Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that it has initiated its DISCOVERY trial, a screening study examining the prevalence of transthyretin (TTR) mutations in patients suspected of having cardiac amyloidosis. With this study, Alnylam aims to identify and facilitate the diagnosis of familial amyloidotic cardiomyopathy (FAC). Alnylam is advancing ALN-TTRsc, an investigational candidate targeting TTR for the treatment of patients with TTR cardiac amyloidosis, including FAC – which is caused by mutations in TTR – and senile systemic amyloidosis (SSA) – which is caused by idiopathic amyloid deposition of wild-type TTR in the heart.

“We believe that ALN-TTRsc has the potential to be an important therapeutic for the treatment of FAC – an underdiagnosed disease with significant morbidity and mortality, and no approved therapies. With the initiation of DISCOVERY, we aim to identify and facilitate the diagnosis of FAC by screening patients suspected of having cardiac amyloidosis for the presence of TTR mutations,” said Pritesh Gandhi, Vice President, Medical Affairs at Alnylam. “We are excited about the potential for ALN-TTRsc for the treatment of patients with TTR cardiac amyloidosis. Our clinical data to date with ALN-TTRsc have demonstrated robust knockdown of circulating TTR – the disease-causing gene – of up to 94%, with a very encouraging safety profile. We believe that ALN-TTRsc holds promise as a potential new therapeutic option for patients with TTR-mediated cardiac amyloidosis.”

DISCOVERY is a prospective, multi-center screening study designed to enroll up to 1,000 patients suspected of having cardiac amyloidosis. The study’s primary objective is to characterize the frequency of TTR mutations. The study’s secondary objective is to further characterize disease features in patients found to have a TTR mutation. Results from DISCOVERY are expected to determine the frequency of TTR mutations in patients with clinical and/or radiological findings of cardiac amyloidosis and identify FAC patients who may be eligible for clinical trials of novel investigational therapeutics such as ALN-TTRsc.

TTR-mediated amyloidosis (ATTR) is an inherited, progressively debilitating, and often fatal disease caused by mutations in the TTR gene. These mutations cause misfolding of the protein and the formation of amyloid fibrils that deposit in tissues. One of the clinical manifestations of ATTR is FAC, in which TTR deposits occur primarily in heart tissue, resulting in cardiomyopathy. Amyloid deposition leads to cardiac wall thickening and heart failure. FAC is fatal within 2.5 to 5 years of diagnosis and treatment is currently limited to supportive care. FAC is an underdiagnosed disease; while the true prevalence is unknown, FAC is estimated to affect at least 40,000 people worldwide. It is predominantly caused by the V122I mutation which is found in up to 4% of the African American population. It is believed that FAC is an important cause of cardiac morbidity and mortality in African Americans over the age of 65.

“FAC is under recognized, and it is our hope that the DISCOVERY study will raise awareness amongst patients and health care professionals of this debilitating and progressive disease,” said Herman Taylor, M.D., Endowed Professor and Director, Cardiovascular Research Institute at Morehouse School of Medicine. “With accurate and earlier diagnosis of FAC, we may have the potential to make an impact in the lives of these patients.”

Alnylam is currently conducting a Phase 2 study of ALN-TTRsc aimed at evaluating the safety, tolerability, pharmacodynamic and preliminary clinical activity of ALN-TTRsc in patients with FAC and SSA. The Phase 2 trial is an open-label, multi-dose study of ALN-TTRsc, designed to enroll approximately 25 TTR cardiac amyloidosis patients with FAC or SSA. The primary objective of the study is to evaluate the safety and tolerability of ALN-TTRsc. The secondary objectives are to assess the pharmacodynamic effect of ALN-TTRsc on serum levels of TTR and characterize the pharmacokinetics of ALN-TTRsc. In addition, a number of exploratory clinical endpoint data are being collected. Alnylam expects to present initial results from the Phase 2 study at a meeting to be held during the American Heart Association meeting in November. Patients completing the Phase 2 trial may be eligible to participate in an open-label extension (OLE) study for further assessment of general tolerability and clinical activity with long-term dosing; the ALN-TTRsc Phase 2 OLE study is on track to be initiated in the coming weeks. Alnylam expects to begin a Phase 3 trial in TTR cardiac amyloidosis patients by the end of 2014. ALN-TTRsc employs an siRNA targeting wild-type and all mutant forms of TTR and utilizes our proprietary GalNAc-conjugate delivery platform which enables subcutaneous delivery of our RNAi therapeutics with a wide therapeutic index.

