– New Pre-Clinical Results Presented at Oligonucleotide Therapeutics Society (OTS) Meeting Demonstrate that ALN-AS1 Completely Blocks Production of Toxic Heme Biosynthesis Intermediates that Cause Disease Symptoms and Pathology –
– Additional Pre-Clinical Data Presented at OTS Highlight Continued Advances with Clinically Validated GalNAc-Conjugate Platform for Delivery of RNAi Therapeutics with Subcutaneous Dose Administration and a Wide Therapeutic Index –

CAMBRIDGE, MA, USA I October 8, 2013 I Alnylam Pharmaceuticals, Inc. (ALNY), a leading RNAi therapeutics company, announced today that it is advancing its Development Candidate for ALN-AS1, an RNAi therapeutic targeting aminolevulinate synthase-1 (ALAS-1) for the treatment of hepatic porphyrias including acute intermittent porphyria (AIP). The new pre-clinical research findings, presented at the 9th Annual Meeting of the Oligonucleotide Therapeutics Society being held October 6 – 8, 2013 in Naples, Italy, show that subcutaneous administration of a GalNAc-siRNA targeting ALAS-1 leads to rapid, dose-dependent, and long-lasting knockdown of ALAS-1 mRNA and complete inhibition of the toxic intermediates that mediate the symptoms and pathology of AIP. Based on these findings, including results in non-human primate studies, the company has selected its ALN-AS1 Development Candidate and expects to file an Investigational New Drug (IND) application for this RNAi therapeutic in 2014. ALN-AS1 is part of the company’s “Alnylam 5×15” product development and commercialization strategy, in which the company aims to advance five genetic disease target programs into clinical development, including programs in late stages, by the end of 2015. In addition, the company presented new pre-clinical data with its proprietary, clinically validated GalNAc-siRNA conjugate delivery platform for subcutaneous delivery of RNAi therapeutics with a wide therapeutic index.

“We are very pleased to advance ALN-AS1 as a new Development Candidate in our ‘Alnylam 5×15’ pipeline, with the goal of filing an IND in 2014. Our new pre-clinical data show that subcutaneous administration of ALN-AS1 results in complete suppression of the toxic heme biosynthesis intermediates that cause the symptoms and pathology of AIP,” said Rachel Meyers, Ph.D., Vice President of Research and RNAi Lead Development at Alnylam. “ALN-AS1 now becomes our third RNAi therapeutic utilizing our GalNAc-siRNA conjugate delivery platform to enter development stages, extending our progress with ALN-TTRsc for the treatment of transthyretin-mediated amyloidosis, where we intend to soon initiate a Phase II trial, and ALN-AT3 for the treatment of hemophilia, where we plan on filing our IND by the end of this year. With the recent clinical validation of our GalNAc-siRNA conjugate delivery platform, we have increased confidence that ALN-AS1 could become a transformative therapy for patients with AIP, an ultra-rare genetic disease with enormous unmet medical need. We very much look forward to filing our IND for this program in 2014.”

Hepatic porphyrias, including AIP, are ultra-rare orphan diseases caused by loss-of-function mutations in enzymes involved in heme biosynthesis, leading to accumulation of toxic heme intermediate precursors. In the case of AIP, there are approximately 5,000 patients in the U.S. and Europe that suffer acute, life-threatening porphyria attacks every year; there are approximately 500 patients afflicted with recurrent debilitating attacks, often occurring once per month. Treatment options for AIP patients suffering from an attack are limited, and include the use of heme preparations that show limited efficacy and are associated with a number of complications. Currently, there are no drugs available to prevent attacks from occurring. Alnylam’s approach is to knock down ALAS-1, an enzyme upstream of porphobilinogen deaminase (PBGD), the defective gene in AIP. RNAi-mediated silencing of hepatocyte ALAS-1 could reduce the abnormal production of the toxic heme intermediates, specifically aminolevulinic acid (ALA) and porphobilinogen (PBG), which mediate the symptoms and disease pathology in AIP patients. Alnylam believes that a subcutaneously administered RNAi therapeutic targeting ALAS-1 has the potential to be used as a prophylactic approach to prevent attacks and also as a therapy for acute attacks.

