MERCK TO ACQUIRE BIOTECH FIRM FOR $1.1 BILLION

Merck announced it has entered into a definitive agreement under which Merck will acquire Sirna Therapeutics, a U.S.-based biotechnology company and a leader in developing a new class of medicines based on RNA interference (RNAi) technology.

Under the terms of the agreement, Merck will acquire through a merger 100 percent of the equity of Sirna at a price of $13 per share in cash, making Sirna a wholly owned subsidiary of Merck. The transaction has a cash value of approximately $1.1 billion.

Sirna has been at the forefront of efforts to create RNAi-based therapeutics, which selectively catalyze the destruction of the RNA transcribed from an individual gene. This enables an entirely novel approach to discovering drugs with the potential to produce highly specific, potent and long-lasting effects, according to the company. The acquisition of Sirna complements the research on RNA expression Merck has been conducting since the 2001 acquisition of Rosetta Inpharmatics.

Sirna's lead clinical development candidate, Sirna-027, is a chemically optimized, short interfering RNA (siRNA) currently moving into Phase II development for the treatment of wet age-related macular degeneration.

The acquisition is subject to clearance under the Hart-Scott-Rodino Antitrust Improvements Act, approval by the stockholders of Sirna and other customary closing conditions. The two companies expect to complete the acquisition in the first quarter of 2007.