Background: Recent cost-utility analysis (CUA) models for onasemnogene abeparvovec (Zolgensma®, formerly AVXS-101) in spinal muscular atrophy type 1 (SMA1) differ on key assumptions and results. Objective: To compare the manufacturer’s proprietary CUA model to the model published by the Institute for Clinical and Economic Review (ICER), and to update the manufacturer’s model with long-term follow-up data and some key ICER assumptions. Study design: We updated a recent CUA evaluating value for money in cost per incremental Quality-adjusted Life Year (QALY) of onasemnogene abeparvovec versus nusinersen (Spinraza®) or best supportive care (BSC) in symptomatic SMA1 patients, and compared it to the ICER model. Setting/Perspective: USA/Commercial payer. Participants: Children aged <2 years with SMA1. Interventions: Onasemnogene abeparvovec, a single-dose gene replacement therapy, versus nusinersen, an antisense oligonucleotide, versus BSC. Main outcome measure: Incremental-cost effectiveness ratio and value-based price using traditional thresholds for general medicines in the US. Results: Updated survival (undiscounted) predicted by the model was 37.60 years for onasemnogene abeparvovec compared to 12.10 years for nusinersen and 7.27 years for BSC. Updated quality-adjusted survival using ICER’s utility scores and discounted at 3% were 13.33, 2.85, and 1.15 discounted QALYs for onasemnogene abeparvovec, nusinersen, and BSC, respectively. Using estimated net prices, the discounted lifetime cost/patient was $3.93 M for onasemnogene abeparvovec, $4.60 M for nusinersen, and $1.96 M for BSC. The incremental cost per QALY gained for onasemnogene abeparvovec was dominant against nusinersen and $161,648 against BSC. These results broadly align with the results of the ICER model, which predicted a cost per QALY gained of $139,000 compared with nusinersen, and $243,000 compared with BSC (assuming a placeholder price of $2 M for onasemnogene abeparvovec), differences in methodology notwithstanding. Exploratory analyses in presymptomatic patients were similar. Conclusion: This updated CUA model is similar to ICER analyses comparing onasemnogene abeparvovec with nusinersen in the symptomatic and presymptomatic SMA populations. At a list price of $2.125 M, onasemnogene abeparvovec is cost-effective compared to nusinersen for SMA1 patients treated before age 2 years. When compared to BSC, cost per QALY of onasemnogene abeparvovec is higher than commonly used thresholds for therapies in the USA ($150,000 per QALY).

Spinal muscular atrophy type 1 (SMA1) is a debilitating neurodegenerative disease resulting from survival motor neuron 1 gene (SMN1) deletion/mutation. Onasemnogene abeparvovec (formerly AVXS-101) is a gene therapy that restores SMN production via one-time systemic administration. The present study demonstrates widespread biodistribution of vector genomes and transgenes throughout the central nervous system (CNS) and peripheral organs, after intravenous administration of an AAV9-mediated gene therapy. Two symptomatic infants with SMA1 enrolled in phase III studies received onasemnogene abeparvovec. Both patients died of respiratory complications unrelated to onasemnogene abeparvovec. One patient had improved motor function and the other died shortly after administration before appreciable clinical benefit could be observed. In both patients, onasemnogene abeparvovec DNA and messenger RNA distribution were widespread among peripheral organs and in the CNS. The greatest concentration of vector genomes was detected in the liver, with an increase over that detected in CNS tissues of 300-1,000-fold. SMN protein, which was low in an untreated SMA1 control, was clearly detectable in motor neurons, brain, skeletal muscle and multiple peripheral organs in treated patients. These data support the fact that onasemnogene abeparvovec has effective distribution, transduction and expression throughout the CNS after intravenous administration and restores SMN expression in humans.

Background Spinal muscular atrophy type 1 is a motor neuron disorder resulting in death or the need for permanent ventilation by age 2 years. We aimed to evaluate the safety and efficacy of onasemnogene abeparvovec (previously known as AVXS-101), a gene therapy delivering the survival motor neuron gene (SMN), in symptomatic patients (identified through clinical examination) with infantile-onset spinal muscular atrophy. Methods STR1VE was an open-label, single-arm, single-dose, phase 3 trial done at 12 hospitals and universities in the USA. Eligible patients had to be younger than 6 months and have spinal muscular atrophy with biallelic SMN1 mutations (deletion or point mutations) and one or two copies of SMN2. Patients received a one-time intravenous infusion of onasemnogene abeparvovec (1.1 x 10(14) vector genomes per kg) for 30-60 min. During the outpatient follow-up, patients were assessed once per week, beginning at day 7 post-infusion for 4 weeks and then once per month until the end of the study (age 18 months or early termination). Coprimary efficacy outcomes were independent sitting for 30 s or longer (Bayley-III item 26) at the 18 month of age study visit and survival (absence of death or permanent ventilation) at age 14 months. Safety was assessed through evaluation of adverse events, concomitant medication usage, physical examinations, vital sign assessments, cardiac assessments, and laboratory evaluation. Primary efficacy endpoints for the intention-to-treat population were compared with untreated infants aged 6 months or younger (n=23) with spinal muscular atrophy type 1 (biallelic deletion of SMN1 and two copies of SMN2) from the Pediatric Neuromuscular Clinical Research (PNCR) dataset. Findings From Oct 24, 2017, to Nov 12, 2019, 22 patients with spinal muscular atrophy type 1 were eligible and received onasemnogene abeparvovec. 13 (59%, 97.5% CI 36-100) of 22 patients achieved functional independent sitting for 30 s or longer at the 18 month of age study visit (vs 0 of 23 patients in the untreated PNCR cohort; p<0.0001). 20 patients (91%, 79-100]) survived free from permanent ventilation at age 14 months (vs 6 [26%], 8-44; p<0.0001 in the untreated PNCR cohort). All patients who received onasemnogene abeparvovec had at least one adverse event (most common was pyrexia). The most frequently reported serious adverse events were bronchiolitis, pneumonia, respiratory distress, and respiratory syncytial virus bronchiolitis. Three serious adverse events were related or possibly related to the treatment (two patients had elevated hepatic aminotransferases, and one had hydrocephalus). Interpretation Results from this multicentre trial build on findings from the phase 1 START study by showing safety and efficacy of commercial grade onasemnogene abeparvovec. Onasemnogene abeparvovec showed statistical superiority and clinically meaningful responses when compared with observations from the PNCR natural history cohort. The favourable benefit-risk profile shown in this study supports the use of onasemnogene abeparvovec for treatment of symptomatic patients with genetic or clinical characteristics predictive of infantile-onset spinal muscular atrophy type 1. Copyright (C) 2021 Elsevier Ltd. All rights reserved.

To assess the safety/tolerability, optimal dose, and efficacy of AVXS-101 IT in sitting but non-ambulatory patients with spinal muscular atrophy (SMA).

Evaluate preliminary data from the phase 3 STR1VE (NCT03306277) study investigating efficacy and safety of one-time intravenous infusion of onasemnogene abeparvovec-xioi (formerly AVXS-101) in patients with SMA1.

To assess the cost-effectiveness of both single-dose gene-replacement therapy with AVXS-101 (onasemnogene abeparvovec) and current standard of care (nusinersen) in patients with Spinal Muscular Atrophy Type 1 (SMA1) in Japan.