Model of population pharmacokinetics of cidofovir in immunocompromised children with cytomegalovirus and adenovirus infection

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.

A quick algorithmic review on management of viral infectious diseases in pediatric solid organ transplant recipients

Pediatric solid organ transplant is a life-saving procedure for children with end-stage organ failure. Viral infections are a common complication following pediatric solid organ transplantation (SOT), which can lead to increased morbidity and mortality. Pediatric solid organ transplant recipients are at an increased risk of viral infections due to their immunosuppressed state. The most commonly encountered viruses include cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), varicella-zoster virus (VZV), adenoviruses, and BK polyomavirus. Prevention strategies include vaccination prior to transplantation, post-transplant prophylaxis with antiviral agents, and preemptive therapy. Treatment options vary depending on the virus and may include antiviral therapy and sometimes immunosuppression modification. This review provides a Quick Algorithmic overview of prevention and treatment strategies for viral infectious diseases in pediatric solid organ transplant recipient.

Adenovirus Infection in Hematopoietic and Solid Organ Paediatric Transplant Recipients: Treatment, Outcomes, and Use of Cidofovir

BACKGROUND

human adenovirus (hAdV) infection constitutes an important cause of morbidity and mortality in transplant recipients, due to their immune status. Among drugs currently available, cidofovir (CDF) is the most prescribed.

METHODS

Retrospective study of hAdV infection in paediatric transplant recipients from a tertiary paediatric centre, describing characteristics, management, and outcomes, and focused on the role of CDF.

RESULTS

49 episodes of infection by hAdV were detected during a four-year period: 38 episodes in patients that received allogeneic hematopoietic stem cell transplantation (77.6%) and 11 in solid organ transplant recipients (22.4%). Twenty-five patients (52.1%) were symptomatic, presenting mainly fever and/or diarrhoea. CDF was prescribed in 24 patients (49%), with modest results. CDF use was associated with the presence of symptoms resulting in lower lymphocyte count, paediatric intensive care unit admission, and high viral load. Other therapeutic measures included administration of intravenous immunoglobulin, reducing immunosuppression, and T-lymphocyte infusion. Despite treatment, 22.9% of patients did not resolve the infection and there were three deaths related to hAdV infection. All-cause mortality was 16.7% (8 episodes) by 30 days, and 32.7% (16 episodes) by 90 days, of which, 3 episodes (3/16, 18.8%) were attributed to hAdV directly.

CONCLUSIONS

hAdV infection had high morbidity and mortality in our series. CDF use is controversial, and available therapeutic options are limited. Transplant patients with low lymphocyte count are at higher risk of persistent positive viremias, and short-term survival of these patients was influenced by the resolution of hAdV infection.

Phosphonates and Phosphonate Prodrugs in Medicinal Chemistry: Past Successes and Future Prospects

Compounds with a phosphonate group, i.e., -P(O)(OH)₂ group attached directly to the molecule via a P-C bond serve as suitable non-hydrolyzable phosphate mimics in various biomedical applications. In principle, they often inhibit enzymes utilizing various phosphates as substrates. In this review we focus mainly on biologically active phosphonates that originated from our institute (Institute of Organic Chemistry and Biochemistry in Prague); i.e., acyclic nucleoside phosphonates (ANPs, e.g., adefovir, tenofovir, and cidofovir) and derivatives of non-nucleoside phosphonates such as 2-(phosphonomethyl) pentanedioic acid (2-PMPA). Principal strategies of their syntheses and modifications to prodrugs is reported. Besides clinically used ANP antivirals, a special attention is paid to new biologically active molecules with respect to emerging infections and arising resistance of many pathogens against standard treatments. These new structures include 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidines or so-called "open-ring" derivatives, acyclic nucleoside phosphonates with 5-azacytosine as a base moiety, side-chain fluorinated ANPs, aza/deazapurine ANPs. When transformed into an appropriate prodrug by derivatizing their charged functionalities, all these compounds show promising potential to become drug candidates for the treatment of viral infections. ANP prodrugs with suitable pharmacokinetics include amino acid phosphoramidates, pivaloyloxymethyl (POM) and isopropoxycarbonyloxymethyl (POC) esters, alkyl and alkoxyalkyl esters, salicylic esters, (methyl-2-oxo-1,3-dioxol-4-yl) methyl (ODOL) esters and peptidomimetic prodrugs. We also focus on the story of cytostatics related to 9-[2-(phosphonomethoxy)ethyl]guanine and its prodrugs which eventually led to development of the veterinary drug rabacfosadine. Various new ANP structures are also currently investigated as antiparasitics, especially antimalarial agents e.g., guanine and hypoxanthine derivatives with 2-(phosphonoethoxy)ethyl moiety, their thia-analogues and N-branched derivatives. In addition to ANPs and their analogs, we also describe prodrugs of 2-(phosphonomethyl)pentanedioic acid (2-PMPA), a potent inhibitor of the enzyme glutamate carboxypeptidase II (GCPII), also known as prostate-specific membrane antigen (PSMA). Glutamate carboxypeptidase II inhibitors, including 2-PMPA have been found efficacious in various preclinical models of neurological disorders which are caused by glutamatergic excitotoxicity. Unfortunately its highly polar character and hence low bioavailability severely limits its potential for clinical use. To overcome this problem, various prodrug strategies have been used to mask carboxylates and/or phosphonate functionalities with pivaloyloxymethyl, POC, ODOL and alkyl esters. Chemistry and biological characterization led to identification of prodrugs with 44-80 fold greater oral bioavailability (tetra-ODOL-2-PMPA).

