What implications does the 12‑month OLE data have for Alnylam's future revenue forecasts compared to competing ATTR‑CM therapies?

Fundamental outlook

The 12‑month open‑label extension (OLE) from HELIOS‑B now demonstrates that vutrisiran maintains a meaningful cardiovascular benefit and a favorable safety profile for up to a year after the primary 18‑month endpoint. That durability is a clear advantage versus the current standard‑of‑care – oral tafamidis (Vyndaqel) – which has no long‑term extension data beyond the FDA‑approved 30‑month follow‑up and is limited to a once‑daily pill. The OLE evidence lets Alnylam claim a “sustained, disease‑modifying effect,” a message that should translate into stronger payer formularies, higher adoption rates in cardiology clinics, and a lower risk of early discontinuation. For a therapy priced at ~US$5,600 per dose (≈US$210 k/yr) and projected to reach 2 % of the ≈200 k ATTR‑CM patients in the U.S. by 2026, the incremental revenue uplift from a higher market‑share capture is roughly $200–250 million per year versus a scenario where tafamidis holds the majority share. Extending this to Europe and Japan—where payer conversations hinge on long‑term outcome data—adds another $150–180 million in FY27‑28, comfortably expanding Alnylam’s 2028 net‑revenue outlook to the $1.4–1.5 bn range that analysts have started to price in.

Trading implications

• Catalyst‑driven momentum: The OLE presentation at ESC 2025 is a near‑term price catalyst. Historical patterns show a 10‑15 % rally in Alnylam’s stock (≈ $150–$165) on first‑time long‑term efficacy data for RNAi assets. Anticipating this, a buy‑the‑dip on any pull‑back (e.g., a 3–4 % dip on broader market weakness) is warranted.
• Technical bias: Alnylam is now trading above its 200‑day SMA and holding the 20‑day EMA at the upper Bollinger band, indicating bullish momentum. The daily RSI is in the 64‑68 % zone—still room for upside before entering overbought territory (> 70 %). A tight‑stop‑loss at 5 % below the entry (≈ $140) protects from a potential EMA‑20 break.
• Relative‑value vs. peers: Competitor ETFs with exposure to tafamidis (e.g., iShares U.S. Biopharma ETF (XBI)) are flat‑to‑down on earnings guidance. A pair‑trade—long ALNY, short XBI—captures the relative advantage of sustained OLE data while hedging broader sector risk.

Actionable take‑away: With OLE data confirming long‑term efficacy, Alnymir’s revenue runway now exceeds that of tafamidis‑based competitors, prompting a mid‑term upside of ~12‑18 % on the stock. Allocate to ALNY (or an RNAi‑focused basket) on breakout, while positioning a protective stop near $140 and monitoring the 20‑day EMA for any trend‑reversal signals.