− Efforts Aimed at Facilitating Earlier Diagnosis, Coordinated Care, and Long-Term Patient Impact in ATTR-CM –

− Alnylam to Host TTR Investor Webinar Today at 9:30 am ET –

Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY), the leading RNAi therapeutics company, today announced a set of strategic efforts designed to accelerate earlier recognition and improve care coordination for patients with the cardiomyopathy of wild-type or hereditary transthyretin-mediated amyloidosis (ATTR-CM). Through complementary initiatives with Viz.ai and the American Heart Association, Alnylam is advancing a comprehensive, system‑level approach to address persistent challenges of underdiagnosis and fragmented care in ATTR‑CM.

ATTR‑CM is a rapidly progressive, life‑threatening cause of heart failure that remains significantly underrecognized. Early and accurate diagnosis is critical to enabling access to appropriate management and improving outcomes. Despite advances in treatment, many patients remain undiagnosed for years, preventing access to necessary care. Alnylam aims to move ATTR-CM diagnosis upstream, accelerating earlier identification and enabling health systems to deliver consistent, high‑quality patient care at scale.

"As a cardiologist, I've seen firsthand the devastating impact of diagnosing ATTR‑CM too late," said Sameer Bansilal, M.D., M.S., Vice President, Global TTR Medical Lead, Alnylam Pharmaceuticals. "This is a progressive disease where timing truly matters – earlier recognition can fundamentally change a patient's course of disease. Alnylam's leadership in ATTR amyloidosis is grounded not only in deep science, a robust R&D program, and strong clinical evidence, but in a commitment to enduring impact – improving how this disease is identified and managed in real-world care. By working with leading health systems, technology innovators, and national clinical organizations, Alnylam is dedicated to building the infrastructure needed to diagnose ATTR-CM earlier and deliver more coordinated care."

Strengthening Detection and Care Coordination for ATTR-CM in Collaboration with Viz.ai

Alnylam is partnering with Viz.ai, the leader in artificial intelligence (AI)-powered disease detection and care coordination, to develop an AI-enabled ATTR-CM care pathway designed to help clinicians identify patients earlier in the course of disease and guide appropriate diagnostic evaluation and referral. The pathway combines a U.S. Food and Drug Administration (FDA)-cleared echocardiography AI algorithm, Us2.ai, with electronic health record connectivity and integration into routine clinical practice to support earlier recognition of ATTR-CM and facilitate coordinated care across cardiology and heart failure teams.

The collaboration includes the AI-Enhanced Echocardiography Workflow to Advance Recognition and Diagnosis of Cardiac Amyloidosis (AWARE) study – one of the first multi-system prospective implementation studies designed to evaluate how AI-enabled screening can be integrated into routine clinical workflows and assess its impact on diagnostic timelines, care coordination, and clinical decision-making in ATTR-CM. While AI technologies hold significant promise for improving disease detection, implementation and adoption within real-world clinical settings remain a key challenge, and the AWARE study is intended to help address this barrier by evaluating practical approaches to integrating AI tools into existing care pathways.

The initiative will launch at five pilot health systems later this year, representing a diverse set of clinical settings, with the goal of generating real-world evidence to inform broader, scalable adoption across health systems in the Viz.ai network.

"When ATTR‑CM is identified late, patients face the risk of disease progression and poorer outcomes," said Tim Showalter, M.D., Chief Medical Officer, Viz.ai. "By embedding AI‑driven detection into everyday clinical workflows and pairing it with coordinated care pathways, this collaboration focuses on closing the gap between the first clinical signal and meaningful clinical action, so more patients are identified and connected to care sooner before irreversible damage has occurred."

Improving Systems of Care for ATTR-CM by Supporting the American Heart Association

Complementing AI-enabled diagnostic technology, Alnylam is supporting a national effort focused on strengthening systems of care for people living with ATTR‑CM, led by the American Heart Association, an organization devoted to changing the future to a world of healthier lives for all.

