The 2 deaths, due to acute liver failure, occurred in patients treated in Kazakhstan and Russia.
Editor's Note: This article was updated to reflect new information made available on the age of the patient's involved.
Two children with spinal muscular atrophy (SMA) have died after being treated with onasemnogene abeparvovec (Zolgensma; Novartis) from acute liver failure, a known safety risk of the therapy.1
Novartis has updated the FDA and other regulatory agencies in countries that Zolgensma is approved in, including Russia and Kazakhstan, where the deaths occurred. The company will also update the labeling of Zolgensma to include the deaths.
“While this is important safety information, it is not a new safety signal and we firmly believe in the overall favorable risk/benefit profile of Zolgensma, which to date has been used to treat more than 2300 patients worldwide across clinical trials, managed access programs, and in the commercial setting,” Novartis said in an emailed statement to BioPharma Dive.2
Zolgensma’s labeling includes the risk of liver injury and instructs clinicians to assess liver function before treatment and to manage liver enzyme counts with steroid treatment. The 2 deaths occurred 5 to 6 weeks after the one-time infusion and 1 to 10 days after corticosteroid treatment was tapered, according to an initial report from Stat News.1
New information revealed by Novartis and reported by Bloomberg3 indicates that 1 patient was outside of the FDA-approved max age for treatment that is indicated in the US; however, the patient's age and weight were in alignment with the approved indication in the country of treatment. In the US, the FDA approved treatment with Zolgensma in patients under 2 years of age; the European Union approved it for patients weighing up to 21 kg, which in patients with SMA, can equate to a child up to 5 years old; and in Russia, there is no upward age limit in effect.
An FDA advisory committee meeting that took place last fall identified risks of adeno associated virus (AAV) gene therapies including, specifically, Zolgensma.2 The committee recommended caution, but nothing that would hinder gene therapy development.
Zolgensma, which was approved in the US in May 2019, just recently demonstrated further positive data from SPR1NT (NCT03505099), a phase 3 multicenter, single-arm trial on its effect in presymptomatic children with SMA in 2 articles published in Nature Medicine.4,5
All children in both the type 1 and type 2 cohorts achieved the ability to independently sit and most achieved other age-appropriate milestones including standing and walking. None of the children in the study required respiratory support or nutritional support, and there were no serious treatment-related adverse events observed.
"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," Shephard Mpofu, MD, SVP, chief medical officer, Novartis Gene Therapies, said in a previous statement.6 "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."