Rissling O, et al. - Researchers retrospectively studied valganciclovir dosing patterns in renal transplant patients receiving cytomegalovirus (CMV) prophylaxis. They found that most patients did not receive the recommended valganciclovir dose. In a large proportion of patients, effective prophylaxis was maintained despite obvious underdosing and it was not found to be associated as a risk factor for CMV viraemia or leucopenia.

Methods

• Between August 2003 and August 2011, a retrospective investigation of valganciclovir dosing in renal transplant patients receiving CMV prophylaxis was carried out.
• Researchers analysed valganciclovir dosing, CG-CrCl, CMV viraemia (CMV-PCR <750 copies/mL), leucopenia (<3500/µL) and neutropenia (<1500/µL) in the first year post-transplant.
• On days 30 and 60 post-transplant, they analyzed dosing pattern in relation to estimated creatinine clearance regarding CMV viraemia, leucopenia and neutropenia.

Results

• Data showed that valganciclovir prophylaxis, lasting for 129 ± 68 days with a mean dose of 248 ± 152 mg/day, was received by 635 patients, of whom 112/635 (17.7%) developed CMV viraemia, 166/635 (26.1%) leucopenia and 48/635 (7.6%) neutropenia.
• Within 1 year post-transplant, CMV resistance was detected in 3 patients.
• Researchers found that only 137/609 (22.6%) patients received the recommended dose, while n = 426 (70.3%) were underdosed and n = 43 (7.1%) were overdosed at Day 30 post-tx.
• Donor positive D (+)/receptor negative R (-) status and short prophylaxis duration, but not low valganciclovir dose, were identified as risk factors for CMV viraemia.
• In addition, D+/R- status and low renal function were reported as risk factors for developing leucopenia.
• Researchers observed no significant differences in dosing frequency in patients developing neutropenia or not (P=0.584).