Mycophenolate mofetil plus tacrolimus as acute GvHD prophylaxis in pediatric patients

The use of mycophenolate mofetil (MMF) in children undergoing allogeneic stem cell transplantation requires further investigation. In Pediatric Blood & Cancer, Olga Militano from the Department of Pediatrics, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, USA, and colleagues reported results of a study investigating the efficacy of dosing MMF every eight hours in combination with tacrolimus as acute graft-versus-host disease (aGvHD) prophylaxis in pediatric, adolescent and young adult patients undergoing allogeneic stem cell transplant.

All patients (n = 35, median age = 12.54 years [range, 0.11–23.45]) in this study received MMF (900 mg/m2/dose or 15 mg/kg/dose IV/OS q8h) and tacrolimus (0.03–0.04 mg/kg/day IV continuous infusion or 0.12–0.16 mg/kg/day OS divided q8–12h) starting on Day 1. Conditioning regimens were given as follows: MA conditioning (n = 18, 51%), NMA conditioning (n = 8, 23%), and RIC (n = 9, 26%). Median time to myeloid and platelet engraftment was 15 days (range, 10–44) and 30 days (range 18–270), respectively.

Key findings:

GvHD

• Probability of grade II–IV aGvHD: 22.8% (95% CI, 5.2–47.9)
• Probability of grade III–IV aGvHD: 5.7% (95% CI, 0–48.9)
• Probability of limited cGvHD: 12.2% (95% CI, 0.3–45.7)
• Probability of extensive cGvHD: 22.6% (95% CI, 3.4–52.2)
• MA conditioning significantly associated with a higher risk of developing grade II–IV aGvHD than NMA or RIC regimens: HR = 6.6 (95% CI, 0.91–48), P = 0.01

Survival

• 1-year overall survival: 82% (95% CI, 64.1–99.8)
• Causes of death: aGvHD(n=1), cGvHD (n=2), viral infection (n = 1), recurrent/persistent disease (n = 2), and thrombotic microangiopathy (n = 1)

Results of this study showed that dosing of MMF every eight hours at a dose of 900 mg/m2 in combination with tacrolimus is safe and efficient. Encouraging results were observed in terms of the probability of grade II–IV aGvHD. The study group recommended larger studies further evaluating the PK and optimal dosing of MMF in the late post-transplant period.