About ATTR
Transthyretin (TTR)-mediated amyloidosis (ATTR) is an inherited, progressively debilitating, and often fatal disease caused by mutations in the TTR gene. TTR protein is produced primarily in the liver and is normally a carrier of vitamin A. Mutations in TTR cause abnormal amyloid proteins to accumulate and damage body organs and tissue, such as the peripheral nerves and heart, resulting in intractable peripheral sensory neuropathy, autonomic neuropathy, and/or cardiomyopathy. ATTR represents a major unmet medical need with significant morbidity and mortality; familial amyloidotic polyneuropathy (FAP) affects approximately 10,000 people worldwide and familial amyloidotic cardiomyopathy (FAC) is estimated to affect at least 40,000 people worldwide. FAP patients have a life expectancy of 5 to 15 years from symptom onset, and the only approved treatment options for early stage disease are liver transplantation, and tafamidis (approved in Europe). FAC is fatal within 2.5 to 5 years of diagnosis and treatment is currently limited to supportive care. Senile systemic amyloidosis (SSA) is a non-hereditary form of TTR cardiac amyloidosis caused by idiopathic deposition of wild-type TTR; its prevalence is generally unknown, but is associated with advanced age. There is a significant need for novel therapeutics to treat patients with TTR amyloid polyneuropathy and/or cardiomyopathy.

About GalNAc Conjugates and Enhanced Stabilization Chemistry (ESC) GalNAc Conjugates
GalNAc-siRNA conjugates are a proprietary Alnylam delivery platform and are designed to achieve targeted delivery of RNAi therapeutics to hepatocytes through uptake by the asialoglycoprotein receptor. Alnylam’s Enhanced Stabilization Chemistry (ESC) GalNAc-conjugate technology enables subcutaneous dosing with increased potency, durability, and a wide therapeutic index, and is being employed in several of Alnylam’s genetic medicine programs, including programs in clinical development.

About RNAi
RNAi (RNA interference) is a revolution in biology, representing a breakthrough in understanding how genes are turned on and off in cells, and a completely new approach to drug discovery and development. Its discovery has been heralded as “a major scientific breakthrough that happens once every decade or so,” and represents one of the most promising and rapidly advancing frontiers in biology and drug discovery today which was awarded the 2006 Nobel Prize for Physiology or Medicine. RNAi is a natural process of gene silencing that occurs in organisms ranging from plants to mammals. By harnessing the natural biological process of RNAi occurring in our cells, the creation of a major new class of medicines, known as RNAi therapeutics, is on the horizon. Small interfering RNA (siRNA), the molecules that mediate RNAi and comprise Alnylam's RNAi therapeutic platform, target the cause of diseases by potently silencing specific mRNAs, thereby preventing disease-causing proteins from being made. RNAi therapeutics have the potential to treat disease and help patients in a fundamentally new way.

