Merck has agreed to acquire Sirna Therapeutics for approximately $1.1 billion. Sirna has been at the forefront of efforts to create RNAi-based therapeutics, medicines 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. The two companies expect to complete the acquisition in the first quarter of 2007. The acquisitio...