At the European Society for Medical Oncology (ESMO) 2026 conference in Madrid, Spain, researchers unveiled promising results from a phase 3 trial of a combination therapy for extensive-stage small cell lung cancer. The study, published in the New England Journal of Medicine, showed that pairing Amgen's Imdeltra (tarlatamab) with AstraZeneca's Imfinzi (durvalumab) significantly improved survival outcomes compared to Imfinzi alone.
The trial, known as DeLLphi-305, enrolled 563 patients whose cancer had not progressed after initial chemotherapy. Patients who received the combination therapy had a median overall survival of 21.1 months, 8.4 months longer than those who received Imfinzi alone (12.7 months). The risk of death was reduced by 58%. Median progression-free survival was also longer with the combination (7.4 months) compared to Imfinzi alone (1.9 months), with a 66% lower risk of disease progression or death.
Imdeltra works by directing immune cells to attack cancer cells, binding to a protein on cancer cells (DLL3) and a receptor on T cells (CD3). While the combination therapy showed significant benefits, it also carried a higher risk of side effects. Treatment-related adverse events of grade 3 or higher occurred in 20.9% of patients in the combination arm, compared to 10.8% in the Imfinzi-only arm. About half of the patients in the combination arm experienced cytokine release syndrome (CRS), though most cases were mild.
The findings represent a meaningful advance in treating extensive-stage small cell lung cancer, a disease known for its difficulty to treat and high recurrence rates. However, whether these results will lead to expanded approval for Imdeltra and changes to treatment guidelines depends on decisions by national regulators and medical societies.