SUZHOU, China, April 14, 2026 /PRNewswire/ — In April 2026, XellSmart officially launches its multicenter Phase II registrational clinical trial of the “Clinical-Grade, Allogeneic, Off-the-Shelf, iPSC-Derived, Dopaminergic Neural Progenitor Cell Therapy (XS411) for Primary Parkinson’s Disease”. The trial continues to be led by Beijing Tiantan Hospital affiliated to Capital Medical University — a National Center for Neurological Disorders, and is again jointly conducted with Peking Union Medical College Hospital, the Second Affiliated Hospital of Soochow University, and more top-tier hospitals. The advance into Phase II trial in less than one year — from 2025 when the Phase I trial commenced with the first transplantation performed at Beijing Tiantan Hospital, is underpinned by positive Phase I results:
Professor Feng Tao, the leading PI from Beijing Tiantan Hospital, stated:”The Phase I study primarily evaluated safety, tolerability, and early efficacy signals, and we have confirmed preliminarily that this novel therapy is safe and effective.”
Professor Feng Tao further explained the Phase II trial design:”Phase II will adopt a prospective, randomized, standard treatment–parallel controlled design with blinded endpoint assessment. The trial plans to enroll 30 patients aged 50–75 years with a clinically confirmed diagnosis of primary Parkinson’s disease and a disease duration of 5 to 15 years. They will be randomized to the experimental and control groups in a 2:1 ratio.
In the first stage, the experimental group will receive iPSC-derived cell therapy, while the control group will receive standard anti-Parkinsonian pharmacotherapy. All participants will be followed for 12 months to further evaluate the efficacy and safety of the treatment.
After completing the 12-month assessment, the experimental group will continue to be followed for an additional year, up to 24 months post-transplantation. Participants in the control group will undergo a second evaluation and, if eligible, may receive XS411 treatment in subsequent follow-up.
The Phase II trial will further address key scientific questions regarding the efficacy and safety of this stem cell transplantation technology, lay a solid foundation for the Phase III registrational trial, and provide more robust scientific evidence to support the clinical translation of this innovative therapeutic modality.”
Positive Phase I Results
Multiple patients with moderate to severe Parkinson’s disease, who were enrolled in the Phase I registrational trial of XS411 — a clinical–grade, allogeneic, off–the–shelf, iPSC–derived, dopaminergic neural progenitor cell therapy for primary Parkinson’s disease — at Beijing Tiantan Hospital and its collaborative centers, after follow-up, have achieved significant improvements across multiple core motor indicators following a single transplantation of XS411, with no adverse events related to the transplanted stem cells observed.
– In terms of efficacy, multiple follow-up assessments following iPSC-derived cell implantation demonstrated significant improvements in key motor outcomes among enrolled patients relative to pre-transplant baseline. These improvements included the MDS-UPDRS Part III motor score in the “OFF” state, duration of “ON” time without troublesome dyskinesia (favorable “ON” time), and daily quality-of-life scores. The degree of improvement was markedly higher than the internationally accepted threshold for clinically meaningful change. Notably, the “OFF” state describes the period when medication effects subside and patients experience motor impairment, while the “ON” state refers to the phase when medication is effective and patients are able to move relatively freely. Overall, these improvements enable patients to enjoy significantly longer periods of high-quality daily function.
– In terms of objective imaging evidence, 18F-DOPA PET-CT molecular imaging performed after treatment revealed a significant increase in 18F-DOPA uptake in the putamen compared with pre-transplant baseline, demonstrating markedly enhanced signal intensity from newly generated dopaminergic neurons in the putamen. This provides direct imaging evidence that the transplanted cells can effectively survive, engraft, differentiate, and function in the patients’ brain.
– In terms of safety, no adverse events related to transplanted stem cells have occurred in any of the transplanted patients.
The encouraging results from the Phase I clinical trial paved the way for the initiation of Phase II clinical trial, approved by China’s National Medical Products Administration (NMPA) and hospital ethics committees.
Delving into the Mechanism of XS411
iPSC-derived cell therapy refers to a type of regenerative medicine that uses cells produced from induced pluripotent stem cells (iPSCs) to repair, replace, or restore damaged cells and tissues in the body.
