Astellas Pharma said that a participant in the ASPIRO clinical trial of AT132, who had developed a serious adverse event earlier this month, has passed away.

The Japanese pharma company said that the cause of death is yet to be determined.

The ASPIRO clinical trial is being held in patients with X-linked Myotubular Myopathy (XLMTM), which is a rare genetic neuromuscular disorder.

It is a two-part, global, randomized, open-label ascending dose trial for assessing the safety and preliminary efficacy of the AAV8 vector that contains a functional copy of the MTM1 gene in patients aged less than five years of age.

Following the adverse event reported on 1 September, Astellas Pharma had paused screening and dosing of additional participants in the early-stage gene transfer clinical trial.

The Japanese pharma company said that it is collecting the relevant clinical information and adding them into the ongoing investigation about other serious adverse events observed so far in the ASPIRO clinical trial.

Astellas Pharma said that the deceased person was the first and only participant dosed after 23 December 2020 following the release of the earlier clinical hold by the US Food and Drug Administration (FDA).

The FDA has once again asked the AT132 clinical trial to be put on hold. Astellas Pharma said that it will review the contents of the FDA letter and have further dialogue with regulators on the way forward.

Nathan Bachtell — Senior Vice President and Head of Gene Therapy, Medical and Development at Astellas said: “On behalf of Astellas, we extend our deepest sympathies to the participant’s family.

“We will investigate and review all findings with our independent data monitoring committee, our expert liver advisory panel and the ASPIRO site investigators. We remain committed to the development of AT132 and the XLMTM patient community.”

AT132 was developed by US gene therapy company Audentes Therapeutics, which was acquired for a sum of around $3 billion by Astellas Pharma in December 2019.

  ASPIRO trial, Astellas Pharma, AT132, Audentes Therapeutics, Myotubular Myopathy, Nathan Bachtell, US FDA, USA, XLMTM