Optimizing cyclosporine A dose post allogeneic hematopoietic stem cell transplantation in paediatric cancer patients

Background/Objectives Cyclosporine A (CSA) dosing has been complicated by considerable intra-patient and inter-patient variability in pharmacokinetics, which is affected by different factors. We aimed to assess the various factors that might affect the CSA dose and its plasma level. Patients and methods This retrospective study included paediatric cancer patients who underwent allogeneic hematopoietic stem cell transplant at the Children's Cancer Hospital Egypt 57357 from matched related donors with CSA as graft versus host disease prophylaxis. The CSA initial dose was 1.5 mg/kg IV Q12H. Then, it was titrated according to the level and drug toxicity. Cyclosporine A trough levels were assessed two to three times per week using the Emit 2000 cyclosporine-specific assay. Moreover, factors that may affect cyclosporine levels, such as age, sex, weight and the antifungal used, were analyzed to determine their effect on CSA plasma levels. Results There were 119 patients included in the study. The median age was 10 years; and 43% of them used voriconazole as a prophylactic antifungal. The multivariate analysis revealed that female patients, those >9 years or on voriconazole reached the target level at low initial CSA doses. A higher probability (93%) of reaching the desired plasma level with doses 1.5 mg/kg IV Q12H was observed among patients >9 years, and on voriconazole. While those who were ≤9 years and not on voriconazole required doses >1.5 mg/kg IV Q12H, with an 89% probability of reaching the desired level. Conclusion This study suggests that the initial CSA dose should consider the patient's age and the antifungal used. Patients >9 years and/or on voriconazole may require lower initial CSA doses and could start with 1.5 mg/kg IV Q12H.