Aspen’s sasineprocel shows motor improvements in Phase I/IIa Parkinson’s disease trial

Aspen Neuroscience, a San Diego–based clinical-stage regenerative medicine company, announced 12-month data from its Phase I/IIa ASPIRO clinical trial evaluating sasineprocel (ANPD001), an autologous iPSC-derived dopaminergic neuron precursor cell therapy, in patients with Parkinson’s disease. The Aspen Neuroscience ASPIRO data, presented as a late-breaking oral presentation at the AD/PDTM 2026 International Conference on Alzheimer’s and Parkinson’s Diseases in Copenhagen, showed numerical improvements across motor function, patient-reported outcomes, and quality of life in eight treated patients — without requiring immunosuppression.

The ASPIRO results

The ASPIRO trial (NCT06344026) is a first-in-human, open-label, multi-center Phase I/IIa study evaluating the safety, tolerability, and preliminary efficacy of sasineprocel in Parkinson’s disease patients aged 50 to 70. The study’s primary endpoint is safety and tolerability of bilateral intracranial administration of autologous iPSC-derived dopaminergic neuron precursor cells (DANPCs) into the post-commissural putamen. Secondary endpoints assess changes in clinician- and patient-reported Parkinson’s-specific clinical outcomes.

Eight patients were treated across two dosing cohorts: four received a low dose of 5 million cells per hemisphere, and four received a higher dose of 5 to 10 million cells per hemisphere. All procedures used MRI-guided delivery via an occipital surgical approach, and clinical outcomes were assessed every six months after transplantation.

At 12 months, both cohorts demonstrated numerical improvements across several measures. Mean Good ON time — the period during which patients experience adequate symptom control — increased by 2.1 hours in the low-dose group and 2.4 hours in the high-dose group. Mean MDS-UPDRS Part III OFF scores, a standard measure of motor function when medication effect has worn off, decreased by 15.5 points in the low-dose cohort and 13.5 points in the high-dose cohort. MDS-UPDRS Part II scores, which capture motor aspects of daily living, improved by 5.3 points and 2.3 points in the low- and high-dose groups, respectively. PDQ-39 quality-of-life scores improved by 51.6% in the low-dose group and 28.5% in the high-dose group. Several patients achieved these improvements while also reducing their levodopa equivalent daily dose (LEDD).

PET imaging confirmed cell survival and engraftment of sasineprocel. No serious surgical adverse events, severe graft-induced dyskinesia, symptomatic hemorrhages, or infarctions were observed, the company said.

These results must be interpreted with caution. The trial enrolled only eight patients, used an open-label design with no control arm, and followed subjects for 12 months — a relatively short window for a neurodegenerative condition. Placebo and expectation effects are well documented in Parkinson’s surgical trials, and without a sham-surgery control, the contribution of the therapy itself to the observed improvements cannot be isolated.

Development context and next steps

Aspen’s chief medical officer, Revati Shreeniwas, stated the company plans to advance sasineprocel into a Phase III study later in 2026. The company did not disclose specific design parameters for the planned registrational trial, including whether it would incorporate a sham-surgery control arm — a design element that has been a subject of debate in the Parkinson’s cell therapy field.

Sasineprocel has received Fast Track designation from the US FDA, which provides more frequent interactions with the agency and eligibility for priority review if certain criteria are met. The designation does not alter the evidentiary standard required for approval.

How Autologous Neuron Transplant Differs from Standard Care

The standard of care for Parkinson’s disease remains pharmacological dopamine replacement, primarily with levodopa/carbidopa combinations. While effective at managing motor symptoms, levodopa does not slow neurodegeneration and is associated with motor fluctuations and dyskinesia over time. Deep brain stimulation (DBS) offers symptomatic relief for patients with medication-refractory motor fluctuations but similarly does not modify the underlying disease course.

Sasineprocel represents a fundamentally different modality. As an iPSC dopamine neuron therapy, it aims to replace the dopaminergic neurons lost to disease rather than supplement the neurotransmitter they produce. The autologous approach — deriving cells from each patient’s own skin fibroblasts, reprogramming them into iPSCs, and differentiating them into DANPCs — eliminates the need for chronic immunosuppression, which is required in allogeneic cell therapy approaches that use donor-derived cells. The company also notes that its approach does not require permanent implantable hardware, distinguishing it from DBS.

Whether this Parkinson’s cell therapy can deliver durable, disease-modifying benefit remains unproven. The 12-month MDS-UPDRS Part III OFF improvements of 13.5 to 15.5 points are numerically notable — for context, a change of approximately 3.25 points on this scale is considered clinically meaningful — but cross-trial comparisons are limited by differences in study design, patient populations, and the absence of blinding in the ASPIRO trial.

The competitive landscape for iPSC dopamine neuron therapy

The field of cell-based therapies for Parkinson’s disease has seen renewed activity after decades of intermittent progress. Allogeneic approaches using fetal-derived or embryonic stem cell–derived dopaminergic neurons are in development at several academic centers and companies, though none has yet reached late-stage clinical testing. BlueRock Therapeutics, a Bayer subsidiary, has been evaluating bemdaneprocel, an allogeneic embryonic stem cell–derived dopaminergic cell therapy, in a Phase I trial. That program requires immunosuppression, a key differentiator from Aspen’s autologous approach.

The autologous neuron transplant approach pursued by Aspen carries distinct manufacturing challenges, including the need to produce an individualized product for each patient from a skin biopsy, with quality assessment at each stage. The company states it uses proprietary machine-learning-based genomics tests to evaluate cell quality throughout manufacturing. Scalability and cost of this personalized manufacturing process will be factors in any future commercialization.