The question in every pharma investment committee today is not whether Novartis made a mistake. It is whether the science behind an entire drug class was wrong from the start.
Amgen suffered its steepest one-day sell-off since October 2000 on Tuesday, September 8, 2026, falling 10.08% to become the worst-performing Dow Jones stock in the session after Novartis’s pelacarsen, despite lowering Lp(a) levels in participants receiving standard care, failed to meet its primary endpoint, a composite of cardiovascular death, non-fatal heart attack, non-fatal stroke, and urgent coronary revascularization requiring hospitalization. The Dow itself fell 628.18 points, or 1.18%, to close at 52,786.07, its second straight losing session. Amgen, as one of the larger weights in the price-weighted index, was responsible for a substantial share of that move.
The irony is sharp. Amgen and AstraZeneca reported positive Phase 3 topline results for TEZSPIRE in eosinophilic esophagitis in late August, and Amgen separately announced landmark overall survival results for IMDELLTRA in combination with AstraZeneca’s Imfinzi in extensive-stage small cell lung cancer on September 8. None of it mattered. The market had a single question, and the question was about Lp(a).
The Bull Case: Pelacarsen Is Not Olpasiran
The argument for Amgen rests on mechanism and magnitude. Olpasiran and lepodisiran silence the gene encoding apolipoprotein(a) via RNA interference, while pelacarsen is an antisense oligonucleotide. That is a meaningful distinction. In Phase 2 trials, olpasiran reduced Lp(a) levels by more than 95% at some doses compared to placebo, and follow-up has shown suppression can persist well beyond the last dose. Pelacarsen achieved roughly 72% reduction in earlier studies. Depth of suppression may be the variable that determines whether clinical benefit emerges at all.
Truist Securities told investors that for olpasiran, the situation now shifts to higher-risk/higher-reward rather than becoming outright impaired, pointing to the deeper Lp(a) reduction and OCEAN(a)’s enrollment of a more high-risk population as meaningful differentiators from the Novartis program.
The Bear Case: The Hypothesis Itself Is on Trial
Citi is not reassured by the mechanistic arguments. The bank said the Lp(a) hypothesis is “weakened, but not disproven,” noting that details remain scarce beyond the topline miss, and that more data is needed to determine whether the failure reflects pelacarsen’s mechanism, trial design, or a broader challenge to the idea that lowering Lp(a) reduces heart attacks and strokes. The crucial word is “broader.” If the hypothesis fails, it fails for everyone.
Citi framed it in terms of the entire class: the first dedicated outcomes failure lowers confidence across the class and places greater pressure on later studies to demonstrate that deeper lowering can produce a clinically meaningful approximately 15% reduction in major adverse cardiovascular events. That is the bar every remaining program now has to clear.
Amgen’s pipeline, especially olpasiran, must deliver to offset looming declines as several in-line products face loss of exclusivity in the second half of the decade. A hypothesis under question is a poor foundation for that task.
What Investors Are Missing
The market sold Eli Lilly about 2% on the same read-through. That is almost certainly mispriced in one direction or the other. Lilly’s lepodisiran is being studied in a broader patient population, including some who have not yet developed established cardiovascular disease, limiting the direct read-through from Novartis’s failure. Lepodisiran is also less material to Lilly’s overall valuation, Citi noted. A 2% move for a company where cardiovascular is a distant secondary concern is almost certainly proportionate. A 10% move for Amgen, where olpasiran carries pipeline weight in the context of significant patent pressure, is at minimum a reasonable read.
The overlooked issue is timing. Lepodisiran’s ACCLAIM-Lp(a) Phase 3 readout is not expected until 2029, and olpasiran’s OCEAN(a) outcomes study is currently tracked for primary completion in 2028. Both companies are being revalued today on a hypothesis that will not be tested by their own data for years. That gap is where the opportunity or the additional risk lives, depending on which analyst you sit closer to.
Stocks to Watch
AMGN: The steepest loser, and the one most exposed. BMO Capital downgraded Amgen to Market Perform with a price target of $450 on the same day as the sell-off. With the OCEAN(a) readout still years out, the stock is now an opinion on whether deeper Lp(a) suppression cracks what pelacarsen could not.
LLY: Lilly’s lepodisiran shows up to about 94% Lp(a) reduction in Phase 2. The read-through risk is real but more limited than the market’s reaction implies. The oral muvalaplin program adds a second, structurally distinct Lp(a) asset.
IONS: For Ionis, the pelacarsen result compounds a difficult stretch, following its eplontersen program’s Phase 3 failure in transthyretin-mediated amyloid cardiomyopathy announced in July 2026, making two major antisense cardiovascular setbacks within three months.
NVS: Analysts had modeled peak annual sales of around $4 billion to $5 billion for pelacarsen if it had succeeded. That revenue is gone, and it lands on top of an already steep patent cliff.
