Study of Fludarabine Based Conditioning for Allogeneic Stem Cell Transplantation for Myelofibrosis

Overview

Stem cell transplantation is used to treat may types of diseases. There a 2 types of transplants, conventional (very intense) and reduced intensity-non-myeloablative, also called mini-transplants. This study proposes to use a conditioning regimen for allogeneic transplantation along with a reduced intensity transplant. Conditioning regiment is the name for the combination of chemotherapy drugs that is given to patients before receiving a transplantation of donor stem cells. It is hoped that the regimen designed for this study proves to be less toxic and has an equal or better anticancer effect than the regimens that are normally used. The regimen being used is a combination of two chemotherapy drugs, fludarabine and melphalan. This regimen has been studied in recipients of matched sibling transplants and in recipients of alternative donor stem cells in other hematologic malignancies. Those subjects, who receive stem cells from an unrelated donor, will also receive and additional drug called ATG or anti thymocyte globulin. ATG suppresses the immune system, thus reducing the chances for the recipient rejecting the transplant (graft). The purpose of this study is to observe if reduced intensity transplants can be used to allow engraftment or "take" of the donor's bone marrow. Studies conducted in the past show this type of transplant is much less toxic than traditional bone marrow transplants. Reduced intensity transplants may be better tolerated by patients who may experience serious side effects from standard (very intense) stem cell transplant. The study has been recently amended to follow all subjects for survival.

This study is designed as a single arm Phase II clinical trial in patients with myelofibrosis who are eligible for transplantation from a related donor or from an unrelated donor source. Patients will be accrued into two separate strata defined by donor type. Each of the two strata will be analyzed separately. Patients will be followed yearly from time of enrollment into the study to assess clinical response and overall, progression and event free survival, as well as incidence and degree of acute and chronic GVHD. We will estimate cumulative survival and transplant related mortality in patients enrolled in each of the two strata.