According to the findings of a phase 2 trial, the use of reduced-intensity conditioning HLA-haploidentical bone marrow transplant (BMT) and posttransplantation cyclophosphamide (PTCy)-based graft vs host disease (GVHD) prophylaxis for severe aplastic anaemia (SAA) among patients without a fully matched donor resulted in high rates of survival and low rates of acute and chronic GVHD.
The findings were reported in the journal Blood.
The trial’s cohort included 35% of patients from underrepresented racial and/or ethnic groups, suggesting that this BMT method for patients without a fully matched donor not only improves outcomes but also broadens access to BMT.
The single-arm, phase 2 trial treated 27 patients with SAA who lacked a fully matched donor with reduced-intensity conditioning, HLA-haploidentical BMT, and PTCy-based GVHD prevention. During conditioning, the first 7 patients received a total body irradiation dose of 200 cGy, but the subsequent 20 patients received a dose of 400 cGy.
The trial’s key endpoints were feasibility and safety. One-year OS, rates of grade 2 and 4 acute or chronic GVHD, and graft failure were secondary objectives.
The overall cohort’s median age was 25, with 48% of patients being female. There were 63% non-Hispanic White patients, 19% non-Hispanic Black patients, 3% Hispanic Black patients, 11% Asian/Pacific Islander patients, and 3% who reported more than one race. A very severe diagnosis was seen in 52% of patients, and clonality was present in 81% at baseline.
The cumulative rate of grade 2 or 4 acute GVHD at day 100 was 7%. The rate of persistent GVHD was 4% after 2 years.
Infections were prevalent, affecting 67% of patients, however the majority were of the grade 2 variety. Two people died as a result of an infection. The most common cause was viral, followed by bacterial and fungal infections. The prevalence of CMV infection was 40.7%, with 54.5% of those infected requiring treatment.
Neutrophil recovery was accomplished in 26 participants by day 28, with a median duration to recovery of 17 days. The 100-day platelet recovery incidence was 88%, with a median duration to platelet recovery of 25.5 days.
At one year, the whole cohort’s OS was 92%, which was maintained through year three. The OS rate was 100% among the 20 patients who got the greater dosage of irradiation. The lower irradiation dose was also linked to an increased probability of graft failure, which occurred in three patients compared to none in the higher dose cohort (P =.01).
“Not only does this approach avoid any adverse ramifications of immunosuppressive therapy and its low failure-free survival, but the use of haploidentical donors also expands access to BMT across all populations,” the authors concluded in their paper.
Source: Hematology Advisor