Awaiting more data
When asked for comment, Daniel E. Furst, MD, professor of medicine (emeritus) at the University of California, Los Angeles, said “there certainly are neurotropic factors” at play in rheumatology, “so there’s sort of a potential reason why” VNS might work, “but we need to understand far more about its mechanism, and [remember] that open-label studies are not to be believed until” large, randomized, blinded, placebo-controlled studies are done.
Dr. Daniel E. Furst
Dr. Furst also is an adjunct professor at the University of Washington, Seattle, and a research professor at the University of Florence (Italy). He is in part-time practice in Los Angeles and Seattle.
If everything works out, however, “the vagus nerve may give us a much wider opportunity to block a host of cytokines; it may change the whole paradigm of how we manage rheumatoid arthritis. I think this is possibly a groundbreaking new therapeutic area, much in the way the biologics were” 20 years ago, said rheumatologist Norman B. Gaylis, MD.
Courtesy Dr. Norman B. Gaylis
Dr. Norman B. Gaylis discusses VNS device placement with a patient.
Several of the 14 patients in SetPoint’s safety study were enrolled at Dr. Gaylis’s practice in Aventura, Fla., just north of Miami; he said he is eagerly awaiting for the results to be unblinded. If clinical response in that study and others correlates with a cytokine response, “that’s going to be big, and very significant” in the rheumatology community, he said.
SetPoint’s microregulator is charged wirelessly through a collar patients wear for a few minutes once a week. Dosing can also be adjusted through the collar with the help of a computer application.
The device wasn’t turned on in 4 of the 14 patients in the safety study, as a sham control, but shamming was problematic because patients can potentially feel VNS as a buzz or a change in their voice. To get around that potential confounder, both sham and treated patients were told they might or might not feel something during the study.
Implantation takes about an hour, and is much less complex than implanting currently available epilepsy VNS systems, which require implantation of both a power source on the chest wall and wire coils on the vagus nerve.
Cardiac concerns are the main safety issue with VNS, beyond the surgery itself. Cardiac monitoring was done in the safety study to “ensure that we did not cause things like bradycardia, heart block, syncope, etc.” Dr. Chernoff said. So far, they haven’t turned out to be a problem.
Dr. Furst and Dr. Kremer had no relevant disclosures. Dr. Gaylis was compensated by SetPoint for participating in the safety study; he is a consultant and investigator for Electrocore. Dr. Furst and Dr. Gaylis are members of the editorial advisory board for MDedge Rheumatology/Rheumatology News.