FDA grants traditional approval to tarlatamab-dlle for extensive stage small cell lung cancer

Regulatory approval: On Nov 19, 2025, the FDA granted traditional approval to tarlatamab-dlle (Imdelltra; Amgen) for adults with extensive-stage small cell lung cancer (ES-SCLC) whose disease progressed on or after platinum-based chemotherapy. The drug previously received accelerated approval for this indication in 2024. Approval was supported by the randomized DeLLphi-304 trial, which showed improved overall survival versus investigator’s choice chemotherapy, with boxed warnings for cytokine release syndrome and neurologic toxicity (including ICANS).

FDA traditional approval: tarlatamab-dlle in ES-SCLC (Nov 19, 2025)

Type: Regulatory approval (FDA)

On November 19, 2025, the FDA granted traditional approval to tarlatamab-dlle (Imdelltra; Amgen Inc.) for adults with extensive-stage small cell lung cancer (ES-SCLC) with disease progression on or after platinum-based chemotherapy. Tarlatamab-dlle had received accelerated approval for this indication in 2024.

Supporting efficacy evidence (DeLLphi-304; NCT05740566)

DeLLphi-304 was a multicenter, randomized, open-label trial enrolling patients with SCLC progressing after platinum-based chemotherapy with or without an anti–PD-(L)1 antibody. 509 patients were randomized 1:1 to tarlatamab-dlle or investigator’s choice SOC chemotherapy (topotecan, lurbinectedin, or amrubicin) until progression or unacceptable toxicity.

  • Primary endpoint (OS): median 13.6 months (95% CI: 11.1, not evaluable) with tarlatamab-dlle vs 8.3 months (95% CI: 7.0–10.2) with SOC; HR 0.60 (95% CI: 0.47–0.77); p<0.001.
  • PFS: median 4.2 vs 3.2 months; HR 0.72 (95% CI: 0.59–0.88); p<0.001.
  • Statistically significant improvement in dyspnea at week 18 vs SOC.

Safety and dosing

Prescribing information includes a Boxed Warning for life-threatening or fatal cytokine release syndrome and neurologic toxicity, including ICANS, plus warnings/precautions for cytopenias, infections, hepatotoxicity, hypersensitivity, and embryo-fetal toxicity. Recommended dose: 1 mg (Cycle 1 Day 1), then 10 mg (Days 8, 15, and every 2 weeks thereafter).

Review used Project Orbis and RTOR; partner-agency reviews were ongoing.

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