Merck Strengthens Expertise in RNAi Technology

Merck & Co., Inc. (Whitehouse Station, NJ, www.merck.com) will purchase Sirna Therapeutics (San Francisco, CA, www.sirna.com), a biotechnology company developing a new class of medicines based on RNA interference (RNAi) technology, for $1.1 billion. The acquisition of Sirna complements the research on RNA expression that Merck has been doing since its 2001 acquisition of Rosetta Inpharmatics, Inc.

Sirna Therapeutics has been at the forefront of efforts to create RNAi-based therapeutics, which could significantly alter the treatment of disease. RNAi-based therapeutics selectively catalyze the destruction of the RNA transcribed from an individual gene. This enables an entirely novel approach to developing drugs with the potential to produce highly specific, potent, and long-lasting effects. Sirna’s lead clinical candidate, Sirna-027, is currently moving into Phase 2 trials for the treatment of the wet form of age-related macular degeneration, in a collaboration with Allergan.

RNAi was discovered in 1998 by Andrew Z. Fire of Stanford University and Craig C. Mello of the University of Massachusetts. Fire and Mello won this year’s Nobel Prize for physiology or medicine for that discovery.

Merck's decision to acquire Sirna will accelerate the development of RNAi-based therapeutics. Under the terms of the agreement, Merck will acquire 100% of the equity of Sirna at a price of $13 per share in cash, making Sirna a wholly owned subsidiary of Merck & Co., Inc. The two companies expect to complete the acquisition in the first quarter of 2007.