Alnylam Pharmaceuticals Inc Stock Price, News & Analysis

Alnylam (Nasdaq: ALNY) will invest $250 million to expand its 200,000 sq. ft. Norton, Massachusetts manufacturing site to add a proprietary, scalable siRNA enzymatic-ligation platform, siRELIS™. The expansion is intended to increase capacity, lower production costs, and produce clinical and commercial siRNA drug substance for programs including zilebesiran and nucresiran.

The siRELIS™ platform has been accepted into the FDA Emerging Technology Program to accelerate regulatory engagement. Construction is underway and new capabilities are expected to be fully operational by late 2027.

Alnylam (Nasdaq: ALNY) said it entered private repurchase agreements to buy approximately $34.4 million aggregate principal amount of its 1.00% Convertible Senior Notes due 2027 for a total cash repurchase cost of about $51.9 million including accrued interest.

The final cash price is subject to adjustment based in part on the daily volume-weighted average price of Alnylam common stock during a measurement period beginning December 11, 2025. The repurchases are expected to close shortly after that measurement period, subject to customary closing conditions.

After the transactions close, approximately $362.8 million aggregate principal amount of the Notes will remain outstanding, and previously entered capped call transactions are expected to remain in effect.

Alnylam (Nasdaq: ALNY) reported post hoc analyses from the HELIOS-B Phase 3 study of AMVUTTRA (vutrisiran) showing reductions in gastrointestinal (GI) adverse events and reinforcing monotherapy efficacy.

Key findings: a 42% lower GI event rate overall, 37% lower in vutrisiran monotherapy, and 49% lower in patients on tafamidis at baseline; individual symptoms (diarrhea, nausea, vomiting) fell >50% with rate ratios as low as 0.16. A censored monotherapy analysis showed a 32% reduction in the primary composite endpoint through 36 months (HR 0.68; 95% CI 0.49–0.95; p=0.022), consistent with the primary monotherapy HR 0.67 (p=0.016). AMVUTTRA has >8,000 patient‑years exposure and recent approvals in multiple regions.

Alnylam (Nasdaq: ALNY) announced Board changes effective December 2, 2025 and January 5, 2026.

Two directors departed: Mike Bonney stepped down after serving on the Board since 2014 and holding Board Chair roles from December 2015 to August 2021 and Executive Chair from August 2021 to January 2023; Carolyn Bertozzi, Ph.D., resigned from the Board after joining in 2023 and will continue as a scientific advisor following her election to the Eli Lilly board effective December 8, 2025.

New appointment: Stuart Arbuckle will join as an independent director on January 5, 2026; he spent 13 years at Vertex with senior commercial and operating responsibilities and currently serves on the Rhythm Pharmaceuticals board.

Alnylam (Nasdaq: ALNY) presented post hoc HELIOS-B analyses at AHA 2025 showing vutrisiran improved cardiac structure and function and preserved renal function in ATTR-CM patients.

Key imaging findings: CMR showed amyloid regression in 22% of treated patients vs 0% placebo at Year 3; mean ECV change was -0.10% with vutrisiran vs +7.86% with placebo (p=0.006). Renal results: fewer patients had ≥40% eGFR decline (12.7% vs 21.2%) and treatment reduced risk of death and CV events in patients progressing to CKD stage 4+ (HR 0.47; 95% CI 0.26–0.85).

Alnylam (Nasdaq: ALNY) said management will present company overviews at two investor conferences in November 2025:

• UBS Global Healthcare Conference — Monday, November 10, 2025 at 10:15 AM ET in Palm Beach Gardens, Florida
• Jefferies Global Healthcare Conference — Wednesday, November 19, 2025 at 11:30 AM GMT (6:30 AM ET) in London

Live audio webcasts of each presentation will be available on the Investors section of the company website and replays will be posted within 48 hours after each event.

Alnylam (NASDAQ: ALNY) reported Q3 2025 total net product revenues of $851M (103% YoY), driven by TTR revenues of $724M (135% YoY) led by AMVUTTRA. GAAP net income was $251M and non-GAAP net income was $396M for the quarter. The company raised 2025 guidance for the TTR franchise to $2,475M–$2,525M and total net product revenues to $2,950M–$3,050M.

Pipeline progress included HELIOS-B long‑term vutrisiran benefit data, start of ZENITH (zilebesiran) Phase 3 (~11,000 patients) and initiation of TRITON-PN; company reported a $300M Roche milestone and disclosed a U.S. Attorney subpoena related to government price reporting.

Alnylam (Nasdaq: ALNY) will report third-quarter 2025 financial results for the quarter ended September 30, 2025 on Thursday, October 30, 2025 before U.S. markets open.

Management will host a conference call and live audio webcast on October 30, 2025 at 8:30 AM ET to discuss results and outlook. The live webcast will be available on the company’s Investors events page at www.alnylam.com/events, and an archived webcast will be posted approximately two hours after the live event.

Alnylam Pharmaceuticals (Nasdaq: ALNY) has initiated the ZENITH Phase 3 cardiovascular outcomes trial for zilebesiran, dosing its first patient. The global study will evaluate zilebesiran as a biannual treatment for uncontrolled hypertension in approximately 11,000 patients across 35 countries.

The trial will assess zilebesiran's potential to reduce major adverse cardiovascular events in patients with uncontrolled hypertension who have established cardiovascular disease or are at high risk. This milestone has triggered a $300 million payment from partner Roche. Zilebesiran is an RNAi therapeutic targeting liver-expressed angiotensinogen (AGT) in the Renin-Angiotensin-Aldosterone System (RAAS), aiming to provide sustained blood pressure control with twice-yearly dosing.