Tarlatamab plus durvalumab improved survival versus durvalumab alone in extensive-stage small cell lung cancer, Amgen reports in interim phase 3 results

1. In DeLLphi-305, tarlatamab plus durvalumab improved overall survival versus durvalumab alone, with a hazard ratio of 0.42 (95% CI, 0.32 to 0.54; P < 0.001).

2. Grade 3 or higher treatment-related adverse events occurred in 20.9% and 10.8% of patients, respectively; cytokine release syndrome occurred in 49.6% with tarlatamab.

Evidence Rating Level: 2 (Good)

2MM Brief: Amgen reported interim phase 3 results showing improved survival with tarlatamab plus durvalumab for patients with extensive-stage small cell lung cancer (ES-SCLC) receiving first-line maintenance treatment. In the global, randomized, open-label DeLLphi-305 trial, 563 patients who had not progressed after durvalumab, platinum-based chemotherapy and etoposide were randomized 1:1 to tarlatamab plus durvalumab or durvalumab alone until progression or unacceptable toxicity. The primary outcome was overall survival (OS), with progression-free survival (PFS) and objective response rate as secondary endpoints. At a median follow-up of approximately 16 months, the combination reduced the risk of death versus durvalumab alone, with an OS hazard ratio of 0.42 (95% confidence interval [CI], 0.32 to 0.54; P < 0.001); median OS was 21.1 months versus 12.7 months. At one year, 95% CI estimates for survival were 74.2, 83.7 with the combination and 47.3, 59.0 with durvalumab alone. At a median follow-up of 13.9 months, the combination reduced the risk of progression or death, with a PFS hazard ratio of 0.34 (95% CI, 0.28 to 0.42; P < 0.001); median PFS was 7.4 months versus 1.9 months. Objective response rates were 26.4% (95% CI, 20.9, 32.5) and 4.1% (95% CI, 2.0, 7.4), respectively (P < 0.001). Grade 3 or higher treatment-related adverse events occurred in 20.9% and 10.8% of patients. Cytokine release syndrome occurred in 49.6% of patients receiving tarlatamab, predominantly at Grade 1 or Grade 2; one Grade 3 event and no Grade 4 or greater events were reported. The study included treated and untreated asymptomatic brain metastases, and benefits were reported across prespecified subgroups. These interim results were reported by Amgen at the ESMO Congress 2026 and simultaneously published in The New England Journal of Medicine. The open-label design and interim analysis limit interpretation, although the findings support further evaluation of tarlatamab plus durvalumab as first-line maintenance treatment in ES-SCLC.

Click here to read the press release from Amgen

Source: a press release from Amgen; the results were also published in The New England Journal of Medicine.

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