AskBio Doses First Patient in Phase 1/2 Gene Therapy Trial for Late-Onset Pompe Disease

AskBio has dosed the first participant in PROGRESS-GT LOPD, a Phase 1/Phase 2 clinical trial evaluating investigational gene therapy AB-1009 for the treatment of late-onset Pompe disease (LOPD).¹ The milestone advances the company’s efforts to develop a potentially durable gene therapy approach for the rare neuromuscular disorder, which continues to present significant unmet medical needs despite the availability of enzyme replacement therapies (ERTs).

AB-1009 is an adeno-associated virus (AAV)-based investigational gene therapy designed to enable sustained production of acid alpha-glucosidase (GAA), the enzyme deficient in patients with Pompe disease.¹ The therapy is being developed by AskBio, a wholly owned and independently operated subsidiary of Bayer AG.¹

The open-label PROGRESS-GT LOPD trial is expected to enroll approximately 12 adult participants across sites in the United States.² Investigators will evaluate the therapy’s safety, tolerability, and preliminary efficacy in patients with LOPD.²

Addressing Long-Term Challenges in Pompe Disease

Pompe disease is a rare inherited lysosomal storage disorder caused by mutations affecting production of GAA, leading to glycogen accumulation in muscle cells.³ In LOPD, patients typically experience progressive skeletal muscle weakness and respiratory decline that worsens over time.³

Although multiple recombinant human GAA enzyme replacement therapies have been approved, clinical limitations remain.¹ Some patients experience declining therapeutic response over time, requiring ongoing infusions and increasing treatment burden.⁴ Researchers have increasingly explored gene therapy approaches as a potential strategy for sustained enzyme production and reduced dependence on chronic ERT administration.

“Current treatment approaches may not fully meet the long-term needs of patients, and ongoing research into potential new options remains critical,” said Tahseen Mozaffar, MD, director of the UCI Health ALS & Neuromuscular Center and principal investigator for the AB-1009 clinical program, in the company announcement.¹

According to AskBio, AB-1009 is designed to address the underlying genetic cause of Pompe disease by enabling continuous endogenous production of GAA following a single administration.¹

Regulatory Momentum Supports Program Development

The investigational therapy has already received both FDA Fast Track and Orphan Drug designations, reflecting regulatory recognition of the significant unmet need in Pompe disease.¹ The FDA also accepted the investigational new drug application for AB-1009 earlier this year.¹

Fast Track designation is intended to facilitate development and expedite review of therapies targeting serious conditions with limited treatment options.⁵ Orphan Drug designation may provide incentives including market exclusivity, tax credits, and regulatory support for therapies addressing rare diseases.⁶

“Reaching this milestone reflects the momentum behind our gene therapy platform and our commitment to working toward improving quality of life for people with rare diseases,” said Canwen Jiang, MD, PhD, chief development officer and chief medical officer at AskBio, in the company statement.¹

The clinical advancement also highlights continued investment in neuromuscular gene therapies, an area that has seen substantial growth across both biotech and pharmaceutical sectors over the past several years.

Gene Therapy Continues Expanding in Rare Disease

AAV-based gene therapies have emerged as a major area of focus in rare genetic disease research, particularly for neuromuscular disorders caused by single-gene mutations.⁷ Developers are increasingly targeting diseases such as Duchenne muscular dystrophy, limb-girdle muscular dystrophy, spinal muscular atrophy, and Pompe disease using viral vector platforms intended to provide long-term protein expression after a single treatment.⁷

Despite growing momentum, challenges remain, including durability of expression, immune responses, manufacturing complexity, and long-term safety monitoring.⁷ Still, industry investment continues to accelerate as companies pursue therapies capable of transforming chronic rare diseases into potentially manageable conditions with one-time administration approaches.

For patients with LOPD, the initiation of the PROGRESS-GT LOPD study represents another step toward evaluating whether gene therapy may offer a more durable alternative to lifelong enzyme replacement treatment.

References

1. First participant dosed in AskBio Phase 1/Phase 2 gene therapy trial of AB-1009 for late-onset Pompe disease (LOPD). (2026, May 11). AskBio Inc. https://www.askbio.com/first-participant-dosed-in-askbio-phase-1-phase-2-gene-therapy-trial-of-ab-1009-for-late-onset-pompe-disease-lopd/ 
2. PROGRESS-GT LOPD: A study to evaluate AB-1009 in adults with late-onset Pompe disease (NCT07282847). (2026). ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT07282847
3. Pompe disease. (2024 Jan 18). National Organization for Rare Disorders. https://rarediseases.org/rare-diseases/pompe-disease/
4. Harlaar, L., Hogrel, J. Y., Perniconi, B., Kruijshaar, M. E., Rizopoulos, D., Taouagh, N., Canal, A., Brusse, E., van Doorn, P. A., van der Ploeg, A. T., Laforêt, P., & van der Beek, N. A. M. E. (2019 Oct 16). Large variation in effects during 10 years of enzyme therapy in adults with Pompe disease. Neurology. https://doi.org/10.1212/WNL.000000000000844
5. Fast Track designation. (2024.) US Food and Drug Administration. https://www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/fast-track
6. Medical products for rare diseases & conditions. (2024). US Food and Drug Administration. https://www.fda.gov/industry/developing-products-rare-diseases-conditions
7. Bulaklak, K., & Gersbach, C. A. (2020 Nov 16). The once and future gene therapy. Nature Communications. https://www.nature.com/articles/s41467-020-19505-2