks during maintenance. We look forward to bringing the benefits of Imfinzi to patients around the world.”

The second experimental arm in the CASPIAN trial testing tremelimumab, an anti-CTLA4 monoclonal antibody, added to Imfinzi and chemotherapy showed a trend towards OS, but did not reach statistical significance compared to chemotherapy alone.

The safety and tolerability for Imfinzi plus chemotherapy was consistent with the known safety profile of these medicines. Results showed 62.3% of patients experienced a Grade 3 or 4 adverse event with Imfinzi plus chemotherapy (all causes) versus 62.8% with chemotherapy alone. The percentage of patients discontinuing treatment (all causes) was 10.2% for Imfinzi plus chemotherapy and 9.4% for chemotherapy alone.

Imfinzi in combination with etoposide and either carboplatin or cisplatin is currently under regulatory review for the treatment of ES-SCLC in the 1st-line setting in the EU and Japan.

Updated results from the CASPIAN trial were presented during the 2020 American Society of Clinical Oncology ASCO20 Virtual Scientific Program on 29 to 31 May 2020. Several presentations featured during the meeting will showcase AstraZeneca’s leadership in lung cancer across early and late-stage disease and reinforce the Company’s biomarker-driven approach.