Alternative antiepileptic medications (AEMs) appear to be safe for seizure prevention after busulfan and cyclophosphamide conditioning for allogeneic hematopoietic cell transplantation (HCT), according to a recent study published in Biology of Blood and Marrow Transplantation.

The retrospective study used registry data from the Center for International Blood and Marrow Transplant Research (CIBMTR®) to assess whether alternative AEM treatment was associated with a higher risk of relapse compared with phenytoin in patients who had busulfan and cyclophosphamide conditioning regimens before first, human leukocyte antigen (HLA)-matched allogeneic HCT between 2004 and 2014. Secondary endpoints included renal failure requiring dialysis and idiopathic pneumonia syndrome.

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The final patient cohort included 2155 patients; 1460 received phenytoin and 695 received alternative AEMs. Median age was 46 years for the phenytoin group and 47 years for the alternative AEM group.

Median follow-up after allogeneic HCT was 73 months in the phenytoin group and 61 months in the alternative AEM group. No differences were observed for relapse risk, disease-free survival, overall survival, nonrelapse mortality, or acute or chronic graft-versus-host disease between the 2 AEM groups.

In a subset of patients, risk for dialysis was lower in the alternative AEM group compared with the phenytoin group when receiving intravenous busulfan (hazard ratio [HR], 0.52; 95% CI, 0.34-0.79; P =.003). Dialysis was required in 4% of patients (29/608) in this subset receiving alternative AEMs compared with 7% of patients (70/1073) in this subset receiving phenytoin.

In pediatric patients receiving intravenous busulfan, risk for relapse (adjusted HR, 1.61; 95% CI, 1.00-2.61; P =.05) and risk for interstitial pneumonia syndrome (adjusted HR, 3.10; 95% CI, 1.26-7.64; P =.01) were higher in the alternative AEM group compared with the phenytoin group.

Although alternative AEMs appear to be safe for adults receiving busulfan and cyclophosphamide conditioning, special treatment considerations should be given for children in this context.

Reference

1.     McCune JS, Wang T, Bo-Subait K, et al. Association of antiepileptic medications with outcomes after allogeneic hematopoietic cell transplantation with busulfan/cyclophosphamide conditioning [published online March 11, 2019]. Biol Blood Marrow Transplant. doi: 10.1016/j.bbmt.2019.03.001