Pre-emptive treatment for cytomegalovirus viraemia to prevent cytomegalovirus disease in solid organ transplant recipients.

Background: Cytomegalovirus (CMV) is a significant cause of morbidity and death in solid organ transplant recipients. Pre-emptive treatment of patients with CMV viraemia using antiviral agents has been suggested as an alternative to routine prophylaxis to prevent CMV disease. This is an update of a Cochrane review first published in 2006 and updated in 2013.

Objectives: To determine the benefits and harms of pre-emptive treatment of CMV viraemia to prevent CMV disease and death (any cause) and the indirect effects of CMV infection (acute rejection, graft loss, opportunistic infections) in solid organ transplant recipients.

Search methods: The Cochrane Kidney and Transplant Register of Studies was searched up to 17 December 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

Selection criteria: We included randomised controlled trials (RCTs) and quasi-RCTs comparing pre-emptive treatment with placebo, no specific treatment, or antiviral prophylaxis in solid organ transplant recipients.

Data collection and analysis: Two authors independently assessed the eligibility of the identified studies, assessed the risk of bias, and extracted all data. Results were expressed as risk ratio (RR) and 95% confidence intervals (CI) for dichotomous outcomes. Statistical analyses were performed using a random-effects model. The certainty of evidence was assessed per outcome using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.

Main results: In this update, we have included seven new studies, bringing the total number of included studies to 22 (1883 participants). Of these, seven investigated pre-emptive treatment versus placebo or standard care, 12 looked at pre-emptive treatment versus antiviral prophylaxis, one study investigated oral versus intravenous pre-emptive treatment, one investigated pre-emptive valganciclovir versus pre-emptive ganciclovir, and one investigated letermovir 40 mg twice/day versus 80 mg once/day. Studies were conducted in Australia, Brazil, the Czech Republic, Germany, Italy, Japan, Norway, Spain, South Korea, and the USA. Organ transplant recipients included kidney, liver, heart, lung, and kidney-pancreas. Thirteen studies were single-centre studies, six were multicentre, and three were unknown. The number of participants ranged from 12 to 296. Overall, selection bias was unclear (55%); performance, detection and attrition bias were high (91%, 63% and 95%, respectively), and reporting bias was low (55%). Compared with placebo or standard care, pre-emptive treatment probably reduces the risk of CMV disease (7 studies, 315 participants: RR 0.29, 95% CI 0.11 to 0.80; I² = 54%; moderate-certainty evidence) but may result in little or no difference in death (any cause) (3 studies, 176 participants: RR 1.23, 95% CI 0.35 to 4.30; I² = 0%; low-certainty evidence). Pre-emptive treatment may result in little or no difference in CMV organ involvement, CMV-associated symptoms, acute rejection, graft loss, other infections or leucopenia. Compared to prophylaxis, pre-emptive treatment may make little or no difference to the risk of developing CMV disease (11 studies, 1322 participants: RR 0.97, 95% CI 0.47 to 2.01; I² = 54%; low-certainty evidence) and probably makes little or no difference to death (any cause) (9 studies, 1098 participants: RR 0.95, 95% CI 0.60 to 1.52; I² = 0%; moderate-certainty evidence). Pre-emptive treatment may increase the risk of CMV infection (8 studies, 867 participants: RR 1.97, 95% CI 1.48 to 2.61; I² = 66%; low-certainty evidence). The risk of leucopenia (7 studies, 869 participants: RR 0.57, 95% CI 0.38 to 0.87; I² = 33%; moderate-certainty evidence) and neutropenia (5 studies, 859 participants: RR 0.63, 95% CI 0.44 to 0.90; I² = 0% moderate certainty evidence) probably decreases with pre-emptive therapy. There may be little or no difference in the risks of acute rejection, graft loss, and infections other than CMV. Single studies were identified for comparisons between different pre-emptive treatments: 1) oral ganciclovir versus IV ganciclovir; 2) valganciclovir versus ganciclovir; 3) 40 mg twice/day versus 80 mg once/day. No differences between these treatment modalities in terms of CMV disease, death (any cause), or adverse events were identified.

Authors' conclusions: In this review, we have included seven new studies, yet the available evidence is overall of low certainty and the conclusions remain similar to the previous version of this review. Pre-emptive treatment probably reduces the risk of CMV disease compared with placebo or standard care. There were no clear differences between pre-emptive treatment and prophylaxis to prevent CMV disease or reduce the risk of death (any cause). The risk of CMV infection may be higher for patients receiving pre-emptive therapy, but the risk of adverse events, such as leucopenia, is probably lower.