Astellas Halts DMD Gene Therapy Programs, Incurs $170M Impairment Loss

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Recently, after reviewing the data of Duchenne muscular dystrophy (DMD) gene therapy, Astellas decided to abandon the candidate DMD gene therapy, which resulted in a $170 million impairment loss.

In 2019, Astellas spent $3 billion to acquire gene therapy startup Audentes Therapeutics. Previously, Audentes collaborated with Nationwide Children’s Hospital to obtain relevant preclinical evidence showing that its AAV vector-encoded modified U7 small nuclear RNA could improve muscle function.

Based on these data, Audentes began gene therapy trials in 2020 for boys carrying DMD-related gene mutations (exon 2 duplication). However, after reviewing the results of a preclinical study, Astellas decided to terminate the development of the clinical-stage gene therapy AT702, as well as two early-stage candidate gene therapies, AT751 and AT753, the latter two being applicable to DMD patients suitable for exon 51 and exon 53 skipping therapies.

It is reported that the termination of the above-mentioned DMD gene therapy will result in a $170 million impairment loss for Astellas, which will be reflected in the first quarter financial results of the fiscal year 2022.

Notably, a year ago, the leading gene therapy AT132 faced clinical suspension due to multiple patient deaths in a Phase 2/3 clinical trial, resulting in a $540 million impairment loss for Astellas. AT132 is Audentes' core asset, designed to treat X-linked myotubular myopathy (XLMTM).

It is reported that AT132 uses the AAV8 vector to deliver a copy of the myotubularin 1 gene into patients' muscle cells, improving XLMTM, a neonatal neuromuscular disease caused by MTM1 gene mutations. According to public reports, between May 2020 and September 2021, four patients died after receiving AT132 treatment.

In the statement disclosing the termination of the DMD gene therapy project, Astellas also revealed that it would record and reassess losses related to AT132. In September of last year, Astellas voluntarily suspended patient screening and dosing treatments after a patient receiving a lower and presumably safer dose of AT132 developed liver issues. Weeks later, following the death of the fourth patient, the U.S. FDA placed AT132 under clinical hold. Considering the clinical delays and potential labeling of the marketed product, Astellas stated it would record impairment losses associated with AT132.

According to the announcement, Astellas has also terminated two other projects. One is the DNA vaccine ASP2390, which is in Phase 1 clinical trials for the prevention of dust mite-induced allergic rhinitis; the other is the GITR agonist antibody ASP1951, which is in Phase 1 clinical trials for cancer treatment. Overall, regarding AT132 and the aforementioned two projects, Astellas recorded impairment losses amounting to $390 million in the fourth quarter of the fiscal year 2021.

Reference Source:

1、Astellas takes $170M hit as DMD gene therapy plan unravels in wake of preclinical data

2、Notice Regarding Impairment Loss for Products under Development