Alnylam Receives European Commission Approval for AMVUTTRA® (vutrisiran) for the Treatment of ATTR Amyloidosis with Cardiomyopathy

− First and Only RNAi Therapeutic Approved by the European Commission for the Treatment of Wild-Type or Hereditary ATTR Amyloidosis with Cardiomyopathy –

− Novel RNAi Mechanism Delivers Rapid Knockdown of Transthyretin (TTR), Addressing the Disease at its Source –

− Approval Based on HELIOS-B Phase 3 Study, Which Showed Up to 36% Reduction in All-Cause Mortality, With Preservation of Functional Capacity and Quality of Life, with Four Quarterly Doses Per Year –

− Decision Follows Recent Authorizations in the U.S. and Brazil −

Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY), the leading RNA interference (RNAi) therapeutics company, today announced that the European Commission (EC) has granted approval for the treatment of wild-type or hereditary transthyretin amyloidosis in adult patients with cardiomyopathy (ATTR-CM) as an additional indication for its orphan RNAi therapeutic AMVUTTRA^® (vutrisiran). The approval broadens the indication for AMVUTTRA, which now becomes the first and only RNAi therapeutic approved by the EC for the treatment of the cardiomyopathy manifestations of ATTR amyloidosis and the polyneuropathy manifestations of hereditary transthyretin-mediated amyloidosis (hATTR) in adults.

"Estimates show approximately 100,000 people are affected by ATTR amyloidosis across Europe, most with cardiomyopathy, so this approval marks a critical step toward addressing this underserved patient population," said Pushkal Garg, M.D., Chief Medical Officer at Alnylam. "AMVUTTRA is supported by a well-established efficacy and safety profile, with over 6,000 patient-years of global experience in the treatment of hATTR with polyneuropathy. By delivering rapid and sustained knockdown of TTR through convenient, quarterly dosing, it offers a clinically differentiated approach with the potential to transform outcomes for patients living with this debilitating and potentially fatal disease. We now look forward to securing access to AMVUTTRA for eligible patients across the EU as quickly as possible."

The EC decision is based on positive results from the pivotal HELIOS-B Phase 3 study – a randomized, double-blind, placebo-controlled, multicenter, global trial that enrolled a diverse group of patients reflective of the contemporary ATTR-CM population, including those receiving substantial concurrent use of available standard-of-care therapies such as tafamidis and SGLT2 inhibitors. AMVUTTRA met all 10 pre-specified primary and secondary endpoints across both the overall and monotherapy populations. These included statistically significant reductions in all-cause mortality and recurrent cardiovascular events, as well as significant improvements in functional capacity (6-minute walk test), health status and quality of life (Kansas City Cardiomyopathy Questionnaire), and heart failure symptoms and severity (NYHA class). In the overall population, AMVUTTRA achieved a 28% reduction in the primary composite of all-cause mortality and recurrent cardiovascular events as compared to placebo. Mortality in this population was significantly reduced by 36% through 42 months in a pre-specified secondary endpoint analysis which included up to 36 months of the double-blind period plus six months of open-label extension. In HELIOS-B, rates of adverse events (AEs), serious AEs, severe AEs and AEs leading to study drug discontinuation were similar between the AMVUTTRA and placebo arms. Adverse drug reactions of AMVUTTRA include injection site reactions and increase in blood alkaline phosphatase and alanine transaminase. Detailed results from the HELIOS-B study were published in The New England Journal of Medicine.¹

"The HELIOS-B findings provide compelling evidence to support the use of vutrisiran as a first-line treatment option for patients with ATTR-CM," said Marianna Fontana, M.D., Ph.D., HELIOS-B investigator, Professor of Cardiology, University College London, National Amyloidosis Center, Royal Free Hospital, London. "As a physician, it is a privilege to see the true impact on patients in the clinic. The trial enrolled a broad population reflective of real-world clinical practice, and that's what makes the results so meaningful. This is a milestone for patients, who now have a new treatment option that has the potential to significantly improve outcomes of this disease."

ATTR-CM is caused by the deposition of misfolded TTR fibrils, which drive progressive and irreversible cardiovascular damage and premature death. AMVUTTRA is an RNAi therapeutic that works upstream by delivering sustained knockdown of disease-causing TTR at its source. In the EU, it is administered as a subcutaneous injection once every three months, either by a healthcare professional, or self-administered by patients or their caregivers, offering flexibility in treatment delivery.

"Amyloidosis is a serious and progressive disease that significantly impacts not only patients' physical health, but also their quality of life and independence. I am thrilled by the news of a new therapy for people in the EU living with ATTR-CM who often face delayed diagnosis. Having a new treatment option available marks a welcome development for the amyloidosis community," said Giovanni d'Alessio, President of the Amyloidosis Alliance.

In May 2025, the European Medicines Agency's Committee for Orphan Medicinal Products (COMP) adopted a positive opinion on the maintenance of the EU Orphan Designation for AMVUTTRA in ATTR amyloidosis.

AMVUTTRA was approved in March 2025 by the U.S. Food and Drug Administration (FDA) and the Brazilian Health Regulatory Agency (ANVISA) for the treatment of the cardiomyopathy of wild-type or hereditary ATTR amyloidosis in adults. Alnylam continues to pursue additional global submissions to bring vutrisiran to patients worldwide.

AMVUTTRA^® (vutrisiran) INDICATION AND IMPORTANT SAFETY INFORMATION

Indications

In the EU, AMVUTTRA^® (vutrisiran) is indicated for the treatment of:

• hereditary transthyretin amyloidosis in adult patients with stage 1 or stage 2 polyneuropathy (hATTR-PN).
• wild-type or hereditary transthyretin amyloidosis in adult patients with cardiomyopathy (ATTR-CM).

