Amgen's Cancer Therapy Hits Primary Endpoint, Shares Plummet 7.5%

Amgen announced positive results from its Phase 3 trial of IMDELLTRA, a DLL3-targeting therapy in combination with IMFINZI for extensive-stage small cell lung cancer. The study met its primary endpoint of improving overall survival. Shares fell 7.5% to $404.01 on August 21, 2026.

Amgen's Phase 3 trial, DeLLphi-305, evaluated the combination therapy as first-line maintenance for extensive-stage small cell lung cancer. The main study result was a landmark improvement in overall survival, according to PR Newswire.

The daily chart shows a split structure with shares holding above the MA-50 and MA-200 but sitting below the MA-20. Traders should watch for a close above $411.5 to indicate follow-through from buyers.

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