NATIONAL HARBOR, MD—High-dose immunosuppressive therapy and autologous hematopoietic cell transplantation induces a high rate of remission among patients with highly active relapsing-remitting multiple sclerosis (MS), according to data presented at the 2016 CMSC Annual Meeting. Furthermore, that remission is sustained for five years without maintenance therapy. "We saw about 70% long-term, disease-free survival at five years," said Richard A. Nash, MD, a physician at Colorado Blood Cancer Institute in Denver and a HALT-MS investigator.
Richard A. Nash, MD
“What we studied was high-dose therapy, followed by transplant, for treatment of patients with poor-prognosis MS,” said Dr. Nash on behalf of his study collaborators. Their hypothesis was that intensive immunosuppressive therapy followed by transplant would arrest MS disease activity. Their phase II multicenter study had a prospective, open-label, single-arm design. There were three centers involved—Baylor College of Medicine in Houston, the Fred Hutchinson Cancer Research Center in Seattle, and the Ohio State University MS Center in Columbus.
The aim of the study was to determine the five-year durability of disease stabilization in patients with MS after high-dose therapy and autologous transplantation. An interim analysis at three years was published in JAMA Neurology.
The primary end point was event-free survival after transplant in the five-year period of follow-up. The end point included relapse, defined as neurologic signs or symptoms lasting more than 48 hours; MRI abnormalities at more than 12 months after transplant; progression in disability after six months post-transplant (as measured by Expanded Disability Status Scale or EDSS); and mortality. The end point was similar to no evidence of disease activity (NEDA), said Dr. Nash.
Patients who were eligible for the study were age 18 to 60, met McDonald criteria, and had had MS for less than 15 years. Patients had relapsing-remitting MS with cumulative disability or progressive-relapsing MS. EDSS score had to be between 3.0 and 5.5. Patients had to have T2 abnormalities consistent with MS and two or more relapses within 18 months on therapy, with an EDSS increase of more than 0.5. “I don’t think we had anyone in the study that met the second criterion, which was relapse on therapy with an EDSS increase of more than 1.0 and one separate event with gadolinium-enhancing lesions on MRI,” Dr. Nash said. A panel of two neurologists and one transplant physician reviewed the patients.
There were 25 patients in the HALT-MS trial. Median age at mobilization was 37 (range, 26 to 52). The study cohort was mostly female (17 female, 8 male). Baseline EDSS score was 4.5 (range, 3.0 to 5.5). Median disease duration was 4.9 years (range, seven months to 12 years). Therapies that patients had failed prior to study entry included interferon beta-1a (22 patients), interferon beta-1b (one patient), glatiramer acetate (18 patients), mitoxantrone (eight patients), natalizumab (six patients), and other therapies (11 patients).
James D. Bowen, MD, of the Swedish Neuroscience Institute in Seattle and a HALT-MS investigator, described the study intervention. “The protocol starts with mobilization of stem cells. Patients receive prednisone during this time so that the CSF is not vulnerable to MS attack. They then undergo leukapheresis to collect stem cells, which are further concentrated with a CD34 selection procedure that allows us to purify them.” Most patients with cancer require four or five pheresis sessions, Dr. Bowen noted, but patients with MS generally have healthy bone marrow, so most of the participants in HALT-MS only required two sessions. A few required three pheresis sessions.
“For our transplant protocol, we used BEAM plus ATG, which is a five-drug cocktail—BCNU, etoposide, Ara C, melphalan, and rabbit antithymocyte globulin,” said Dr. Bowen. “Immediately following that, transplant of the stem cells was done. After that, they got granulocyte-colony stimulating factor (G-CSF) to rev up the bone marrow, and we cover that with prednisone at days seven to 21 to avoid MS attacks precipitated by graft syndrome.”
Twenty-four patients went on to transplant. One of the patients had a pulmonary embolus and was not deemed a good candidate for transplantation. The rate of event-free survival, the primary end point, was 69.2%. Seven patients met the primary end point: two by progression of their disease, three by relapse of their disease, and two patients met end points much later in the follow-up, by changes in their MRI at 3.5 to 4.0 years.
The rate of five-year relapse-free survival was 86.9%. Two patients had changes on MRI. The two patients met primary end points and had their disease activity about 3.5 years after transplant. “There was an early event as well, at one year, but the patient who had MRI changes at one year had already met a primary end point by relapsing at about six months,” Dr. Nash said. The rate of disease progression-free survival was 91%.