Important Safety Information

Reduced Serum Vitamin A Levels and Recommended Supplementation

Vutrisiran treatment leads to a decrease in serum vitamin A levels. Supplementation of approximately, but not exceeding, 2500 IU to 3000 IU vitamin A per day is advised for patients taking vutrisiran. Patients should be referred to an ophthalmologist if they develop ocular symptoms suggestive of vitamin A deficiency (e.g., night blindness).

Adverse Reactions

Commonly reported adverse reactions with vutrisiran were injection site reactions and increase in blood alkaline phosphatase and alanine transaminase.

For additional information about vutrisiran, please see the full Summary of Product Characteristics.

About AMVUTTRA^® (vutrisiran)

AMVUTTRA^® (vutrisiran) is an RNAi therapeutic that delivers rapid knockdown of variant and wild‑type transthyretin (TTR), addressing the underlying cause of transthyretin (ATTR) amyloidosis. Administered quarterly via subcutaneous injection, vutrisiran is approved and marketed in more than 15 countries for the treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis (hATTR-PN) in adults. It is also approved in the U.S. and Brazil for the treatment of wild-type or hereditary ATTR amyloidosis in adult patients with cardiomyopathy (ATTR-CM). In the EU, AMVUTTRA is administered once every three months, either by a healthcare professional or through self-administration by patients or their caregivers.

About ATTR

Transthyretin amyloidosis (ATTR) is an underdiagnosed, rapidly progressive, debilitating and fatal disease caused by misfolded transthyretin (TTR) proteins, which accumulate as amyloid deposits in various parts of the body, including the nerves, heart and gastrointestinal tract. Patients may present with polyneuropathy, cardiomyopathy or both manifestations of disease. There are two different forms of ATTR – hereditary ATTR (hATTR), which is caused by a TTR gene variant and affects approximately 50,000 people worldwide, and wild-type ATTR (wtATTR), which occurs without a TTR gene variant and impacts an estimated 200,000-300,000 people worldwide.^2-5

About RNAi

RNAi (RNA interference) is a natural cellular process of gene silencing that represents one of the most promising and rapidly advancing frontiers in biology and drug development today.⁶ Its discovery has been heralded as "a major scientific breakthrough that happens once every decade or so," and was recognized with the award of the 2006 Nobel Prize for Physiology or Medicine.⁷ By harnessing the natural biological process of RNAi occurring in our cells, a new class of medicines known as RNAi therapeutics is now a reality. Small interfering RNA (siRNA), the molecules that mediate RNAi and comprise Alnylam's RNAi therapeutic platform, function upstream of today's medicines by potently silencing messenger RNA (mRNA) – the genetic precursors that encode for disease-causing or disease pathway proteins – thus preventing them from being made.⁶ This is a revolutionary approach with the potential to transform the care of patients with genetic and other diseases.

About Alnylam Pharmaceuticals

Alnylam (NASDAQ:ALNY) has led the translation of RNA interference (RNAi) into a whole new class of innovative medicines with the potential to transform the lives of people afflicted with rare and prevalent diseases with unmet need. Based on Nobel Prize-winning science, RNAi therapeutics represent a powerful, clinically validated approach yielding transformative medicines. Since its founding in 2002, Alnylam has led the RNAi Revolution and continues to deliver on a bold vision to turn scientific possibility into reality. Alnylam has a deep pipeline of investigational medicines, including multiple product candidates that are in late-stage development. Alnylam is executing on its "Alnylam P⁵x25" strategy to deliver transformative medicines in both rare and common diseases benefiting patients around the world through sustainable innovation and exceptional financial performance, resulting in a leading biotech profile. Alnylam is headquartered in Cambridge, MA.

Alnylam Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than historical statements of fact regarding Alnylam's expectations, beliefs, goals, plans or prospects including, without limitation, Alnylam's expectations regarding the safety and efficacy of AMVUTTRA for the treatment of ATTR-CM; the potential for AMVUTTRA to be used as a first-line treatment for ATTR-CM; the potential for AMVUTTRA to address the underserved ATTR-CM patient population and to improve outcomes for ATTR-CM patients; and Alnylam's ability to secure access to AMVUTTRA for eligible patients across the EU and the timing of such access should be considered forward-looking statements. Actual results and future plans may differ materially from those indicated by these forward-looking statements as a result of various important risks, uncertainties and other factors, including, without limitation, risks and uncertainties relating to: Alnylam's ability to successfully execute on its "Alnylam P⁵x25" strategy; Alnylam's ability to successfully demonstrate the efficacy and safety of its product candidates; the pre-clinical and clinical results for Alnylam's product candidates; actions or advice of regulatory agencies and Alnylam's ability to obtain regulatory approval for its product candidates, as well as favorable pricing and reimbursement; successfully launching, marketing and selling Alnylam's approved products globally; and any delays, interruptions or failures in the manufacture and supply of Alnylam's product candidates or its marketed products; as well as those risks more fully discussed in the "Risk Factors" filed with Alnylam's 2024 Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC), as may be updated from time to time in Alnylam's subsequent Quarterly Reports on Form 10-Q and in its other SEC filings. In addition, any forward-looking statements represent Alnylam's views only as of today and should not be relied upon as representing its views as of any subsequent date. Alnylam explicitly disclaims any obligation, except to the extent required by law, to update any forward-looking statements.

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Alnylam Pharmaceuticals, Inc.

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