Failure of cidofovir to reduce CMV-antigenemia in a child transplanted from a matched unrelated donor

Cytomegalovirus Treatment in Solid Organ Transplantation: An Update on Current Approaches

OBJECTIVE

The article reviews the safety and efficacy of treatments for cytomegalovirus (CMV) in solid organ transplantation.

DATA SOURCES

A literature review was conducted in PubMed, MEDLINE, and Clinicaltrials.gov from database inception through January 2024, using terms CMV, therapy, and solid organ transplantation.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials, meta-analyses, cohort studies, case reports, and guidelines were included. Letters to the editor, reviews, and commentaries were excluded.

DATA SYNTHESIS

After abstract screening and full-text review of 728 citations for eligibility, 53 were included. Valganciclovir and intravenous ganciclovir are drugs of choice for CMV management and, until recently, the availability of alternative options has been restricted due to toxicity. For instance, foscarnet and cidofovir serve as second-line agents due to potential bone marrow and renal toxicity. In patients with refractory or resistant CMV, maribavir, a novel oral agent, has proven efficacy and a lower adverse effect profile. However, in refractory or resistant CMV, foscarnet and cidofovir are preferred in invasive disease (CMV gastritis, CMV retinitis, and CMV encephalitis), high viral loads, and inability to tolerate oral preparations.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Consensus guidelines have not been revised since approval of novel antivirals in solid organ transplantation. Valganciclovir and ganciclovir remain drugs of choice for initial CMV therapy. Foscarnet, cidofovir, and maribavir are treatments for refractory or resistant-CMV.

CONCLUSIONS

Selection of CMV antiviral treatment should be determined by patient-specific factors, including severity of illness, resistant or refractory disease, dose-limiting adverse effects, and the preferred route of administration.

Cidofovir for Viral Infections in Immunocompromised Children: Guidance on Dosing, Safety, Efficacy, and a Review of the Literature

OBJECTIVE

To describe the use of cidofovir (CDV) for viral infections in immunocompromised children (IC) and provide guidance on dosing and supportive care.

DATA SOURCES

A PubMed search was conducted for literature published between 1997 and January 2022 using the following terms: cidofovir, plus children or pediatrics.

STUDY SELECTION AND DATA EXTRACTION

Limits were set to include human subjects less than 24 years of age receiving intravenous (IV) or intrabladder CDV for treatment of infections due to adenovirus, polyomavirus-BK (BKV), herpesviruses, or cytomegalovirus.

DATA SYNTHESIS

Data were heterogeneous, with largely uncontrolled studies. Conventional dosing (CDV 5 mg/kg/dose weekly) was commonly used in 60% (31/52) of studies and modified dosing (CDV 1 mg/kg/dose 3 times/week) was used in 17% (9/52) of studies, despite being off-label. Nephrotoxicity reported across studies totaled 16% (65/403 patients), which was higher for conventional dosing 29 of 196 patients (15%) than modified dosing 1 of 27 patients (4%). Saline hyperhydration and concomitant probenecid remain the cornerstones of supportive care, while some regimens omitting probenecid are emerging to target BKV.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

To our knowledge, this is the first comprehensive review of CDV use (indications, dosing, supportive care, response, and nephrotoxicity) in pediatric IC.

CONCLUSIONS

Effective utilization of CDV in IC remains challenging. Further prospective studies are needed to determine the optimal CDV dosing; however, less aggressive dosing regimens such as modified thrice weekly dosing or low dosing once weekly omitting probenecid to enhance urinary penetration may be reasonable alternatives to conventional dosing in some IC.

Cidofovir as primary pre-emptive therapy for post-transplant cytomegalovirus infections

Pre-emptive antiviral therapy for CMV infection following allogeneic stem cell transplantation is an effective strategy for preventing CMV disease. This entails the logistic difficulty of daily intravenous therapy with ganciclovir or foscarnet to clinically asymptomatic patients. Cidofovir (CDV) is effective against CMV in vitro and has the practical advantage of weekly administration. However, there are limited data on the pre-emptive use of CDV in CMV infections. We carried out a pilot study exploring the efficacy and toxicity of CDV as primary pre-emptive therapy for CMV infections monitored by PCR-based assays. CDV was used at 5 mg/kg with probenecid and hydration, weekly for a maximum of 4 weeks, followed by fortnightly maintenance treatment. Four patients were treated with CDV and two of them responded. Both the non-responders developed CMV disease. There was no renal toxicity noted in any of the patients, but three patients had severe vomiting and one developed uveitis, which precluded maintenance treatment in the two responders. Following failure of CDV, foscarnet was effective in controlling the CMV infection in both patients, although the infection recurred in both. Thus, larger randomised studies are required before CDV can be recommended as a primary pre-emptive therapy for post-transplant CMV infections.