Amgen Drops 10% on a Trial It Didn't Even Run

Amgen Inc. NASDAQ: AMGN delivered a strong earnings report on Aug. 4. AMGN stock rose approximately 17% from the Aug. 4 close through early September before reversing sharply. One of the highlights of Amgen’s report was Repatha, Amgen's approved PCSK9 drug, which posted $953 million in Q2 2026 revenue, a 37% year-over-year increase. But those gains have mostly been erased due to what can only be labeled as guilt by association. The event in question was a disappointing readout of a Phase 3 clinical trial from Novartis NYSE: NVS . The Swiss-based company reported that its cholesterol drug, Pelacarsen, failed to reduce cardiovascular events in a Phase 3 trial. It’s not unusual for an entire sector to get sold off after one company’s disappointing results. Case in point, even Eli Lilly & Co. NYSE: LLY stock dropped around 2%. However, there’s an important wrinkle that the high-speed trading programs don’t care much about. Amgen Delivered Successful Trial Results On the same day that Novartis reported its disappointing results, Amgen delivered a positive Phase 3 readout of its own that same morning. The company’s DeLLphi-305 trial evaluated its DLL3-targeted bispecific tarlatamab (Imdelltra), in combination with AstraZeneca’s Imfinzi (durvalumab), as first-line maintenance therapy for extensive-stage small cell lung cancer. Amgen announced the positive readout, including a statistically significant overall survival benefit. That didn’t stop investors from selling AMGN stock hard. However, that may be due to another wrinkle, which is the difference between Amgen’s cholesterol drug, Olpasiran and Pelacarsen. Both drugs attack the same target: lipoprotein(a), or Lp(a), a genetically inherited cholesterol particle linked to heart attacks and strokes. Unlike LDL cholesterol, diet and exercise don't move Lp(a) much. That's why drugmakers have spent years chasing it. But "same target" doesn't mean "same drug." Pelacarsen lowered Lp(a) by roughly 72% to 80% in earlier studies. Olpasiran, Amgen's candidate, cut Lp(a) levels by more than 95% in Phase 2 testing. Some analysts think that gap in potency could be part of the story: Pelacarsen may simply not have suppressed Lp(a) deeply enough to show a benefit, rather than proving the Lp(a) theory wrong altogether. Amgen also built its trial differently. Olpasiran is dosed quarterly, versus Pelacarsen's more frequent schedule. And Amgen narrowed its primary success measure to exclude ischemic stroke, arguing that particular outcome has a weaker genetic tie to Lp(a). Whether regulators and doctors accept that reasoning is still an open question, but it's a meaningfully different bet than the one Novartis just lost. None of this guarantees Olpasiran succeeds. Amgen’s own outcomes data, from the Phase 3 OCEAN(a)-Outcomes trial, isn't expected until 2028. The trial’s estimated primary completion date is March 31, 2028. Investors are being asked to wait years for proof, with the recent sell-off showing how much sentiment...