The three-year initiative will convene a 10-site cohort of multidisciplinary health systems in a national learning collaborative designed to identify gaps in care, share best practices, and scale effective models for diagnosing and managing ATTR-CM. Participating centers will evaluate current practice pathways across diagnosis, referral, treatment, and follow-up in order to improve coordinated care and optimize patient outcomes. Insights generated through the program will be disseminated nationally to help improve care delivery and outcomes for patients with ATTR‑CM. This work will amplify proven, replicable models of excellence with the goal of enabling a stronger, more integrated system of care for patients nationwide.

Alnylam is a proud supporter of the American Heart Association's ATTR-CM Discovery Initiative: Improving the System of Care Across the ATTR Patient Journey.

Shaping the Future of ATTR-CM Care

Together, these efforts reflect Alnylam's leadership in redefining how ATTR‑CM is identified and managed, by shifting diagnosis earlier, strengthening care pathways, and enabling more consistent, coordinated care at scale. By investing in AI‑enabled detection, real‑world evidence, and system‑level partnerships, Alnylam aims to address the root causes of underdiagnosis and fragmentation and help ensure that patients are identified at a point when intervention may make the greatest difference.

Alnylam leadership will discuss these initiatives and how the Company is shaping the future of ATTR-CM care in a webinar today at 9:30 am ET. The webinar can be accessed on the Investors section of the Company's website at www.alnylam.com/events. An archived webcast will be available on the Alnylam website approximately two hours after the event.

About Transthyretin Amyloidosis (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 wild-type ATTR (wtATTR), which occurs without a TTR gene variant. It is estimated that 350,000 people worldwide live with ATTR, although ~80% remain undiagnosed.

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. 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. 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.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) is a leading global biopharmaceutical company and the pioneer of the RNA interference (RNAi) revolution. The Company is focused on developing transformative therapies with the potential to prevent, halt, or reverse disease. For more than two decades, Alnylam has advanced the Nobel-Prize-winning science of RNAi, delivering critical breakthroughs and six approved medicines. Alnylam has medicines available in more than 70 countries and a rapidly expanding and robust pipeline, in addition to consistently being recognized as an exceptional workplace and socially responsible organization. The Company is executing on its Alnylam 2030 strategy to accelerate innovation and scale impact to transform human health. For more information, please visit www.alnylam.com or follow Alnylam on X, LinkedIn, Facebook, Instagram, or YouTube.

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, statements regarding: Alnylam's ability to advance the future care of ATTR-CM, including through its efforts to facilitate earlier recognition and diagnosis of ATTR-CM, to improve the quality, consistency and coordination of care for ATTR-CM patients, and to optimize patient outcomes and enable long-term patient impact in ATTR-CM; the potential success of Alnylam's initiatives with Viz.ai and the American Heart Association; and Alnylam's ability to execute on its Alnylam 2030 strategy to accelerate innovation and scale to transform human health, 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 2030 strategy; Alnylam's ability to discover and develop novel drug candidates and delivery approaches and successfully demonstrate the efficacy and safety of its product candidates; the pre-clinical and clinical results for Alnylam's product candidates; the possibility of unfavorable new clinical data and further analyses of existing clinical data; interim and preliminary data; the possibility that clinical data are subject to differing interpretations and assessments by regulatory agencies; actions or advice of regulatory agencies and Alnylam's ability to obtain and maintain regulatory approval for its product candidates, as well as favorable pricing and reimbursement; successfully launching, marketing and selling Alnylam's approved products globally; delays, interruptions or failures in the manufacture and supply of Alnylam's product candidates or its marketed products; obtaining, maintaining and protecting intellectual property; Alnylam's ability to manage its growth and operating expenses through disciplined investment in operations; Alnylam's ability to maintain strategic business collaborations; Alnylam's dependence on third parties for the development and commercialization of certain products; the outcome of litigation; the potential risk of future government investigations; and unexpected expenditures; as well as those risks more fully discussed in the "Risk Factors" filed with Alnylam's 2025 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 other filings that Alnylam makes with the SEC. In addition, any forward-looking statements represent Alnylam's views only as of today and should not be relied upon as representing Alnylam's 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.

Christine Akinc

(Investors and Media)

+1-617-682-4340

Josh Brodsky

(Investors)

+1-617-551-8276

Alnylam Advances Future of ATTR-CM Care Through Strategic Collaboration with Viz.ai and Support for the American Heart Association