Clinical trial demonstrates adoptive T-cell therapy may be successful in treating progressive multifocal leukoencephalopathy.
In a phase 2 clinical trial, an adoptive T-cell therapy showed promise in treating progressive multifocal leukoencephalopathy (PML), a rare brain infection that is often fatal to patients with cancer and autoimmune diseases.
The study, which was published in the New England Journal of Medicine, involved 3 patients with PML who were infused with donor T cells, targeting the BK virus, an infection that is genetically similar to the JC virus, which causes PML.
PML attacks the myelin sheath in the brain and can be deadly in patients with blood cancers, such as leukemia and lymphoma, and in individuals with AIDS and autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. There is currently no effective treatment for the infection, according to the study.
“The JC and BK viruses are genetically similar and share proteins that can be targeted by the immune system,” lead study author Katy Rezvani, MD, PhD, professor of the Department of Stem Cell Transplantation and Cellular Therapy at the University of Texas MD Anderson Cancer Center, said in a statement. “Because of these similarities, we hypothesized that T cells developed against BK virus may also be effective against JC virus infection.”
For the study, the researchers used BK virus-specific T cells from healthy donors in a bank of viral-specific T cells. The trial included 3 patients with third-party, partially human leukocyte antigen-matched (HLA) BK virus-specific T cells.
Patients infused with BK-specific T cells included:
· Patient with acute myeloid leukemia (AML) who previously received cord blood transplantation.
· Patient with JAK2-positive polycythemia rubra vera, a blood disorder that causes over-production of red blood cells, who had been treated with the targeted therapy agent ruxolitinib.
· Patient with AIDS who had discontinued highly active antiretroviral therapy due to adverse effects and was no longer able to walk.
According to the study, all 3 patients demonstrated a reduction in JC viral load in their cerebrospinal fluid (CSF) following the first infusion of the therapy. Viral loads decreased from 700 to 78 copies in the first patient, 230,000 to 5200 copies in the second, and 4300 to 1200 in the third patient.
Two additional infusions successfully cleared the virus in the CSF in the first patient and there were no signs of PML 26 months after the first infusion. The second patient had a reduced JC viral load after the second infusion, but no further improvement was observed, and the patient died 8 months following the first infusion. After additional infusions, the third patient was completely cleared of the JC virus and fully regained mobility 9 months after the first infusion.
“We are encouraged that off-the-shelf, third-party partially HLA-matched BK viral-specific T cells may provide a therapy for PML,” Dr Rezvani said. “Further study in a larger group of patients is required to determine the success rate, durability, and long-term adverse events with this treatment.”
Although more research is needed, the researchers concluded that the findings have potential therapeutic implications for leukemia, lymphoma, and other immunodeficiency disorders.
Muftuoglu M, Olson A, Marin D, et al. Allogeneic BK virus-specific T cells for progressive multifocal leukoencephalopathy. NEJM. 2018. Doi: 10.1056/NEJMoa1801540
Cancer patients with rare deadly brain infection treated successfully with off-the-shelf adoptive T-cell therapy in clinical trial [news release]. MD Anderson’s website. https://www.mdanderson.org/newsroom/2018/10/cancer-patients-with-rare-deadly-brain-infection-treated-successfully-with-off-the-shelf-adoptive-t-cell-therapy-in-clinical-trial.html. Accessed October 10, 2018.