Plain language summary: tarlatamab for patients with previously treated small cell lung cancer

What is this summary about?: This is a summary of a phase 2 clinical study called DeLLphi-301. The study looked at how effective and safe a medicine called tarlatamab was in participants with small cell lung cancer (SCLC). Participants previously received at least two other treatments for their SCLC. Tarlatamab is a new medicine that locates a protein called DLL3 on the cancer, which allows T cells to attack the cancer. T cells belong to the body's natural defense system known as the immune system. The DeLLphi-301 study separated participants into two groups to receive tarlatamab 10 mg or 100 mg to determine which dose best shrank SCLC with minimal side effects. All participants received a small first dose (1 mg tarlatamab) to decrease the risk of an immune system reaction called cytokine release syndrome (CRS). Tarlatamab was given through the participant's vein once every 2 weeks. This method of administration is known as intravenous (IV) infusion. What were the results of the DeLLphi-301 study?: In the group given 10 mg tarlatamab, 40% of participants responded to treatment (cancer shrank). In the group given 100 mg tarlatamab, 32% of participants responded to treatment (cancer shrank). After taking tarlatamab at either dose, 59% of participants lived for at least 6 months without their cancer growing or getting worse. The most common side effect was CRS, which occurred in 51% of participants in the group given 10 mg tarlatamab and 61% of participants in the group given 100 mg tarlatamab. Other common side effects were decreased appetite, fever, constipation, and anemia. Some participants had a type of immune reaction called immune effector cell–associated neurotoxicity syndrome (ICANS). A small number of participants (3%) stopped taking tarlatamab because of side effects related to tarlatamab. What do the results from the DeLLphi-301 study mean?: The study found that tarlatamab given every 2 weeks shrank SCLC in participants with SCLC who received previous treatments. Participants given the 10 mg tarlatamab dose had fewer side effects than those given the 100 mg tarlatamab dose. Clinical Trial Registration:NCT05740566 (DeLLphi-304) (ClinicalTrials.gov).