Final Results From Phase 3 Trial of Onasemnogene Reinforce Efficacy for Presymptomatic Spinal Muscular Atrophy
In the SPR1NT (NCT03505099) trial, children with presymptomatic spinal muscular atrophy (SMA) who were treated with onasemnogene (Zolgensma; Novartis Gene Therapies, East Hanover, NJ) achieved age-appropriate motor milestones. Children treated with onasemnogene were able to sit, stand, and walk and had no serious treatment-related adverse events. Participants in this study had 2 or 3 copies of the survival of motor neuron 2 (SMN2) gene.
All children in the trial who had 2 copies of SMN2 were able to sit independently for at least 30 seconds and 79% (11/14) achieved this within the World Health Organization (WHO) window of typical development. Standing independently was achieved by 79%, and 64% walked independently, mostly within the typical range of development.
Among those with 3 copies of SMN2, 93% walked independently (14/15), and 73% were within the WHO window of typical development. All 15 became able to stand alone at least 3 seconds, including 93% (14/15) within the WHO window of typical development.
“The robust data from both the 2- and 3-copy SPR1NT cohorts are being published together for the first time, further supporting the significant and clinically meaningful benefit of Zolgensma in presymptomatic babies with SMA,” said Shephard Mpofu, MD, SVP, chief medical officer, Novartis Gene Therapies. “When treated with Zolgensma prior to the onset of symptoms, not only did all 29 patients enrolled in SPR1NT survive but were thriving—breathing and eating on their own, with most even sitting, standing and walking without assistance.”
No new adverse events were reported. Updates on participants motor function for those participating in a long-term follow up studies will be published in later 2022.
Data from the SPR1NT trial are in significant contrast to the natural history of the most prevalent types of SMA in which most children require permanent ventilation or do not survive past the age of 2 years.