On November 19, 2025, the FDA granted traditional approval to tarlatamab-dlle (Imdelltra) for adults with extensive-stage small cell lung cancer that progressed after platinum-based chemotherapy. This approval follows its accelerated approval in 2024.1
Efficacy was evaluated in the DeLLphi-304 trial (NCT05740566), a multicenter, randomized, open-label study involving 509 patients. Participants received either tarlatamab-dlle or standard-of-care (SOC) chemotherapy (topotecan, lurbinectedin, or amrubicin) until disease progression or unacceptable toxicity. The primary end point, overall survival (OS), was significantly improved with tarlatamab-dlle (median OS: 13.6 months) compared with SOC (8.3 months) with a hazard ratio of 0.60 (P<.001). Progression-free survival (PFS) was also improved with tarlatamab-dlle (median PFS: 4.2 months vs 3.2 months; 0.72; P<.001). In addition, patients on tarlatamab-dlle experienced statistically significant improvement in dyspnea at week 18.
Tarlatamab-dlle carries a Boxed Warning for life-threatening or fatal cytokine release syndrome and neurologic toxicity, including immune effector cell–associated neurotoxicity syndrome. Other warnings include cytopenias, infections, hepatotoxicity, hypersensitivity, and embryo-fetal toxicity.
The recommended dose is 1 mg on cycle 1, day 1, followed by 10 mg on days 8 and 15, then every 2 weeks until disease progression or unacceptable toxicity.
Reference
- US Food and Drug Administration. FDA grants traditional approval to tarlatamab-dlle for extensive-stage small cell lung cancer. November 19, 2025. Accessed November 30, 2025. www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-traditional-approval-tarlatamab-dlle-extensive-stage-small-cell-lung-cancer