Mechanism of MSC Benefit Incompletely Documented
In patients with progressive MS, there is an urgent need for more and better therapies. MSCs, which reside primarily in bone marrow but can be found in other tissues, have been associated with immunomodulatory as well as neuroprotective effects in experimental studies, but whether one or the other or both of these activities are responsible for the clinical benefits observed so far is unresolved.
Others evaluating MSCs in the experimental setting have shown that these “produce a variety of soluble factors with immunomodulatory, neuroprotective, and repair-promoting properties,” said Jeffrey A. Cohen, MD, who was asked to comment on the findings. Dr. Cohen is director of the experimental therapeutics program at the Mellen Center for Multiple Sclerosis, Cleveland Clinic. He said that previous experimental work has encouraged clinical studies, including the work presented by Dr. Karussis.
While the late-breaker presentation provided data suggesting “persistent potent efficacy with good safety and tolerability,” Dr. Cohen pointed out that “the results from this group are substantially better than those reported by several other groups.” He called the difference in results “uncertain,” suggesting that more work is needed to prove that clinical benefit is reliably achieved.
“I think it is too early to tell if MSC transplantation is going to be useful. Other than [the data] reported by the Karussis group, the results have been rather disappointing,” Dr. Cohen said.
Dr. Karussis reports no potential conflicts of interest.