AstraZeneca’s Imfinzi (durvalumab) has been approved in Japan for the treatment of patients with extensive-stage small cell lung cancer (ES-SCLC), in combination with etoposide plus a choice of platinum chemotherapy (either carboplatin or cisplatin). SCLC is a highly aggressive, fast-growing form of lung cancer that typically recurs and progresses rapidly, despite initial response to chemotherapy.1,2

The approval by the Japanese Ministry of Health, Labour and Welfare was based on positive results from the Phase III CASPIAN trial, showing Imfinzi plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS) versus chemotherapy alone. These results were published in The Lancet in 2019.3

Makoto Nishio MD, PhD, Director, Thoracic Medical Oncology, The Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan and an investigator in the Phase III CASPIAN trial, said: “Patients with extensive-stage small cell lung cancer in Japan are in urgent need of new options that can provide long-term tumour control and sustained improvements in overall survival. This approval of Imfinzi provides Japanese patients with a new, effective and well-tolerated 1st-line treatment option for this disease, and for the first time physicians have the opportunity to combine immunotherapy with cisplatin for these patients.”

Dave Fredrickson, Executive Vice President, Oncology Business Unit, said: “This approval of Imfinzi provides an important new immunotherapy option in Japan for patients with extensive-stage small cell lung cancer. These patients have an especially poor prognosis, with only two per cent surviving beyond five years. Imfinzi, in combination with chemotherapy, delivers a sustained survival benefit and prolonged treatment response with a convenient dosing regimen given every four weeks during maintenance.”

The CASPIAN trial met the primary endpoint of OS for Imfinzi plus chemotherapy in June 2019, reducing the risk of death by 27% versus chemotherapy alone (based on a hazard ratio [HR] of 0.73; 95% confidence interval [CI] 0.59-0.91; p=0.0047), with median OS of 13.0 months versus 10.3 months for chemotherapy alone. Results also showed an increased confirmed objective response rate for Imfinzi plus chemotherapy (68% versus 58% for chemotherapy alone) and that Imfinzi added to chemotherapy delayed the time for disease symptoms to worsen.

An updated analysis recently showed sustained efficacy for Imfinzi plus chemotherapy after a median follow up of more than two years (OS HR: 0.75; 95% CI 0.62-0.91; nominal p=0.0032), with median OS of 12.9 months versus 10.5 months for chemotherapy alone. The safety and tolerability for Imfinzi plus chemotherapy were consistent with the known safety profile of these medicines. No patients tested positive for treatment-emergent anti-drug antibodies to Imfinzi.

The efficacy and safety results for Japanese patients in the CASPIAN trial were consistent with the overall trial population in a prespecified analysis. The CASPIAN trial used a fixed dose of Imfinzi (1,500mg), administered every three weeks for four cycles while in combination with chemotherapy and then every four weeks until disease progression.

Imfinzi, in combination with etoposide and either carboplatin or cisplatin, is also approved in the US and several other countries around the world for the treatment of ES-SCLC in the 1st-line setting and is currently under regulatory review in other countries. It was recently recommended for marketing authorisation in the EU for this indication.

As part of a broad development programme, Imfinzi is also being tested following concurrent chemoradiation therapy in patients with limited-stage SCLC in the Phase III ADRIATIC trial.