This is precisely the technological foundation underlying XellSmart’s XS411 cell therapy. An allogeneic, off–the–shelf, iPSC–derived, dopaminergic neural progenitor cell product, XS411 received clearances in 2025 from both China NMPA and the US FDA to launch registrational clinical trials.
Professor Feng Tao 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.”
This strategy is not entirely novel. As early as the late 20th century, Swedish scientists attempted to transplant dopaminergic neurons derived from fetal brain tissue, with some successful outcomes reported. However, this approach ultimately proved unsustainable for two key reasons: significant ethical concerns, and the extremely limited cell source — treating a single patient required four to five fetal brains, which could never satisfy clinical demand.
iPSC technology has perfectly addressed this ethical issue. This Nobel Prize-winning innovation enables the reprogramming of healthy human somatic cells back to a pluripotent state, which can then be directed to differentiate into physiologically functional target cells such as dopaminergic neural progenitor cells.
Professor Feng Tao stated:”Induced pluripotent stem cell therapy specifically involves reprogramming healthy somatic cells into pluripotent stem cells in vitro by introducing specific transcription factors, and then inducing their differentiation into dopaminergic neural precursor cells. These cells are then transplanted into the putamen region of Parkinson’s patients through minimally invasive surgery”.
After transplantation, the cells can survive long-term and differentiate into dopaminergic neurons, synthesize and secrete dopamine, and repair damaged neural circuits, thereby replacing the degenerated and dead dopaminergic neurons.
A Patient’s Journey
In the corridor of the Movement Disorder Department at Beijing Tiantan Hospital, a letter of gratitude from a Phase I patient stood out.
“I am a Parkinson’s disease patient from northeastern China. As time went by, my condition kept deteriorating. I noticed the team led by Director Feng Tao from the Movement Disorder Disease Department of Tiantan Hospital began to conduct academic research experiments on stem cell transplantation for the treatment of Parkinson’s disease — this rekindled the dying flame of my life and awakened my desire for survival”.
The writer Mr. Zhang is a mid-to-late-stage Parkinson’s disease patient, whose quality of life has undergone a qualitative leap after receiving the Phase I therapy. Formerly, he has been suffering from the condition for more than ten years, troubled by multiple motor and non-motor symptoms. Initially, medication was effective in controlling his condition, but as the disease progressed, the efficacy of the medication became increasingly poor, while the side effects became more pronounced.
Though depressed, Mr. Zhang never gave up. He learned about an international breakthrough in Parkinson’s disease treatment — stem cell therapy — and that Tiantan Hospital was conducting a “registrational clinical trial of human allogeneic iPSC-derived dopaminergic neural progenitor cell injection (XS411) for the treatment of primary Parkinson’s disease”. He signed up without hesitation.
Mr. Zhang told the doctors of the research team:”I truly believe scientific progress will bring hope — I trust the professional team at Tiantan Hospital wholeheartedly, and I am more than willing to contribute my part to medical advancement.”
After rigorous screening, Mr. Zhang met the criteria for enrollment. The surgical procedure caused significantly less damage than he had imagined, as Professor Feng Tao illustrated:
“The entire process was minimally invasive. Most patients can wake up and walk on the same day. The incisions are small, and recovery is quick”.
After the surgery, Mr. Zhang’s physical condition improved significantly. Not only did his motor function see great improvement, but his mood, sleep disturbances, and daytime fatigue also were notably relieved. Mr. Zhang was overjoyed, as the outcomes exceeded his expectations.
Professor Feng Tao further explained: “Mr. Zhang’s situation is not an isolated case — similar improvement trends were observed in all patients enrolled in our study. Some patients reported being able to cook for themselves now, while others noted they could finally easily go up and down stairs. Most notably, the daily duration of their good condition has increased significantly”.
Projection based on the Global Burden of Disease (GBD) database indicates that the number of Parkinson’s disease patients in China may reach 10 million by 2050. From dopamine supplementation to stem cell replacement therapy, and from symptom management to neural repair, this profound transformation in Parkinson’s disease treatment is positioning China at the forefront of iPSC-derived cell therapy development. With the commencement of Phase II clinical trial of XS411, XellSmart, the sponsor, along with Professor Feng Tao and his team, are leading this transformation with their professionalism, compassion and sense of urgency to bring new hope to countless individuals like Mr. Zhang.
CONTACT: [email protected]
