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Phase II clinical trial of regenerative medicine product Stemchymal® -  Recruitment of first patient

REPROCELL is pleased to announce that the first patient has been registered and the test article administered at Nagoya University in the Phase II clinical trial of the regenerative medicine product Stemchymal®.

Stemchymal® aims to tackle an urgent medical need for the treatment of spinocerebellar ataxia, a rare disease which has a major impact on quality of life. It is characterized by slowly progressing incoordination of gait and dysphagia due to the degeneration of nerve cells in the cerebellum, brain stem, and spinal cord. There are approximately 30,000 patients in Japan, and it is an intractable rare disease for which no radical treatment exists at present. Stemchymal® is the first regenerative medicine aiming to inhibit the progression of the disease.

In the Phase II clinical trial, the safety and efficacy of Stemchymal® will be evaluated in patients with spinocerebellar ataxia (SCA3 and SCA6 type). A total of 53 patients will be enrolled in this “Multi-center, placebo-controlled, randomized, double-blind, parallel-group comparison” trial, providing a robust assessment of efficacy.

The clinical trial will be conducted at 10 sites throughout Japan. Contracts with Nagoya University and the National Center of Neurology and Psychiatry have been concluded already, and further sites are being recruited.

The Phase II clinical trial is planned for completion by December 2021, and should the trial be successful, we aim to request an approval promptly thereafter. Since Stemchymal® has been designated as an orphan regenerative medicine product, the review period is expected to be shorter than usual.

In Taiwan, a Phase II clinical trial for spinocerebellar ataxia has already been conducted by Steminent Biotherapeutics Inc. (Steminent). All scheduled patients have completed the administration and their status is being monitored. Also, in the United States, Steminent has received the approval of clinical trial notification (IND) by FDA.

We will continue to progress the Phase II clinical trial of Stemchymal® in Japan with the aim of testing this innovative new therapy in patients as soon as possible.

About inquiries: Please contact us regarding this matter. Please refrain from contacting any universities and hospitals.


Overview of Phase II clinical trial of Stemchymal® in Japan




Multicenter, placebo-controlled, randomized, double-blind, parallel-group comparison (Protocol No.:RS-01)

Target disease

Spinocerebellar ataxia (SCA3、SCA6)

Administration method

3 times (every 4 weeks) by intravenous infusion from a blood vessel in the arm

Evaluation item

  • Primary evaluation item: SARA score
  • Secondary evaluation item: SCAFI, INAS, PGI, CGI, Neurofilament Light chain, NSE, etc.

Number of patients

53 patients (Stemchymal® group: 28 patients, Placebo group: 25 patients)

Implementation period


Number of implementing site

10 sites (planned)



Placebo control: A placebo is an inert substance that resembles the physical properties such as color, weight and taste as closely as possible to the investigational drug but contains no medicinal ingredients. In clinical trials, subjects are divided into two groups: a group that receives the study drug and a group that receives a placebo, so that the effects of the study drug can be appropriately evaluated.

Randomized controlled trial: Patients are randomly divided into the Stemchymal® group and the placebo group to reduce trial bias (e.g. placing more patients with high therapeutic efficacy in the Stemchymal® group or placing patients with low therapeutic efficacy in the placebo group). The level of evidence is higher than in non-randomized controlled trials because each group has a more uniform nature.

Double-blind: A test method that neither the patient nor physician know which drug is being administered. If the trial is conducted while knowing the content of the drug being administered, subjective judgement and placebo effects may be mixed in the assessment, which may result in a loss of objectivity. Double-blind is a method of minimizing the risk of bias in the test results and is known as the most common comparative test to confirm the therapeutic effect and efficacy of a new drug.

Parallel group comparison study: The purpose of this trial is to compare the Stemchymal® group and the placebo group in parallel during observation.


Phase II clinical trial of Stemchymal® in Taiwan

In a Phase I/IIa clinical trial conducted in Taiwan, the safety of intravenous Stemchymal® in patients with spinocerebellar ataxia type 3 (SCA3) has been confirmed, and data suggesting its efficacy have been obtained. Efficacy was assessed using the Scale for the Assessment and Rating of Ataxia (SARA) score for 12 months after a single dose of Stemchymal®, indicating that clinical progression was likely to be suppressed. In four of the six patients, symptom improvement lasted up to 24 weeks after a single dose of Stemchymal®. See the references below for more information.


Jacobi et al. The natural history of spinocerebellar ataxia type 1, 2, 3, and 6 A 2-year follow-up study.  Neurology 77, pp. 1035–1041, PMID: 21832228 (2011).

Tsai et al. Treatment of Spinocerebellar Ataxia With Mesenchymal Stem Cells A Phase I-IIa Clinical Study. Cell Transplantation 26, pp. 503-512, PMID: 28195034 (2017). 

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