Introduction: To evaluate the impact of two viral load (VL) thresholds for terminating antiviral treatment on the cytomegalovirus (CMV) recurrence in kidney transplant recipients (KTRs) following a preemptive strategy.
Methods: A before-and-after quasi-experimental study was conducted on 1,048 CMV IgG-positive KTRs (Mar/2018- Jul/2020). CMV viremia was monitored weekly for three months post-transplant, with antiviral treatment initiated upon asymptomatic viremia exceeding 5,000 IU/mL or symptomatic CMV. In both eras (before and after), the CMV VL was monitored to guide the duration of therapy, aiming to achieve a completely undetectable VL (era before, Mar/2018-Jul/2019, n= 664) or once the VL was 200 IU/mL (era after, Aug/2019-Jul/2020, n= 384). The primary outcome was CMV recurrence.
Results: All patients received a single 3.0 mg/kg dose of rATG for induction and were maintained on a regimen of tacrolimus (99.5%), prednisone (100%), and mycophenolate (100%). In the entire cohort, 515 patients (49.1%) required preemptive CMV treatment; of these, 320 (30.5%) were asymptomatic, and 195 (18.6%) met the criteria for CMV disease. The median treatment duration was 27 days (21-33), with an 11.4% overall incidence of CMV recurrence. When comparing the two eras, no differences were observed in recipient characteristics, but in the era after, donors were older (54 vs. 52 years old, p=0.003) with a higher frequency of deceased donors (94.3% vs. 90.2%, p=0.02). The frequency of patients requiring a first CMV treatment (50.5% before vs. 46.9% after, p=0.26) and the incidence of CMV disease (20.3% vs. 15.3%, p=0.33) was similar in both eras. The time to achieve the CMV treatment goal decreased significantly post-protocol change from 27 (22-35) days in the era before to 23 (19-29) after (p<0.001), with no impact on the incidence of CMV recurrence: 10.8% before vs. 12.2% after, p=0.24 (HR= 1.29, 95%CI=0.89-1.87, p=0.17).
Conclusions: Adjusting preemptive strategy thresholds to allow a low but detectable VL at the cessation of antiviral therapy significantly shortened treatment duration without increasing CMV recurrence risk, thereby offering a potentially optimized approach for managing CMV in KTRs.