Tarlatamab Combo Shows Unprecedented Survival in Small Cell Lung Cancer

Small cell lung cancer is one of the hardest cancers to treat, and patients with the most advanced form — called extensive-stage — have historically survived only about 10 to 15 months after starting treatment. A new clinical trial is changing that expectation in a major way.

Results from a study called DeLLphi-303, presented at the World Conference on Lung Cancer in Barcelona and published in Lancet Oncology, showed that a drug combination used as “maintenance therapy” — treatment given after the first round of chemotherapy to keep the cancer from coming back — produced a median overall survival of 25.3 months. That means half of patients in the study were still alive more than two years after starting treatment. At the 12-month mark, 82% of patients were alive, and 75% were still living at 18 months.

The treatment combined tarlatamab (brand name Imdelltra) with a PD-L1 inhibitor, a type of immunotherapy. Tarlatamab works differently from traditional drugs — it acts like a bridge, grabbing onto both cancer cells and immune cells at the same time to help the immune system attack the tumor more directly.

Dr. Kelly Paulson, who led the study, called the survival results “unprecedented.” Dr. Charles Rudin of Memorial Sloan Kettering, who reviewed the findings, said simply, “Wow,” adding that two-year survival in this disease is something doctors have never seen before.

Of the 88 patients enrolled across 30 centers in 13 countries, the most common serious side effects included cytokine release syndrome — an immune overreaction — in about one in four patients. No patients died from treatment-related causes.

Researchers are now moving forward with a larger phase III trial called DeLLphi-305, which will compare this combination directly against the current standard of care, with the potential to reshape how advanced small cell lung cancer is treated.