About Alnylam Pharmaceuticals
Alnylam is a biopharmaceutical company developing novel therapeutics based on RNA interference, or RNAi. The company is leading the translation of RNAi as a new class of innovative medicines with a core focus on RNAi therapeutics as genetic medicines, including programs as part of the company’s “Alnylam 5x15™” product strategy. Alnylam’s genetic medicine programs are RNAi therapeutics directed toward genetically defined targets for the treatment of serious, life-threatening diseases with limited treatment options for patients and their caregivers. These include: patisiran (ALN-TTR02), an intravenously delivered RNAi therapeutic targeting transthyretin (TTR) for the treatment of TTR-mediated amyloidosis (ATTR) in patients with familial amyloidotic polyneuropathy (FAP); ALN-TTRsc, a subcutaneously delivered RNAi therapeutic targeting TTR for the treatment of ATTR in patients with TTR cardiac amyloidosis, including familial amyloidotic cardiomyopathy (FAC) and senile systemic amyloidosis (SSA); ALN-AT3, an RNAi therapeutic targeting antithrombin (AT) for the treatment of hemophilia and rare bleeding disorders (RBD); ALN-CC5, an RNAi therapeutic targeting complement component C5 for the treatment of complement-mediated diseases; ALN-AS1, an RNAi therapeutic targeting aminolevulinic acid synthase-1 (ALAS-1) for the treatment of hepatic porphyrias including acute intermittent porphyria (AIP); ALN-PCS, an RNAi therapeutic targeting PCSK9 for the treatment of hypercholesterolemia; ALN-AAT, an RNAi therapeutic targeting alpha-1 antitrypsin (AAT) for the treatment of AAT deficiency-associated liver disease; ALN-HBV, an RNAi therapeutic targeting the hepatitis B virus (HBV) genome for the treatment of HBV infection; ALN-TMP, an RNAi therapeutic targeting TMPRSS6 for the treatment of beta-thalassemia and iron-overload disorders; ALN-ANG, an RNAi therapeutic targeting angiopoietin-like 3 (ANGPTL3) for the treatment of genetic forms of mixed hyperlipidemia and severe hypertriglyceridemia; ALN-AC3, an RNAi therapeutic targeting apolipoprotein C-III (apoCIII) for the treatment of hypertriglyceridemia; ALN-AGT, an RNAi therapeutic targeting angiotensinogen (AGT) for the treatment of hypertensive disorders of pregnancy (HDP), including preeclampsia; and other programs yet to be disclosed. As part of its “Alnylam 5x15” strategy, as updated in early 2014, the company expects to have six to seven genetic medicine product candidates in clinical development - including at least two programs in Phase 3 and five to six programs with human proof of concept - by the end of 2015. The company’s demonstrated commitment to RNAi therapeutics has enabled it to form major alliances with leading companies including Merck, Medtronic, Novartis, Biogen Idec, Roche, Takeda, Kyowa Hakko Kirin, Cubist, GlaxoSmithKline, Ascletis, Monsanto, and The Medicines Company. In early 2014, Alnylam and Genzyme, a Sanofi company, formed a multi-product geographic alliance on Alnylam's genetic medicine programs in the rare disease field. Specifically, Alnylam will lead development and commercialization of programs in North America and Europe, while Genzyme will develop and commercialize products in the rest of world. In addition, Alnylam and Genzyme will co-develop and co-commercialize ALN-TTRsc in North America and Europe. In March 2014, Alnylam acquired Sirna Therapeutics, a wholly owned subsidiary of Merck. In addition, Alnylam holds an equity position in Regulus Therapeutics Inc., a company focused on discovery, development, and commercialization of microRNA therapeutics. Alnylam scientists and collaborators have published their research on RNAi therapeutics in over 200 peer-reviewed papers, including many in the world’s top scientific journals such as Nature, Nature Medicine, Nature Biotechnology, Cell, New England Journal of Medicine, and The Lancet. Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit www.alnylam.com.

Alnylam Forward-Looking Statements
Various statements in this release concerning Alnylam’s future expectations, plans and prospects, including without limitation, Alnylam’s views with respect to the potential for RNAi therapeutics, including ALN-TTRsc for the treatment of FAC and the DISCOVERY trial, its expectations with respect to timing of regulatory filings and the reporting of initial data from a clinical trial for ALN-TTRsc, the potential therapeutic opportunities for ALN-TTRsc, its expectations regarding its “Alnylam 5x15” product strategy, and its plans regarding commercialization of RNAi therapeutics, including ALN-TTRsc, constitute forward-looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including, without limitation, Alnylam’s ability to discover and develop novel drug candidates and delivery approaches, successfully demonstrate the efficacy and safety of its drug candidates, the pre-clinical and clinical results for its product candidates, which may not support further development of product candidates, actions of regulatory agencies, which may affect the initiation, timing and progress of clinical trials, obtaining, maintaining and protecting intellectual property, Alnylam’s ability to enforce its patents against infringers and defend its patent portfolio against challenges from third parties, obtaining regulatory approval for products, competition from others using technology similar to Alnylam’s and others developing products for similar uses, Alnylam’s ability to manage operating expenses, Alnylam’s ability to obtain additional funding to support its business activities and establish and maintain strategic business alliances and new business initiatives, Alnylam’s dependence on third parties for development, manufacture, marketing, sales and distribution of products, the outcome of litigation, and unexpected expenditures, as well as those risks more fully discussed in the “Risk Factors” filed with Alnylam’s most recent Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) 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 its views as of any subsequent date. Alnylam explicitly disclaims any obligation to update any forward-looking statements.