Bayer has discontinued an early-stage clinical gene therapy for a rare genetic disorder in favor of a similar candidate.
Bayer acquired a pair of adeno-associated virus gene therapies aimed at late-onset Pompe disease as part of its $2 billion acquisition of AskBio in 2020. Pompe disease is a rare, severe autosomal recessive metabolic disease characterized by progressive muscular degeneration.
One of the gene therapies, dubbed ACTUS-101, was already in the clinic at the time of that deal. But the future of the asset looked in doubt in January when Bayer explained it was halting further enrollment in that phase 1 study. A total of seven patients had been enrolled in the trial, according to the federal trials database.
Bayer provided that update in the context of ramping up work on its other Pompe disease gene therapy, dubbed AB-1009. The German pharma took the candidate—which has secured FDA fast track and orphan drug designations—into a phase 1/2 trial in the U.S. earlier this year.
“This investigational gene therapy is being studied for its potential to address the underlying genetic defect and to explore whether it can increase production of the deficient enzyme in patients with Pompe disease,” Tahseen Mozaffar, M.D., director of the UCI Health ALS & Neuromuscular Center and the principal investigator for the AB-1009 program, explained in the January release.
While Bayer had the option to keep both Pompe disease programs running simultaneously, the company confirmed in its fourth-quarter earnings documents (PDF) that ACTUS-101 has now been discontinued.
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Other biopharmas have struggled carrying their Pompe candidates through the clinic. Denali Therapeutics’ enzyme replacement therapy (ERT) was placed on hold by the FDA in December, with the regulator citing concerns about immune reactions in preclinical mouse studies. Back in 2024, Roche abandoned a Pompe gene therapy after weighing up the competitive landscape.
At the time, Roche noted that an established standard of care exists for Pompe disease in the form of various approved ERTs.
“While there are no currently approved gene therapies for Pompe disease, investigational treatments are being evaluated by different organizations,” Roche explained at the time.
Astellas has its own Pompe gene therapy in the works, although that was also placed on clinical hold for the second half of 2022 while the FDA investigated a report of nerve damage in one of the trial’s participants. The regulatory hold was lifted in early 2023.
