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IONS
Oof, that’s a Phase 3 miss
Ionis Pharmaceuticals and AstraZeneca just watched their big ATTR-CM trial trip over the finish line — and then roll straight into the mud. Their Phase 3 CARDIO-TTRansform study of eplontersen failed to meet its primary efficacy endpoint, which is a very polite way of saying the drug did not prove it could beat placebo at reducing the combined risk of cardiovascular death and recurring cardiovascular events.
That’s a rough headline for a company trying to turn a late-stage asset into a meaningful commercial win. Ionis stock was down almost 9% after the news, because biotech investors tend to treat Phase 3 results like a courtroom verdict: you either walk out with a trophy or a very expensive lesson.
Why the market cares
This one matters beyond Ionis because ATTR-CM is one of those juicy, competitive markets where every new data read can shuffle the deck.
A few immediate takeaways:
- The study was run on top of contemporary standard of care, and a majority of patients were already on a transthyretin stabilizer.
- Adding eplontersen didn’t meaningfully improve outcomes versus placebo through Week 140.
- That weakens the case for combining a silencer with a stabilizer in this disease.
Translation: the market is now leaning harder toward monotherapy and toward the therapies already in the clubhouse. Analysts pointed out that this is a win for existing players like Alnylam’s Amvuttra, BridgeBio’s Attruby, and Pfizer’s tafamidis.
Rivals get to do a little happy dance
Nobody’s sending thank-you flowers, but the competitive math is pretty clear. If eplontersen can’t show a benefit in this setup, that removes a would-be challenger from an ATTR-CM market that already has some momentum behind newer options.
That’s why investors in ALNY, BBIO, and even PFE may view this as a “not my stock, but still my problem” kind of day — except in reverse. The failure supports the idea that newer therapies may not need to be paired up to do the job, which is exactly the kind of narrative you want when you’re selling a differentiated treatment.
Big picture: Ionis didn’t just miss a trial endpoint — it handed rivals a cleaner runway. In biotech, that’s the difference between “future growth driver” and “well, back to the drawing board.”