XellSmart Launches iPSC Phase II for Parkinson’s Following Encouraging Phase I Results

Key Points

• XellSmart has started a multicenter Phase II registrational trial of XS411 for primary Parkinson’s disease.
• The company reported encouraging Phase I results, including early motor improvements and no stem cell-related adverse events in transplanted patients.
• The Phase II study plans to enroll 30 patients and compare XS411 against standard anti-Parkinsonian drug treatment with blinded endpoint assessment.

XellSmart has launched a multicenter Phase II clinical trial of XS411, an induced pluripotent stem cell (iPSC)-derived dopaminergic neural progenitor cell therapy for primary Parkinson’s disease. The product is allogeneic (donor derived) and off the shelf. The trial is being led by Beijing Tiantan Hospital affiliated to Capital Medical University and is being conducted with Peking Union Medical College Hospital, the Second Affiliated Hospital of Soochow University, and other participating hospitals.

Phase II Trial Design

The Phase II study uses a prospective, randomized, standard treatment-parallel controlled design with blinded endpoint assessment. The trial plans to enroll 30 patients ages 50 to 75 with clinically confirmed primary Parkinson’s disease and a disease duration of 5 to 15 years. Patients will be randomized 2:1 to either the experimental group or control group.

In the first stage, the experimental group will receive XS411, while the control group will receive standard anti-Parkinsonian pharmacotherapy. All patients will be followed for 12 months to assess safety and efficacy. After that, the treatment group will continue follow-up through 24 months post-transplantation. The company says control group participants may receive XS411 later if they remain eligible after a second evaluation.

Phase I Results and Mechanism

XellSmart said multiple patients with moderate to severe Parkinson’s disease in the Phase I trial showed improvement across several motor measures after a single XS411 transplantation. The company also said no adverse events related to the transplanted stem cells were observed.

• The company reported improvement in MDS-UPDRS Part III motor scores in the OFF state.
• It also reported longer ON time without troublesome dyskinesia.
• Daily quality-of-life scores improved relative to pre-transplant baseline, according to the release.
• 18F-DOPA PET-CT imaging showed increased uptake in the putamen after treatment, which the company says supports survival, engraftment, differentiation, and function of transplanted dopaminergic neurons.

XS411 is an iPSC-derived dopaminergic neural progenitor cell product designed to replace neurons lost in Parkinson’s disease. The therapy received clinical trial clearances in 2025 from both China’s NMPA and the FDA.

Professor Feng Tao, the leading PI from Beijing Tiantan Hospital explained: “The central pathological feature of Parkinson’s disease is the progressive degeneration and loss of dopaminergic neurons in the substantia nigra of the brain, resulting in a profound dopamine deficit that leads to tremor, rigidity, bradykinesia, and other motor symptoms.”

“Once dopaminergic neurons are damaged, we replace them with new, healthy cells. This core principle of cell replacement therapy explains the fundamental distinction between stem cell-based therapy and conventional drugs or surgical interventions (such as levodopa-based medications, deep brain stimulation, magnetic resonance-guided focused ultrasound): rather than merely managing symptoms, it repairs impaired neural circuits by replacing degenerating cells with functional, healthy dopaminergic neurons.”

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