Amgen (AMGN) 2026 European Society for Medical Oncology (ESMO) Annual Congress summary

DeLLphi-305 efficacy

• Randomized patients without progression after four induction chemo-immunotherapy cycles to IMDELLTRA plus IMFINZI or IMFINZI; OS was the primary endpoint.

• At the July 7, 2026 cutoff, median OS was 21.1 vs 12.7 months; HR 0.42 (95% CI 0.32–0.54), P<0.001, with 87 vs 156 deaths.

• Median PFS was 7.4 vs 1.9 months; HR 0.34 (95% CI 0.28–0.42), P<0.001.

• ORR was 26.4% vs 4.1%; median DOR was 12.7 vs 5.6 months.

• OS benefit was consistent across prespecified subgroups, including patients with brain or liver metastases; presenters said results support a new first-line maintenance standard of care in ES-SCLC.

Safety and earlier clinical evidence

• Treatment-related adverse events led to discontinuation in 5.8% for IMDELLTRA and 3.2% for IMFINZI; no treatment-related fatalities were reported.

• CRS occurred in 49.6% of combination-arm patients; most events resolved with supportive care, with no fatal CRS or ICANS events.

• One Grade 3 CRS case and no Grade 3+ ICANS cases were reported; treatment-related events leading to drug holds or discontinuations were 3% for each drug.

• In Phase 1b DeLLphi-303, first-line maintenance IMDELLTRA plus a PD-L1 inhibitor showed median OS of 37.9 months at 30.8 months' median follow-up; survival follow-up remained ongoing.

IMDELLTRA development plans

• DeLLphi-312 is evaluating IMDELLTRA with chemo-immunotherapy for first-line induction and maintenance; DeLLphi-306 is testing it after concurrent chemoradiotherapy in limited-stage disease.

• DeLLphi-309 is evaluating extended IV dosing and DeLLphi-315 subcutaneous dosing; DeLLphi-310 and DeLLphi-313 are testing combinations with B7-H3 and DLL3 ADCs.

• Development also includes IMDELLTRA alone and in combinations for neuroendocrine cancers and other DLL3-expressing tumors; a Phase II lung neuroendocrine carcinoma trial was recruiting in Europe, with GI and other tumor studies planned.

• Rapid regulatory filings for DeLLphi-305 were planned; median treatment duration was 46 weeks in DeLLphi-305 vs 18 weeks in second-line DeLLphi-304, with DeLLphi-305 follow-up ongoing.

• DeLLphi-305 maintenance response rate was 26% vs 4%; over half of combination-arm responders remained in response at one year, and 44% remained on treatment at cutoff vs 11% on IMFINZI alone.