SanBio began clinical trials last September for SB623, a therapy that restores motor function to stroke patients up to three years after the stroke. The standard treatment, in contrast, must be administered within four hours of the stroke for it to be effective.
In preclinical studies, motor function improvements were seen one week after administration and returned to near baseline (pre-stroke) levels in six months in rat models, according to Casey Case, Ph.D., vp of research. “The limitations or their potential in humans are not yet known.”
SB623 is not a cell-replacement therapy. “It’s a supportive cell therapy,” Dr. Case emphasizes. It is allogeneic, not autologous, but doesn’t require cyclosporine for immune suppression. It is injected directly into the impaired region, thus permitting lower doses without systemic effects. These cells are naturally eliminated by the body after about one month, although motor function seems to continue to improve. The working hypothesis is that these mesenchymal stem cells promote an environment in which damaged cells recover. “The exact mechanism of action, however, is still an area of active research,” Dr. Case notes.
Six weeks into the Phase I/IIa trial, results appear promising. Dr. Case says that the first two patients have experienced no adverse events, and others are being actively recruited. No information is available yet regarding improvements in motor function. In addition to stroke treatment, it may also be useful in treating other neurological deficits, possibly including traumatic brain injury, Parkinson disease, and spinal cord injury.
The therapy is based upon MSCs from the bone marrow of normal, healthy donors. They are grown and transfected with the plasmid encoding notch1 and, ultimately, are stored cryogenically. Other projects using this same platform are in the early stages of development. SanBio has active developmental partnerships with Teijin Limited and Dainippon Sumitomo Pharma Co.