Parkinson Gene Therapy AB-1005 Meets Primary End Point in Phase 1b Trial

Krystof Bankiewicz, MD, PhD

Newly announced 18-month findings from a phase 1b clinical trial (NCT04167540) showed that AB-1005 (AskBio), an investigational gene therapy for patients with Parkinson disease (PD), met its primary objective of safety, with feasible administration to the putamen. Study data are expected to be presented at a scientific meeting next quarter while planning for a phase 2 trial remains ongoing.¹

AB-1005, an adeno-associated viral vector serotype 2 (AAV2) gene therapy, was found to be well tolerated among a cohort of 11 patients with PD, with target putamen coverage of 63% (±2%), exceeding the goal of greater than 50% coverage. Consisting of 5 patients with moderate stage PD and 6 with mild stage PD, no serious adverse events (AEs) were attributed to the therapy.

"We are encouraged by these early data, which show AB-1005 to be well tolerated in this study in patients with mild to moderate Parkinson disease,” Krystof Bankiewicz, MD, PhD, scientific chair of Parkinson’s and MSA at AskBio, said in a statement.¹ "Although there is still much to learn about this early-stage investigational gene therapy, these first findings will inform our work in this space and have the potential to contribute to the clinical advancement of AB-1005 for the treatment of Parkinson disease."

The multi-center, multi-site, parallel assignment, non-randomized trial also evaluates changes in motor symptoms through the Movement Disorder Society’s Unified Parkinson’s Disease Rating Scale and PD Motor Diary self-assessments. Non-motor symptoms of PD and brain dopaminergic network integrity, measured by DaTSCAN, will also be included in the outcomes, which will continue to be assessed for up to 5 years.

AB-1005’s AAV2 contains the human glial cell line-derived neurotrophic factor (GDNF) transgene, which allows for stable and continuous expression of GDNF in localized regions of the brain after direct neurosurgical injection with MRI-monitored convection enhanced delivery. GDNF is a homodimer that is a distantly related member of the transforming growth factor-ß superfamily.

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"People living with Parkinson’s disease deserve options to address their unmet medical need,” Christian Rommel, PhD, member of the Executive Committee of Bayer’s Pharmaceuticals Division and Head of Research and Development, said in a statement.¹ "The positive outcome of the AB-1005 Phase Ib clinical trial is an important step forward in our goal to deliver much-needed treatments in areas where innovation has the potential to make a tremendous impact."

The Phase 1 REGENERATE-MSA-101 study (NCT04680065), a pivotal trial assessing AB-1005 in patients with multiple system atrophy (MSA)-parkinsonian type, had its first patient dosed in November 2023. REGENERATE MSA-101, a randomized, double-blind, placebo-controlled study, is expected to include 9 patients aged between 35-75 years with a clinical diagnosis of MSA-P. Each of these individuals has less than 5 years from their diagnosis, are on stable anti-parkinsonian medication regimen, and can walk a distance of 25 feet with or without an assistive device.

The trial will assess a number of secondary outcomes as well, including MSA symptoms and signs, through the Unified Multiple System Atrophy Rating Scale (UMSARS), and change in striatal dopamine transporter (DaT) binding, using Single Photon Emission Computed Tomography DaT imaging. Additionally, investigators will observe changes in quality of life using the Multiple System Atrophy Quality of Life assessment, a self-reported questionnaire of 40 items.

REFERENCES
1. AskBio phase 1b trial of AB-1005 gene therapy in patients with Parkinson’s disease meets primary end point. News release. Bayer AG. January 4, 2024. Accessed January 5, 2024. https://www.bayer.com/media/en-us/askbio-phase-ib-trial-of-ab-1005-gene-therapy-in-patients-with-parkinsons-disease-meets-primary-endpoint/
2. AskBio announces first patient randomized in phase 1 trial of AB-1005 (AAV2-GDNF) gene therapy for multiple system atrophy-parkinsonian type (MSA-P). News release. AskBio. November 17, 2023. Accessed January 5, 2024.. https://www.prnewswire.com/news-releases/askbio-announces-first-patient-randomized-in-phase-1-trial-of-ab-1005-aav2-gdnf-gene-therapy-for-multiple-system-atrophy-parkinsonian-type-msa-p-301991684.html