|Durham, NC – A new study demonstrates how an infusion of stem cells can assist in treating severe cases of aplastic anemia (AA) that do not respond to immunosuppressive therapy (IST) alone. The study, which appears in STEM CELLS Translational Medicine (SCTM), offers hope for patients with this rare disease, which occurs when the bone marrow does not produce enough blood cells to meet the body’s needs.
People with AA suffer from fatigue, frequent infections, rapid heart rate and bleeding. The more severe cases can be life threatening. While IST is accepted as the first-line treatment option for AA, 30 to 40 percent of patients with severe cases don’t respond well to treatment and continue to suffer from an abnormally low level of red blood cells, white blood cells and platelets. IST therapy generally consists of anti-thymocyte globulin, which is an infusion of horse or rabbit-derived antibodies against human T cells, and the immunosuppressant medication cyclosporine.
These patients who don’t respond to IST might require an allogeneic hematopoietic stem cell transplant (HSCT). However, about a third of them aren’t able to find a suitable donor. Also, people aged 50 and older are not eligible for transplant. Another issue with HSCT is that complications such as graft versus host disease and graft failure may occur. As such, the five-year overall survival rate of patients with severe AA that is refractory to IST is less than 60 percent.
In the SCTM study, a team of researchers led by Yan Pang, M.D., and Yang Xiao, M.D., Ph.D., of the Department of Hematology, Guangzhou General Hospital of Guangzhou Military Command, in China, wanted to learn whether bone marrow-derived mesenchymal stromal cell (BM-MSC) transfusions might help patients who did not respond to IST. The phase two clinical trial involved 74 patients at seven centers who each received four doses of stem cells over a period of four weeks. Patients with response rates after the first month continued to receive infusions.
“After 12 months, our evaluations showed that the overall response rate was 28.4 percent, with 6.8 percent complete responses and 21.6 percent partial response,” Dr. Xiao reported. “At 17 months, the overall survival of the initial 74-patient group was 87.8 percent. Seven patients developed transitory and mild headache and fever, but no other adverse events were observed.”
“Our study strongly indicates that MSC infusion is a promising therapy for severe AA, but improved MSC cultures in vitro and the MSC doses need further study to maximize their therapeutic potential,” added Dr. Pang.
“This phase II clinical study, involving 74 patients, is significant because it suggests that a stem cell transfusion can be used to treat aplastic anemia that is non-responsive to first-line therapies. The advantages of the treatment are its safety and costs,” said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.
Click for the full article, “Allogeneic bone marrow-derived mesenchymal stromal cells expanded in vitro for treatment of aplastic anemia: a multicenter phase II trial.”