Novartis will continue to add siRNA capabilities to its tool belt in a deal worth up to $1 billion. The Swiss pharma acquired DTx Pharma, a San Diego-based biotech with a siRNA therapy that it wants to start testing in patients with Carcot-Marie-Tooth disease Type 1A (CMT1A), a neuromuscular disease that can cause loss of muscle function. There are about 150,000 patients with CMT1A in the US and Europe.