The US Food and Drug Administration (FDA) has lifted the clinical hold on the FORTIS clinical trial that was testing the experimental Pompe disease treatment AT845, according to a press release from Astellas, the developer of the treatment. 

“With that same spirit and focus on patient safety, we look forward to resuming the FORTIS clinical trial and the continued development of AT845 as an important potential new treatment for adults living with [late-onset Pompe disease],” said Ha Tran, the executive medical director of Astellas, in the press release.

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“As always, we are grateful to the patients participating in the FORTIS clinical trial and we remain committed to developing novel therapies for those with a high unmet medical need,” Tran continued. 

FORTIS was a multicenter, open-label, ascending dose phase 1/2 trial that was evaluating the safety, tolerability, and efficacy of 3 doses of AT845 in adult patients with late-onset Pompe disease. It was put on clinical hold by the FDA following a serious adverse event of peripheral sensory neuropathy in 1 patient taking part in the trial. 

The company is now working on completing the trial and on regulatory activities that are needed to continue dosing participants.

AT845 is a novel gene replacement therapy that uses an adeno-associated virus-8 (AAV8) vector under a muscle-specific promotor to deliver a functional copy of the gene coding the lysosomal acid alpha-glucosidase (GAA) enzyme, which is faulty in patients with Pompe disease.

Late-onset Pompe disease is a heterogeneous type of Pompe disease characterized by an onset later than infancy and without severe cardiomyopathy. In this type of disease, myopathy usually progresses more slowly and mainly affects the skeletal muscles. Late-onset Pompe disease is caused by the partial deficiency of the GAA enzyme.  


Astellas announces hold lifted by FDA on FORTIS clinical trial of AT845 investigational treatment for adult patients with late-onset Pompe disease. News release. Astellas; January 20, 2023.

Gene transfer study in patients with late onset Pompe disease (FORTIS). US National Library of Medicine. Updated July 8, 2022. Accessed January 24, 2023.