AveXis presents AVXS-101 IT data demonstrating remarkable increases in HFMSE scores and a consistent clinically meaningful response in older patients with SMA Type 2

• SMA Type 2 patients between two and five years of age who received Dose B met the primary efficacy endpoint with a remarkable mean increase of 6.0 points in HFMSE scores from baseline to month 12, twice the clinically meaningful threshold, as measured by a validated, widely utilized and highly accepted scale developed specifically for older patients with SMA
   
• Nearly all patients (92%) in this cohort achieved a clinically meaningful ≥3-point increase during the study period, demonstrating a consistent response following gene therapy
   
• Increases observed in HFMSE reflect the preservation of motor neurons connected to key muscle groups impacted in SMA Type 2, allowing for motor development such as trunk control when rolling and sitting, and transitioning from lying to sitting
   
• Adverse events observed in STRONG were consistent with the AVXS-101 IV program; no deaths were reported, and no new signals identified
   
• In response to the partial clinical hold on the AVXS-101 IT program by the FDA in October 2019, AveXis provided data indicating no clinical reports of sensory neuronopathy in 335 patients following IV or IT treatment with AVXS-101; FDA is expected to respond by Q2 2020             

Basel, March 24, 2020 – AveXis, a Novartis company, today announced that new data from the Phase 1/2 STRONG study demonstrated a one-time intrathecal (IT) administration of AVXS-101 in patients ≥2 years and <5 years old with spinal muscular atrophy (SMA) Type 2 who received Dose B (1.2 x 10¹⁴ vg) met the primary efficacy endpoint, achieving a remarkable mean increase from baseline of 6.0 points in the Hammersmith Functional Motor Scale-Expanded (HFMSE), twice the clinically meaningful threshold established in previous SMA studies and reflecting improvement in three to six skills. In addition, nearly all patients (92%) in this group achieved a clinically meaningful ≥3-point increase in HFMSE at any post-baseline visit during the study period, demonstrating a consistent response and a dramatic difference from the natural history control group (P <0.0001). Increases observed in HFMSE reflect the preservation of motor neurons connected to key muscle groups impacted in SMA Type 2, allowing for motor development such as trunk control when rolling and sitting, and transitioning from lying to sitting. In contrast to these findings, according to natural history, untreated SMA Type 2 patients typically experience a steady decline in motor function, and more than 30% die by age 25.¹ These data are being presented today during a virtual Clinical Trial Session conducted by the Muscular Dystrophy Association (MDA), scheduled after the 2020 MDA Annual Conference was cancelled due to COVID-19.