Alnylam Receives Allowance from European Patent Office for Tuschl II Patent, Exclusively Licensed from Max Planck Society.

- Tuschl II Patent in Europe Covers Compositions, Methods, and Uses of Small Interfering RNAs in World's Second Largest Pharmaceutical Market -

- Tuschl II Patent also Granted in Australia -

CAMBRIDGE, Mass. & MUNICH, Germany -- Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that a key fundamental patent from its exclusively held "Tuschl II" patent estate has received Rule 51(4) EPC notification from the European Patent Office (EPO); this notification is equivalent to a "Notice of Allowance" by the United States Patent and Trademark Office. It is expected that the patent will be granted by the EPO within the next six months. The European patent (EP 1407044 or "'044 Patent") broadly covers compositions, methods, and uses of small interfering RNAs (siRNAs), the molecules that mediate RNAi. Alnylam also announced today that the Tuschl II patent has been granted in Australia (AU2002235744). The Tuschl II patent family is exclusively licensed to Alnylam for RNAi therapeutics on a worldwide basis through an agreement with Max Planck Innovation GmbH, the licensing agent for the Max Planck Society.

The '044 patent stems from groundbreaking research published in 2001 in the journal Nature by Thomas Tuschl, Ph.D., a founder of Alnylam, together with other co-inventors in work performed at the Max Planck Institute in Goettingen, Germany. This research led to the first peer-reviewed published evidence that RNAi is mediated by small double-stranded RNAs with defined structural features and that synthetic siRNAs, with or without chemical modification, can be used to achieve RNAi in mammalian cells. Patents stemming from the Tuschl II patent series have been issued or granted in many countries across the world, including the U.S. (U.S. Patent No. 7,056,704 and U.S. Patent No. 7,078,196), New Zealand (NZ525888), South Africa (ZA2003/3929), and Singapore (SG96891); additional applications are pending worldwide, including certain divisional applications in the U.S.

The Tuschl II patent series is distinct in ownership and inventorship from the so-called "Tuschl I" patent series that has yet to issue and for which Alnylam also has a license.

"With growing interest across the entire biopharmaceutical industry in the development of RNAi therapeutics as a potential new class of innovative medicines, the very unique position of Alnylam's intellectual property estate is yet again extended with the advancement today of the Tuschl II patent in Europe and Australia," said John Maraganore, Ph.D., President and Chief Executive Officer of Alnylam Pharmaceuticals. "Importantly, the new patents include claims covering compositions, methods, and uses of siRNAs, thereby providing significant scope for intellectual property needed for development and commercialization of RNAi therapeutics."

"It is perhaps no surprise that the pioneering contributions of Professor Tuschl's work performed here at the Max Planck Institute are so clearly recognized by patent offices around the world. Tuschl II is one of the most valuable patents on RNAi and one of the most promising patents in our patent portfolio. Indeed, scientists have broadly heralded the importance of this published research, which is widely cited in virtually all publications in the RNAi field," said Dr. Joern Erselius, Managing Director of Max Planck Innovation GmbH. "We are pleased to have Alnylam as a partner for the commercialization of this discovery, as they've demonstrated a commitment to the technology's advancement in an unparalleled fashion."

The claims for the European '044 patent cover the compositions, methods, and uses of double-stranded RNAs having key structural elements that are widely recognized as important for the therapeutic activity of siRNAs, including:

* a double stranded region formed from two RNA strands with a length of 19-23 nucleotides;

* one or more 3'-overhangs at the ends of the double-stranded molecule;

* compositions with chemical modifications on the 3'-end of the siRNA to protect against degradation and/or the use of one or more nucleotide modification, such as 2'-O-Me or 2'-F, without any limitation to the number of such modifications; and,

* the use and pharmaceutical compositions of such an siRNA molecule to modulate the function of mammalian or pathogen-derived genes both in vitro and in vivo.

"The claims of the '044 patent broadly cover siRNAs including those with extensive chemical modifications referred to by some as 'siNAs' and the use of siRNAs to silence any and all mammalian and pathogen-derived genes," said Robert Millman, Chief Intellectual Property Counsel of Alnylam Pharmaceuticals. "We are certainly delighted with this advancement in Europe and Australia, and we continue to expect important new patents to emerge from this fundamental patent series that Alnylam has exclusively licensed from the Max Planck Society and from other patent elements that we have consolidated in the RNAi field."

The claims of the Tuschl II '044 patent are provided on the company's website, together with other granted, allowed or issued claims from other Alnylam owned or licensed patents.

