From the Journals

NMA haploidentical allo-BMT plus post-transplant cyclophosphamide deemed safe, effective for CLL



Nonmyeloablative haploidentical allo-bone marrow transplantation with posttransplantation cyclophosphamide is a safe and effective treatment option for patients with chronic lymphocytic leukemia (CLL), according to a study published in Biology of Blood and Marrow Transplantation.

The number of patients undergoing haploidentical allo-BMT has increased substantially, with the advent of new graft-versus-host disease (GVHD) prophylaxis strategies, such as posttransplantation cyclophosphamide (PTCy), that reduce the risk of GVHD complications; however there have been few studies assessing the results of this treatment regimen, according to the authors.

The study assessed 64 consecutive patients with CLL between Jan. 2005 and Aug. 2018 who underwent haploidentical allo-BMT. The median age was 59 years; 4 patients (6.2%) underwent allo-BMT after first-line treatment; 20 patients (31.2%) underwent allo-BMT after second-line treatment, and 40 patients (62.5%) underwent allo-BMT after three or more lines of treatment for relapsed and/or refractory disease.

All patients received a nonmyeloablative (NMA) conditioning regimen consisting of fludarabine, cyclophosphamide, and 200 cGy total body irradiation. Patients received PTCy (i.v. 50 mg/kg per day) on days +3 and +4, along with additional GVHD prophylaxis with mycophenolate mofetil between days +5 and +35 and tacrolimus or sirolimus between days +5 and +180.

For all 64 patients, the median duration of follow-up was 4.4 years based on the reverse Kaplan-Meier method. The 4-year overall survival (OS) was 52%, and the 4-year progression-free survival (PFS) was 37%. The 56 patients with less than 20% marrow CLL involvement before undergoing allo-BMT had a 4-year OS of 61%, a 4-year PFS of 43%, and a median OS of 4.8 years, according to the authors.

Regression analysis demonstrated that donor age, stem cell source, IGHV mutation status, or grade II-III acute GVHD did not affect risk of progression or survival.

“The majority of our patients had unfavorable risk factors, and collectively our data show that haploidentical allo-BMT with PTCy in CLL with less than 20% marrow involvement is a safe treatment option carrying a low risk of serious GVHD and other toxicities,” the researchers concluded.

The study was supported by National Institutes of Health, National Cancer Institute grants. The authors reported that they had no disclosures.

SOURCE: Suman P et al. Biol Blood Marrow Transplant. 2020 Mar 1;26:502-8. doi: 10.1016/j.bbmt.2019.11.008

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