Alnylam Defends ATTR-CM Franchise After Rival's Wainua Trial Stumbles
- Full Phase 3 CARDIO-TTRansform results, presented at ESC Munich, showed AstraZeneca/Ionis's TTR silencer eplontersen (Wainua) failed to significantly cut cardiovascular death/events in ATTR-CM over roughly 140 weeks (rate ratio 0.89, p=0.277).
- Critically, patients already on a stabilizer (Pfizer's Vyndaqel, BridgeBio's Attruby) saw no added benefit from Wainua; only silencer-monotherapy patients showed a nominal gain.
- That subgroup split is uncomfortable for Alnylam, whose Amvuttra and pipeline candidate nucresiran are the same drug class and increasingly used alongside stabilizers.
- Alnylam shares fell nearly 5%.
- Executives countered that Amvuttra achieves deeper TTR knockdown than eplontersen and that nucresiran's larger TRITON-CM trial should avoid Wainua's pitfalls.
The subgroup data is the real story: if silencers add nothing once patients are already stabilized, the industry's drift toward stabilizer-plus-silencer combos loses its evidence base, and AZ/Ionis must reposition Wainua as monotherapy — a much smaller, harder-to-sell market. That's a strategic problem, not just a trial miss, and it makes Intellia's one-and-done knockdown pitch relatively more attractive. Alnylam's rebuttal (deeper knockdown, a bigger trial) is the self-interested defense you'd expect from a company facing guilt-by-association, resting on cross-trial comparisons Alnylam itself is asserting, not independent data — treat "deeper knockdown" as a hypothesis until TRITON-CM reads out. Nucresiran's margin for error just got narrower. Watch prescriber messaging: whoever wins the "silencer as add-on vs. backbone" argument sets ATTR-CM's standard of care.
Alnylam defends heart disease drugs after failure of AstraZeneca's Wainua ↗