Aspen Neuroscience’s stem cell therapy improved Parkinson’s disease symptoms for all eight treated patients after one year, with the San Diego biotech now planning for a pivotal phase 3 trial later this year.
Aspen’s therapy is autologous, turning skin cells from patients into stem cells that are then prompted to become new neurons to be implanted into the brain. Whether given a low dose or a high dose of the Parkinson’s candidate, recently named sasineprocel, patients saw marked improvements in measures of symptom control, motor function and quality of life one year later.
Aspen presented the phase 1/2a data March 18 at the AD/PD 2026 International Conference on Alzheimer’s and Parkinson’s Diseases.
“All the patients are improving, and they’re all improving in a way that’s clinically significant,” Aspen CEO Damien McDevitt, Ph.D., told Fierce Biotech. For example, treatment increased the amount of patients’ daily “good on” time—defined as when they feel their symptoms are best under control—by more than two hours.
“Anything over an hour, an hour and a half, is clinically significant,” McDevitt explained.
Some patients were even able to reduce the amount of levodopa, a dopamine replacement agent used to treat Parkinson’s, that they were taking to manage symptoms. Motor symptoms in Parkinson’s are caused by the progressive loss of dopaminergic neurons, so patients typically take levodopa to supplement their levels of the neurotransmitter.
Reducing levodopa usage is a good indicator that the transplanted neurons are producing dopamine, McDevitt said, and brain imaging also revealed that the cells successfully engrafted and were still alive one year after surgery.
“These findings support our approach of reprogramming a patient’s own cells to wind back the epigenetic clock to a pre‑disease state,” Aspen Chief Medical Officer Revati Shreeniwas, M.D., said in the release. “We’re starting to see the positive clinical impact of rebuilding the neural networks damaged by this debilitating disease.”
Videos of one patient, recorded before treatment and at the one-year mark, were particularly striking to the Aspen team. Before receiving sasineprocel, the patient struggled to stand from a chair, open a door and walk down the hallway, with a low voice and a muted facial expression, McDevitt said. One year after the treatment, he is “like a different person,” rising from the chair and walking straight out the door with a smooth gait.
“It’s night and day,” McDevitt said, with the video making many at the company emotional. “There were a lot of tears.”
Aspen is now poised to engage with the FDA on the design of the phase 3 trial for sasineprocel, which McDevitt said should kick off later this year. The biotech will likely follow the precedent set by Bayer subsidiary BlueRock Therapeutics, which is developing a donor-derived Parkinson’s cell therapy called bemdaneprocel.
Bemdaneprocel is being tested in a randomized, sham-controlled, phase 3 study set to enroll about 102 patients. McDevitt expects the FDA will want a similar trial design for Aspen’s sasineprocel.
“It feels like they’re going to want us to do the sham surgery,” the CEO said, though he hopes it may be possible to use a natural history control arm instead. The surgical procedure itself is minimally invasive and relatively simple for neurosurgeons to perform, he added.
Should the phase 3 succeed and sasineprocel gain approval, McDevitt thinks Aspen can commercialize the therapy itself and use it as a springboard to take the biotech’s stem cell platform to the next level. The California company raised a $115 million series C last November, for which Gilead Sciences’ cell therapy unit Kite Pharma pitched in.
“We’re focused on the brain today, and there are other cell types and diseases we’re interested in, but there’s also opportunity outside of the brain,” McDevitt said. “Anywhere where all you need to do is replace missing cells and get grafts to grow.”