About Alnylam Intellectual Property (IP)

Alnylam's IP estate includes issued, allowed, or granted fundamental patents in many of the world's major pharmaceutical markets that claim the broad structural and functional properties of synthetic RNAi therapeutic products. As it applies to the U.S. and Europe, these include:

* the Crooke Patents (U.S. Patent Nos. 5,898,031 and U.S. 6,107,094) licensed exclusively to Alnylam for RNAi therapeutics, which cover compositions, methods, and uses of modified oligonucleotides to inactivate a target mRNA mediated by a double-stranded RNase;

* the Tuschl II '704 patent (U.S. Patent No. 7,056,704) issued in June 2006 and exclusively licensed to Alnylam, which broadly covers methods of making siRNAs to silence any and all disease targets;

* the Tuschl II '196 patent (U.S. Patent No. 7,078,196) issued in July 2006 and exclusively licensed to Alnylam, which broadly covers methods of making siRNAs with or without chemical modifications;

* the Kreutzer-Limmer I '623 patent (EP 1144623) granted in August 2002, upheld in June 2006 and owned by Alnylam, covering methods, medicaments, and uses of siRNAs having, among other structural features, a length of 15-21 base pairs;

* the Kreutzer-Limmer I '945 patent (EP 1214945) granted in June 2005 and owned by Alnylam, covering compositions, methods, and uses of siRNAs with a length between 15 and 49 nucleotides;

* the Tuschl II '044 patent (EP 1407044) granted in July 2007 and exclusively licensed to Alnylam, which broadly covers compositions, methods, and uses of siRNAs;

* additional fundamental patents and patent applications licensed to Alnylam on an exclusive or non-exclusive basis, including those of Fire and Mello (U.S. Patent No. 6,506,559) and Glover et al. (EP 1230375); and,

* several divisional patent applications pending of the aforementioned issued or granted patents and additional patent applications pending including Tuschl I.

In addition to fundamental patents, Alnylam is the exclusive licensee in the field of RNAi therapeutics for more than 150 issued chemistry patents owned or controlled by Isis Pharmaceuticals, Inc., covering chemical modifications of oligonucleotides, including RNAi therapeutics. These patents include:

* phosphorothioate and 2'-O-methyl modifications of oligonucleotides (Buhr, U.S. Patent No. 6,476,205); and,

* 2'-Ribose modifications of oligonucleotides (Cook, U.S. Patent Nos. 5,670,633; 6,005,087; 6,531,584; and 7,138,517).

In addition to fundamental and chemistry patents, Alnylam is the exclusive licensee in the field of RNAi therapeutics for certain delivery patents, including those owned or controlled by Tekmira Pharmaceuticals, Inc., covering delivery of oligonucleotides, including RNAi therapeutics, with liposomal formulations.

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. RNAi therapeutics target the cause of diseases by potently silencing specific messenger RNAs (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 applying its therapeutic expertise in RNAi to address significant medical needs, many of which cannot effectively be addressed with small molecules or antibodies, the current major classes of drugs. Alnylam is leading the translation of RNAi as a new class of innovative medicines with peer-reviewed research efforts published in the world's top scientific journals including Nature, Nature Medicine, and Cell. The company is leveraging these capabilities to build a broad pipeline of RNAi therapeutics; its most advanced program is in Phase II human clinical trials for the treatment of respiratory syncytial virus (RSV) infection. In addition, the company is developing RNAi therapeutics for the treatment of influenza, hypercholesterolemia, and liver cancers, amongst other diseases. The company's leadership position in fundamental patents, technology, and know-how relating to RNAi has enabled it to form major alliances with leading companies including Merck, Medtronic, Novartis, Biogen Idec, and Roche. The company, founded in 2002, maintains global headquarters in Cambridge, Massachusetts. For more information, visit www.alnylam.com.

About Max Planck Innovation

Max Planck Innovation advises and supports scientists of the Max Planck Society in evaluating inventions and filing patent applications. Max Planck Innovation markets patents and technologies to industry and coaches founders of new companies based on research results from Max Planck Institutes. Every year, Max Planck Innovation evaluates about 130 inventions, of which about 70 lead to the filing of a patent application. In the last five years alone, Max Planck Innovation advised 28 spin-offs, completed more than 450 license deals and generated proceeds of more than 100 million Euros for inventors, institutes, and the Max Planck Society. Max Planck Innovation operated under the name of Garching Innovation until October 2006.

Alnylam Forward-Looking Statements

Various statements in this release concerning our future expectations, plans and prospects, including our views with respect to the timing and the future issuance of patents, the importance and scope of our intellectual property rights, and funding from our partners and licensees, 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 risks related to: our approach to discover and develop novel drugs, which is unproven and may never lead to marketable products; obtaining, maintaining and protecting intellectual property utilized by our products; our ability to enforce our patents against infringers and to defend our patent portfolio against challenges from third parties; our ability to obtain additional funding to support our business activities; our dependence on third parties for development, manufacture, marketing, sales and distribution of products; the successful development of our product candidates, all of which are in early stages of development; obtaining regulatory approval for products; competition from others using technology similar to ours and others developing products for similar uses; our dependence on collaborators; and our short operating history; as well as those risks more fully discussed in the "Risk Factors" section of our most recent quarterly report on Form 10-Q on file with the Securities and Exchange Commission. In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. We do not assume any obligation to update any forward-looking statements.