The new research results presented at OTS support the selection of the ALN-AS1 Development Candidate for further advancement toward clinical trials. Specifically, multi-dose administration of a GalNAc-siRNA targeting ALAS-1 led to rapid, dose-dependent, and long-lasting knockdown of the ALAS-1 mRNA in non-human primates, with an ED50 of approximately 1.25 mg/kg. Further, in a rat model of AIP, ALN-AS1 administration at doses as low as 2.5 mg/kg resulted in a complete blunting of phenobarbital-induced over-production of PBG and ALA, the toxic heme intermediates in AIP. The company now plans to initiate IND-enabling studies with the goal of filing an IND in 2014.

In addition, Alnylam scientists presented new pre-clinical data on the pharmacokinetic and pharmacodynamic properties of GalNAc-siRNA conjugates. Results showed that target gene silencing is achieved at very low levels of liver tissue exposure. Specifically, the tissue drug level associated with 50% target gene silencing (EC50) was determined to be 0.1 micrograms of GalNAc-siRNA per gram of liver tissue. This tissue level is about 1000-fold lower than other oligonucleotide platforms, where the EC50 for liver target gene knockdown is reported to be about 100 micrograms per gram of tissue (Yu et al., Biochem Pharmacol 2009;77:910-919). In additional studies, the levels of GalNAc-siRNA loaded into the RNA-Induced Silencing Complex (RISC) were quantified and determined to be 0.001 microgram per gram of liver tissue, which corresponds to about 500 to 1000 siRNA molecules per cell for RNAi-mediated target gene knockdown. The ability of GalNAc-siRNA to achieve target gene knockdown at low tissue exposure underscores the potential for a wide therapeutic index for these RNAi therapeutics.

“This year’s OTS meeting highlights continued progress for oligonucleotide therapeutics, and Alnylam is pleased to be a part of this overall endeavor. We are particularly excited to present our advances with RNAi therapeutics that employ our GalNAc-siRNA conjugate delivery platform for hepatocyte target gene silencing. Indeed, we believe our recent clinical data serve to validate this approach and also confirm a remarkable one-to-one correlation of target knockdown in non-human primate studies as compared with human trials,” said Muthiah (Mano) Manoharan, Ph.D., Senior Vice President of Drug Discovery at Alnylam. “New results presented at OTS highlight the applicability of GalNAc-siRNA conjugates across a broad range of hepatocyte-expressed target genes. Moreover, we have demonstrated that target gene knockdown with GalNAc-siRNA is achieved at tissue drug levels of approximately 0.1 micrograms/gram, representing an approximately 1000-fold improvement in potency as compared with other oligonucleotide therapeutic platforms. We believe that these findings of target gene knockdown at very low tissue exposure could significantly improve the therapeutic index for RNA therapeutics, and underscore our belief that GalNAc-siRNA conjugates represent a best-in-class strategy for systemic RNA therapeutics for liver-expressed disease genes.”

About ALN-AS1

Alnylam is developing ALN-AS1, an RNAi therapeutic targeting aminolevulinate synthase-1 (ALAS-1) for the treatment of porphyria, including acute intermittent porphyria (AIP). AIP is an ultra-rare autosomal dominant disease caused by loss of function mutations in porphobilinogen deaminase (PBGD), an enzyme in the heme biosynthesis pathway that can result in accumulation of toxic heme precursors. Patients with AIP suffer from acute and/or recurrent life-threatening attacks with severe abdominal pain, peripheral and autonomic neuropathy, and neuropsychiatric manifestations. ALN-AS1 is a GalNAc-siRNA conjugate targeting ALAS-1, a liver-expressed, rate-limiting enzyme upstream of PBGD in the heme biosynthesis pathway. Inhibition of ALAS-1 is known to reduce the accumulation of heme precursors that cause the clinical manifestations of AIP. ALN-AS1 has the potential to be a therapy for the treatment of acute porphyria attacks, as well as a prophylactic approach for the prevention of recurrent attacks. The company has identified a Development Candidate and intends to advance ALN-AS1 into the clinic in 2014. Alnylam intends to directly commercialize ALN-AS1 in North and South America, Europe, and other parts of the world, and intends to seek a partner for this program in Japan and other Asian territories.

About Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) is an ultra-rare autosomal dominant disease caused by loss-of-function mutations in porphobilinogen deaminase (PBGD), an enzyme in the heme biosynthesis pathway. Exposure of AIP patients to certain drugs, dieting, or hormonal changes can trigger strong induction of aminolevulinate synthase-1 (ALAS-1), another enzyme in the heme biosynthesis pathway, which can lead to accumulation of heme intermediates upstream of PBGD that precipitate attack symptoms. Patients with AIP can suffer acute and/or recurrent life-threatening attacks with severe abdominal pain, peripheral and autonomic neuropathy, and neuropsychiatric manifestations, and possible death if left untreated. Approximately 5,000 patients in the U.S. and Europe suffer acute porphyria attacks annually, and approximately 500 patients are afflicted with recurrent debilitating attacks. Treatment options for AIP patients suffering from an acute attack are limited; patients are treated with intravenous heme analogues that have a slow onset and can result in severe thrombophlebitis and iron overload. Currently there is no approved prophylactic treatment available to prevent recurrent attacks, which often occur monthly in women associated with menses. There exists a significant need for therapies for AIP patients.

About 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. Research findings demonstrate potent and durable target gene silencing, as well as a wide therapeutic index, with subcutaneously administered GalNAc-siRNAs from multiple “Alnylam 5×15” programs.

About RNA Interference (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 toward genetically defined targets for the treatment of serious, life-threatening diseases with limited treatment options for patients and their caregivers. These include: 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 familial amyloidotic cardiomyopathy (FAC); ALN-AT3, an RNAi therapeutic targeting antithrombin (AT) for the treatment of hemophilia and rare bleeding disorders (RBD); ALN-AS1, an RNAi therapeutic targeting aminolevulinate synthase-1 (ALAS-1) for the treatment of porphyria including acute intermittent porphyria (AIP); ALN-PCS, an RNAi therapeutic targeting PCSK9 for the treatment of hypercholesterolemia; ALN-TMP, an RNAi therapeutic targeting TMPRSS6 for the treatment of beta-thalassemia and iron-overload disorders; ALN-AAT, an RNAi therapeutic targeting alpha-1-antitrypsin (AAT) for the treatment of AAT deficiency liver disease; and ALN-CC5, an RNAi therapeutic targeting complement component C5 for the treatment of complement-mediated diseases, amongst other programs. As part of its “Alnylam 5×15TM” strategy, the company expects to have five RNAi therapeutic products for genetically defined diseases in clinical development, including programs in advanced stages, on its own or with a partner by the end of 2015. Alnylam has additional partnered programs in clinical or development stages, including ALN-RSV01 for the treatment of respiratory syncytial virus (RSV) infection and ALN-VSP for the treatment of liver cancers. The company’s leadership position on RNAi therapeutics and intellectual property have enabled it to form major alliances with leading companies including Merck, Medtronic, Novartis, Biogen Idec, Roche, Takeda, Kyowa Hakko Kirin, Cubist, Ascletis, Monsanto, Genzyme, and The Medicines Company. In addition, Alnylam holds an equity position in Regulus Therapeutics Inc., a company focused on discovery, development, and commercialization of microRNA therapeutics. Alnylam has also formed Alnylam Biotherapeutics, a division of the company focused on the development of RNAi technologies for applications in biologics manufacturing, including recombinant proteins and monoclonal antibodies. Alnylam’s VaxiRNA™ platform applies RNAi technology to improve the manufacturing processes for vaccines; GlaxoSmithKline is a collaborator in this effort. Alnylam scientists and collaborators have published their research on RNAi therapeutics in over 100 peer-reviewed papers, including many in the world’s top scientific journals such as Nature, Nature Medicine, Nature Biotechnology, Cell, the 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.

SOURCE: Alnylam Pharmaceuticals