Allogeneic stem cell transplantation (ASCT) is the only current treatment with the potential to cure myelofibrosis (MF), but is also carries a high risk of life-threatening side effects for most MF patients. ASCT involves transferring stem cells from a healthy person (the donor) to the patient. The procedure follows high-intensity chemotherapy, potent drugs that must be toxic enough to kill leukemic cells, or radiation therapy.
Most patients with MF are older and often have other health conditions that may impair organ function. Older individuals are also more likely to have other medical problems, develop complications from the treatment and have decreased tolerance for the cumulative effects of the intensive chemotherapy and for radiation treatments needed before the transplant. However, these are generalizations. ASCT can be used in older people when medically appropriate. Whether or not a patient is a candidate for transplantation is determined by medical indications and the availability of a donor. There is no specific age cut-off for stem cell transplantation.
Reduced-intensity or "nonmyeloblative" allogeneic stem cell transplantation is a type of transplant that uses lower doses of chemotherapy or radiation, and it is being used to treat some patients with leukemia, lymphoma or myeloma. Compared to a standard ASCT, a reduced-intensity transplant delivers lower doses of chemotherapy drugs and/or radiation to the patient in preparation for the transplant. The success of reduced-intensity transplantation is a result of the graft-versus-tumor effect of the donor stem cells, rather than of high doses of chemotherapy. This approach may benefit older and sicker patients and other selected patients. Reduced-intensity transplants are now done with results that are increasingly encouraging for MF patients.
The numbers of studies and study patients are too small to determine the exact role stem cell transplantation should play in treating MF. Clinical trials are under way to study the safety and effectiveness of modified stem cell transplantation.