A $12 billion sympathy drop

Amgen lost about $12 billion in market value after hours on September 4, 2026, sliding roughly 5% to $415. The trigger was a Novartis trial, not an Amgen one.

“The reason, as strange as it sounds, is a drug it does not own.”

The premise took the hit

Pelacarsen cut Lp(a) by about 80% but still failed to reduce cardiovascular death, heart attack, stroke, or urgent revascularization. That challenges the whole idea that lowering Lp(a) cuts events.

Olpasiran rides the same bet

Amgen's olpasiran is built on the identical hypothesis, so the market repriced its odds the moment pelacarsen's data landed. No new olpasiran data was needed.

The 15% deeper cut

Olpasiran dropped Lp(a) by more than 95% in Phase 2 versus roughly 80% for pelacarsen. Bulls say that extra depth delivers outcomes, but the failed trial gave no evidence such a threshold exists.

“It is therefore appropriate to say that the miss lowered olpasiran's probability of success rather than pretending it is irrelevant.”

Why 5% and not 25%

Amgen is no Lp(a) pure play. MariTide in obesity, Repatha in cholesterol, and Tezspire in asthma carry more value, and positioning stayed calm at 66 hedge funds and 2.4% short interest.

Setback, not a dip to buy

The deeper-cut argument is a hypothesis nobody has proved or disproved. Olpasiran's own outcomes readout settles it, but MariTide drives the stock in the meantime.

“Do not make the decision based on olpasiran alone.”