Amgen Inc. (NASDAQ:AMGN) experienced significant market volatility following a failed Phase 3 clinical trial conducted by competitor Novartis. On September 4, 2026, Amgen’s stock price fell by approximately 5% to $415, resulting in a market value decline of roughly $12 billion, as reported by Yahoo Finance.
The market reaction stems from the failure of Novartis’s Lp(a)-lowering therapy, pelacarsen, in the Lp(a)HORIZON trial. While the drug successfully reduced levels of lipoprotein(a)—a genetic cardiovascular risk factor—it failed to demonstrate a meaningful reduction in the composite of cardiovascular death, heart attack, stroke, and urgent revascularization. Because Amgen’s late-stage asset, olpasiran, operates on the same biological hypothesis, investors moved to reprice Amgen’s assets based on the negative read-through.
While Amgen’s olpasiran has demonstrated a higher percentage of Lp(a) reduction in earlier Phase 2 trials compared to pelacarsen, the Lp(a)HORIZON results failed to establish a clear clinical threshold where deeper reductions yield improved cardiovascular outcomes. Despite this, analysts note that Amgen remains diversified with other major drivers such as MariTide for obesity, Repatha for cholesterol, and Tezspire for asthma, which provided a partial cushion against further volatility.