A randomized pilot trial comparing anti-thymocyte globulin with anti-thymocyte globulin plus post transplant cyclophosphamide for prophylaxis against acute and chronic graft versus host disease in matched donor hematopoietic cell transplants - a study from the Cell Therapy Transplant Canada/ Australasian Leukemia Lymphoma Group Consortium.
Irwin Walker, Uday Deotare, Mohamed Elemary et al.
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In 30 seconds
This multicentre randomized pilot trial compared anti-thymocyte globulin (ATG) alone with ATG plus post-transplant cyclophosphamide (PTCy) for graft-versus-host disease prophylaxis in 79 patients with AML or MDS receiving 8/8 HLA-matched donor hematopoietic cell transplants. The primary safety endpoint, 100-day overall survival, was similar: 95.0% (37 of 39 patients) with ATG and 94.9% (38 of 40 patients) with ATG plus PTCy (p > 0.9). Serious adverse events and longer-term survival, relapse, and non-relapse mortality were also similar. Neutrophil engraftment was slower with the combination.
Key findings
- 100-day overall survival was 95.0% (37 of 39 patients) with ATG versus 94.9% (38 of 40 patients) with ATG plus PTCy (p > 0.9).
- Serious adverse events occurred in 26 (65.0%) versus 25 (64.1%) patients in the ATG and combination arms.
- Median time to neutrophil engraftment was 19 (10-45) versus 22 (15-56) days with ATG versus ATG plus PTCy (p = 0.007).
- At 12 months, overall survival was 72.5% versus 75.8%; six-month relapse incidence was 15.0% versus 15.7%, and non-relapse mortality was 7.5% versus 8.0%.
Why it matters
The trial provides randomized pilot safety data for adding PTCy to ATG in matched-donor transplantation, a combination the investigators consider suitable for phase III evaluation. Similar early survival and serious adverse-event rates are reassuring, while the longer time to neutrophil engraftment with the combination is a relevant outcome to assess in larger studies.
What to keep in mind
This was a pilot trial with 79 patients, and the abstract reports safety and survival outcomes rather than comparative efficacy for preventing acute or chronic graft-versus-host disease.