AstraZeneca has announced that the US Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to Imfinzi (durvalumab) for the treatment of small cell lung cancer (SCLC).

The decision comes hot on the heels of the Phase III CASPIAN trial, which met its primary endpoint by showing a statistically-significant and clinically-meaningful improvement in overall survival for patients with extensive-stage SCLC. These patients were treated with Imfinzi in combination with standard-of-care etoposide and platinum-based chemotherapy, compared to chemotherapy alone.

The drug, ahuman monoclonal antibody that binds to PD-L1 and blocks the interaction of PD-L1 with PD-1 and CD80, countering the tumour's immune-evading tactics and releasing the inhibition of immune responses. It is also being tested following concurrent chemoradiation therapy in limited-stage SCLC in the Phase III ADRIATIC trial.

José Baselga, Executive Vice President, R&D Oncology said that the CASPIAN trial is the first trial to offer the “flexibility of combining immunotherapy with different platinum-based regimens in small cell lung cancer,” and that the company is “eager to expand treatment options for patients facing such a devastating diagnosis and look forward to working with regulatory authorities to bring forward new options as soon as possible.”

It is also currently approved for unresectable, stage III non-small cell lung cancer (NSCLC) after chemotherapy and radiation therapy in more than 45 countries including the US, EU, and Japan based on the Phase III PACIFIC trial.

Lung cancer is the leading cause of cancer death among both men and women and accounts for about one-fifth of all cancer deaths. Lung cancer is broadly split into NSCLC and SCLC, with about 15% classified as SCLC. About two-thirds of SCLC patients are diagnosed with extensive-stage disease, in which the cancer has spread widely through the lung or to other parts of the body.