A gene therapy for spinal muscular atrophy (SMA) patients is making waves. Novartis (NYSE:NVS) revealed in a press release new long-term data highlighting the durability of Zolgensma (onasemnogene abeparvovec) up to 7.5 years after a single treatment. The data comes from two long-term follow-up studies, LT-001 and LT-002, which examined a range of patient populations…