Stemchymal® Therapy

Stemchymal® was developed by Steminent Biotherapeutics Inc. (Headquarters: Taipei City, Taiwan). Mesenchymal stem cells are extracted from adipose tissue collected from healthy donor individuals, further cultured, and then manufactured. Finally, it is diluted with saline and administered via intravenous infusion as a regenerative medicine product.

Treatment Concept

The cell suspension is diluted with saline and administered intravenously.

Mechanism of Action

Therapeutic Indications

Spinocerebellar Ataxia

Spinocerebellar ataxia is a neurological disorder characterized by symptoms such as unsteadiness while walking, hand tremors, and slurred speech. The condition is characterized by the inability to perform smooth movements, despite the ability to move. It primarily refers to a pathological state where the cerebellum, a part of the brain located at the lower back of the head, is affected. Spinocerebellar ataxia is not a single disease, but a collective term for degenerative diseases that cause ataxia-like symptoms as described above^[1].

Approximately one-third of individuals with spinocerebellar ataxia have a hereditary form. The hereditary types are further divided based on the mode of inheritance into autosomal dominant (dominant inheritance) and autosomal recessive (recessive inheritance) forms^[1].

[1] See Spinocerebellar degeneration on the National Center for Rare Diseases website (Japanese language).

Status of Development Progress

The development of Stemchymal® is being carried out globally in Japan, Taiwan, the United States, and South Korea. In Japan, REPROCELL is exclusively leading the development, while in Taiwan and the United States, Steminent Inc. is at the forefront. In South Korea, SCM Life Science is exclusively developing the product.

Status of Development Progress in Japan

Phase II Clinical Trial

In November 2019, a Phase II clinical trial was initiated in Japan for patients with Spinocerebellar Ataxia Type 3 (SCA3) and Type 6 (SCA6), and it was completed in May 2022, including the observation period for all participants. Regarding safety, no serious adverse events were observed in any of the participants, confirming the safety of the treatment. When evaluating efficacy using the primary endpoint, the SARA score^[2], it was confirmed that the increase in SARA score in the treatment group was suppressed compared to the natural progression. Furthermore, statistical analysis of the changes from baseline (Visit 2, before administration) to Week 52 (Visit 8) showed that in the subset with a baseline score of 11 or higher, the treatment group showed a statistically significant improvement compared to the placebo group (P = 0.042).

In Japan, it was designated as a regenerative medicine product for rare diseases in December 2018. As a result, the product is eligible for support measures such as grants covering up to 50% of the development costs, preferential tax incentives, and priority review. REPROCELL is working on preparing the approval application to deliver new treatments to patients fighting diseases as quickly as possible.

The information about this clinical trial is published on JRCT (jRCT2043190090).

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Designated as an orphan drug^[3]

In December 2018, Stemchymal® was designated as a regenerative medicine product for rare diseases with approval from the Minister of Health, Labour and Welfare. As a result, the product is eligible for government support measures, including development grants, tax incentives, and priority review.

Steminent Inc. has been certified as a foreign manufacturer of regenerative medicine products^[4]

In November 2024, Steminent Inc. was certified as a foreign manufacturer of regenerative medicine products by the Minister of Health, Labour and Welfare. This certification is a key requirement for future manufacturing and marketing approvals.

[2] The SARA score is a widely used indicator for evaluating the symptoms of spinocerebellar ataxia. It quantitatively assesses various functions, including walking, standing, speech, and finger movements. The score ranges from 0 to 40 points, with the score increasing as symptoms worsen.

[3] "Orphan drug," also known as a rare disease drug, refers to a medication that is designated by the Minister of Health, Labour and Welfare based on Article 77-2 of the Pharmaceutical and Medical Device Act. It must meet certain criteria, including: having fewer than 50,000 patients in Japan, being of high medical necessity, having sufficient evidence for its use in the target disease, and having a feasible development plan. The designation is made after consulting the Pharmaceutical and Food Safety Council.

[4] A foreign manufacturer that intends to produce regenerative medicine products, etc., to be exported to Japan is referred to as a "regenerative medicine foreign manufacturer" under the Pharmaceutical and Medical Device Act (hereinafter referred to as "the Act"). Similar to domestic manufacturers, foreign manufacturers must be certified under Article 23-24 of the Act, and this certification is a requirement for obtaining the manufacturing and marketing approval for the regenerative medicine products in Japan.

Status of Development Progress in Taiwan and USA

The Phase II clinical trial in Taiwan has been completed

Steminent has been advancing clinical development for Spinocerebellar Ataxia in Taiwan and the United States. First, in Taiwan, from May 2012 to January 2014, a Phase I/IIa clinical trial was conducted to confirm the safety of a single dose of Stemchymal® and gather data suggesting its efficacy. Following that, a Phase II clinical trial was carried out starting in September 2015 to confirm the safety and efficacy of three doses, and this trial was completed in 2020.

In this trial, no safety issues were observed. Additionally, the increase in the SARA score in the treatment group was suppressed compared to the natural history. Furthermore, in the subgroups with higher baseline SARA scores, statistical analysis of changes in the SARA score showed that the treatment group demonstrated significant improvement compared to the placebo group. These results are similar to those obtained in Japan, supporting the data from the Japanese trial.

In the USA, the IND (Investigational New Drug) approval and Orphan Drug designation for the Phase II clinical trial were granted

In the United States, in July 2018, the Investigational New Drug (IND) application for the Phase II clinical trial was approved by the Food and Drug Administration (FDA). Stemchymal® has been granted Orphan Drug designation by the FDA, which promotes the development of drugs for rare diseases.