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.
Olpasiran Vs. Pelacarsen: Same Target, Different Drug
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 can move in the meantime on a rival's results alone.
Repatha’s Growth Story Remains Intact
Here's the distinction that got lost in the recent sell-off: Repatha and Olpasiran aren't the same drug family at all.
Repatha is a PCSK9 inhibitor. It lowers LDL cholesterol, the "bad cholesterol" most people are already familiar with, and it's been on the market for years with a well-established track record. Olpasiran, by contrast, is an unproven, investigational Lp(a)-lowering drug that hasn't finished its outcomes trial.
Pelacarsen's failure says nothing directly about Repatha's mechanism or its results. Yet AMGN stock traded as if concerns around Amgen’s cardiovascular pipeline extended to Repatha as well. Repatha's fundamentals didn't budge: the drug grew revenue 37% year-over-year, with 35% volume growth, in Amgen's most recent quarter.
A late-stage failure in one experimental drug, from a different company, using a different mechanism, dragged sentiment on a commercial product doing exactly what it's supposed to do. For investors trying to separate the noise from the signal, Repatha is the clearest evidence that the sell-off was driven by a competitor's headline, not by Amgen's business.
AMGN Stock Remains Under Pressure
Despite the sell-off of nearly 10% on Sept. 8, AMGN has failed to reverse its slide in subsequent sessions. The stock is down more than 12% in the five trading days ending Sept. 10, most of which came during the initial sell-off. It’s now within about 6% of its 200-day simple moving average. If it drops below that, the May lows around $323 could be in play.
The Amgen analyst forecasts on MarketBeat support investors with a “buy the dip” mindset.
At around $380 per share in recent trading, AMGN is trading roughly in line with its consensus price target.
However, since the Novartis-fueled sell-off, Wells Fargo raised its price target to $435 from $400, Cantor Fitzgerald reiterated its $400 target, and BMO Capital Markets maintained a price target of $450 even after downgrading AMGN from Outperform to Market Perform.
That’s consistent with analyst sentiment since the company’s Q2 2026 earnings report.
It’s confirmation that institutional money is placing more weight on the company’s balance sheet than on algorithm-driven selling on a test result that didn’t involve Amgen.
The article "Amgen Drops 10% on a Trial It Didn't Even Run" first appeared on MarketBeat.
