Busulfan- or Thiotepa-Based Conditioning in Myelofibrosis: A Phase II Multicenter Randomized Study from the GITMO...

Area of Science:

• Hematology
• Oncology
• Transplantation Medicine

Background:

• Myelofibrosis is a serious bone marrow disorder.
• Hematopoietic stem cell transplantation (HSCT) is a potential curative therapy.
• Conditioning regimens are crucial for HSCT success.

Purpose of the Study:

• To compare the efficacy of fludarabine-busulfan (FB) versus fludarabine-thiotepa (FT) as conditioning regimens for HSCT in myelofibrosis.
• To evaluate progression-free survival (PFS) as the primary endpoint.
• To assess overall survival (OS), relapse rates, nonrelapse mortality (NRM), and graft failure.

Main Methods:

• A randomized study involving 60 myelofibrosis patients.
• Patients received either FB or FT conditioning before HSCT.
• Donors included HLA-identical siblings, matched unrelated, and mismatched unrelated donors.
• Median follow-up was 22 months.

Main Results:

• Two-year PFS was 43% for FB vs. 55% for FT (P=.28).
• Two-year OS was 54% for FB vs. 70% for FT (P=.17).
• NRM was 21% in both arms (P=.99).
• Better PFS was observed in patients with intermediate-1 DIPSS score (P=.03).
• Previous splenectomy and splenomegaly impacted engraftment.

Conclusions:

• Fludarabine-busulfan and fludarabine-thiotepa conditioning regimens demonstrate comparable clinical outcomes after HSCT for myelofibrosis.
• The choice between FB and FT may not significantly alter key survival endpoints.
• Further research may explore patient stratification based on prognostic scores and pre-transplant factors like splenomegaly.