Study of Mesenchymal Stem Cells for the Treatment of Medically Refractory Ulcerative Colitis (UC)

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colon and rectum, which continues to increase in incidence for unknown reasons, resulting in a significant burden to the healthcare system. UC is characterized by persistent mucosal inflammation of the colon and rectum with a chronic remitting and relapsing behavior which leaves patients on chronic immunosuppression and hospitalizations to treat the disease symptoms, but unable to cure the disease. Despite the ever-growing armamentarium of immunosuppressive medication, up to 30% of patients still require a colectomy for medically refractory disease. Participants with medically refractory ulcerative colitis will be treated by targeted endoscopic delivery of remestemcel-L, an ex vivo culture expanded allogeneic bone marrow derived mesenchymal stem cell product at a dose of 150 or 300 million. This will be injected into the submucosal layer of the colon and rectal wall. Patients will receive a second dose of remestemcel-L at a dose of 150 or 300 million MSCs (same dose as initial). If at 3 months post injection of remestemcel-L there is clinical remission, escalation of medical management and/or surgery will be delayed and patients observed. If there is worsening or no improvement in treated patients, then patients will proceed with escalation of medical management or colectomy as per standard of care. Control patients without improvement will cross over to receive remestemcel-L at 3 months and may be retreated at 6 months. All patients will be followed for two years post initial treatment. There will be a total of 4 cohorts of 3 patients (2 treatment:1 control) receiving the 150 million MSC dose of study drug and a total of 4 cohorts of 3 patients (2 treatment:1 control) receiving 300 million MSCs dose of study drug. This study plans to enroll a total of 24 participants. The primary endpoint of this study is to determine the safety and feasibility of endoscopic injection of remestemcel-L, an ex vivo culture expanded allogeneic bone marrow derived mesenchymal stem cell product for treatment of medically refractory ulcerative colitis.