Cidofovir, a choice for salvage treatment of CMV infection in patients with haploidentical hematopoietic stem cell transplantation

BACKGROUND

Cidofovir (CDV) is a nucleotide analogue with broad antiviral activities. It remains unclear about the CDV administration for anti-cytomegalovirus (CMV) treatment in patients with haploidentical hematopoietic stem cell transplantation (haplo-HSCT).

PATIENTS AND METHODS

In this study, 31 out of 101 haplo-HSCT recipients suffered CMV infection in the CT group (conventional treatment) were enrolled into the CDV-ST group (CDV-second-line treatment). These patients were treated with CDV as they failed conventional treatment or they were unavailable to the preemptive antiviral therapy. Nine patients with CMV infection were enrolled into the CDV-FT group (CDV-frontline treatment) and received CDV preemptive therapy.

RESULTS

In the CDV-ST group, 23/28(82.1%) patients were observed treatment response with a median time of 9 (2-23) days, and 20 (71.8%) among these patients obtained complete response (CR). In the CDV-FT group, 6/8 (75.0%) patients acquired CR with a median of 6 (4-25) days. The treatment response in CDV-treated groups was comparable with those in CT groups. Besides, there was no statistical difference in CMV-related mortality between the three groups (P>0.05). During the follow-up period (Median follow-up:10 (1-28) months), a total of 8/22 (36.4%) patients experienced CMV reactivation in the CDV-ST group, versus 23/62 (37.1%) in CT group (P>0.05). CDV-related toxicities occurred in 13/40 (32.5%) patients, including 6 (15%) reversible nephrotoxicity.

CONCLUSION

Our study suggests that CDV is potentially an option for the salvage treatment of CMV infection in the haplo-HSCT patients. This article is protected by copyright. All rights reserved.

Efficacy of small-dose ganciclovir on cytomegalovirus infections in children and its effects on liver function and miR-UL112-3p expression

The aim of the study was to explore the efficacy of small-dose ganciclovir on cytomegalovirus infections as well as its effects on the liver function and miR-UL112-3p of children. A total of 141 children infected with cytomegalovirus admitted to the Affiliated Hospital of Weifang Medical University from May 2015 to August 2017 were enrolled, of which 74 children were treated with small-dose ganciclovir as an observation group (Obs group), and the rest were treated with conventional-dose ganciclovir as a control group (Con group). The two groups were compared in efficacy after treatment, changes of liver function indexes [total bilirubin (TB), alanine aminotransferase (ALT), and aspartate aminotransferase (AST)] and miR-UL112-3p before and after treatment, and adverse reactions after treatment. A receiver operating characteristic (ROC) curve was drawn to analyze the value of miR-UL112-3p in predicating efficacy on cytomegalovirus infections in children, and Pearson's correlation analysis was carried out to analyze the correlation between miR-UL112-3p expression and TB, ALT and AST. The MV-DNA level between the two groups after treatment was compared. The two groups showed no significant difference in efficacy and adverse reactions (both P>0.05), and before treatment, there was also no significant difference between the two groups in miR-UL112-3p, TB, ALT, and AST, while after treatment, both groups showed lower levels of miR-UL112-3p, TB, ALT, and AST, and the Obs group showed significantly lower levels thereof than the Con group (all P<0.05). In addition, the area under the curve (AUC), specificity, and sensitivity of miR-UL112-3p in the ROC curve of the Obs group were 0.866, 73.77 and 84.62%, respectively, while the AUC, specificity, and sensitivity of the ROC of the Con group were 0.837, 75.44, and 90.00%, respectively. Furthermore, miR-UL112-3p was positively correlated with TB, ALT, and AST, respectively. The CMV-DNA level in the Obs group was lower than that in the Con group, but the difference was not significant, and the level of CMV-DNA was positively correlated with that of miR-UL112-3p. In conclusion, small-dose ganciclovir can better improve the liver function of the children, and downregulate miR-UL112-3p in them. The AUC, specificity, and sensitivity of miR-UL112-3p for predicting the efficacy of small-dose ganciclovir were 0.866, 73.77 and 84.62%, respectively, and the AUC, specificity, and sensitivityfor predicting the efficacy of conventional-dose ganciclovir were 0.837, 75.44 and 90.00%, respectively.