However, the results of the new study suggest that one-time high-dose immunosuppressive therapy (HDIT), followed by autologous hematopoietic cell transplantation (HCT), may lead to long-term remission for patients with RRMS.
The goal of HDIT/HCT is to remove all MS-causing cells from the body.
The therapy involves collecting a patient's blood-forming stem cells, before treating them with high-dose chemotherapy to destroy their immune system. The blood-forming stem cells are then returned to the patient, effectively "resetting" their immune system.
In 2014, Dr. Nash and colleagues reported the 3-year results of their phase II clinical trial for HDIT/HCT. The trial involved 24 patients with RRMS aged between 26 and 52. All patients were using currently available medications for their condition, but none were experiencing a reduction in relapses or disease progression.
For the trial - funded by the National Institute of Allergy and Infectious Diseases (NIAID) - each patient received HDIT/HCT. The team found that almost 80 percent of patients experienced no relapses, worsening of disability, or new brain lesions in the 3 years following treatment.
In the new study, the researchers assessed the same group of patients 5 years after HDIT/HCT. They found that 69 percent of patients had still not experienced relapses, disability progression, or new brain lesions since the treatment.
Importantly, none of the patients had used any RRMS medications since treatment with HDIT/HCT.
Reported side effects of HDIT/HCT included cytopenias (a reduction in blood cells) and infections. Three patients died during the 5-year follow-up, but the researchers say that their deaths were not related to their treatment.