Relationship between renal dysfunction and electrolyte abnormalities in hematopoietic stem cell transplant patients treated with foscarnet

Case Report: Maribavir for refractory cytomegalovirus viremia after renal transplantation in a child with Schimke's immune-osseous dysplasia

Cytomegalovirus (CMV) is a major opportunistic pathogen in recipients of solid organ transplantation. Maribavir, a pUL97 protein kinase inhibitor, was approved for the treatment of refractory post-transplant CMV infection in the US in 2021. However, it is rarely used in pediatric patients worldwide. Here, we report the case of a Chinese boy with Schimke's immune-osseous dysplasia (SIOD) who developed refractory CMV infection after a renal transplantation. An 11-year-old boy was hospitalized with recurrent abdominal and testicular pain 50 days after renal transplantation. Diagnoses included urinary tract infection, epididymitis, CMV viremia, stage 2 chronic kidney disease, and SIOD. After five days of treatment, his pain improved, but he developed persistent fever and shortness of breath. Blood CMV levels rose to 1.64 × 105 copies/ml after one month of ganciclovir treatment. Significant bone marrow suppression was observed after combined treatment with foscarnet. Anti-rejection treatment was discontinued due to compromised immune function. On day 40, maribavir was initiated with parental consent, resulting in undetectable CMV copies within four days. The patient's clinical status and bone marrow suppression had improved. Continuing maribavir for two weeks led to the disappearance of CMV viremia, no bone marrow suppression, and normal liver and kidney functions. This case demonstrates the successful short-term use of maribavir in the treatment of refractory CMV infection in an immune-deficient child after renal transplantation. Further studies are required to explore the efficacy and safety of maribavir in pediatric patients.

[Pathophysiology and treatment of acyclovir-resistant herpes simplex virus keratitis]

Herpetic keratitis (HK) caused by herpes simplex virus 1 (HSV-1) is the major cause of infection-related blindness in developed countries. Current treatment is based on curative and preventive use of antiherpetic acyclic nucleoside analogues (ANAs), namely acyclovir (ACV) or other molecules with the same mechanism of action. The frequency of HK caused by acyclovir-resistant viruses is steadily increasing. Virological proof of resistance is obtained from an ocular sample sent to a specialized laboratory. Genotypic characterization by DNA sequencing of the viral enzymes targeted by antivirals allows adaptation of treatment according to the mutation identified. Mutations of the viral thymidine kinase (TK) are the most frequent and leave few viable alternatives for long-term prophylactic treatment among currently available drugs. Amenamevir (AMNV), a new drug targeting the viral helicase-primase (HP) enzyme complex, with proven efficacy for treatment of herpetic infections of other sites, has recently shown value in the management of ACV-resistant HK. Its TK-independent mechanism allows it to retain its antiviral activity even in cases of patient resistance to ACV.

Risk assessment for hypocalcemia in therapeutic apheresis for kidney transplantation

INTRODUCTION

The increase in the number of kidney transplants performed in the United States has been paralleled with an increase in the utilization of therapeutic apheresis (TA) for kidney transplant indications. Hypocalcemia remains a significant contributor to the adverse event in TA. The magnitude of hypocalcemia and its risk factors are scarcely discussed in literature.

METHODS

This is a retrospective cohort review of adults from 18 years and above who received TA for kidney transplant-related indications from January 1, 2017 to December 31, 2022. Data extracted included basic demographics, indication for apheresis, procedure characteristics, serum ionized calcium at the mid and end of procedure and serum creatinine at the beginning of apheresis, and so forth.

RESULTS

Data from 131 patients and 860 sessions of TA were analyzed. Antibody-mediated rejection (69%) and recurrent FSGS (15%) were the leading indications for TA. There were 60 (7%) TA sessions complicated by hypocalcemia. Of these, 53 (88%) occurred in the first session, 5 (8%) occurred in second session while 2 (4%) occurred in the third and subsequent sessions. Female sex, elevated serum creatinine and use of fresh frozen plasma- are the risk factors for hypocalcemia with odd's ratio of 2.34, 7.42, and 5.01, respectively. Binary logistic regression showed that elevated serum creatinine at the commencement of therapy is an independent predictor of hypocalcemia (adjusted odd's ratio = 3.31, p = 0.001).

CONCLUSION

Hypocalcemia is prevalent in this study. Clinical vigilance and tailored procedure will avert adverse consequences.

Differences in safety profiles of anti-herpesvirus medications: a real-world pharmacovigilance study based on the FAERS database

BACKGROUND

Anti-herpesvirus drug safety profiles have not been systematically compared. Understanding variations in adverse events (AEs) could provide reference for rational clinical use.

METHODS

We collected data on acyclovir, ganciclovir, valaciclovir, and foscarnet from the FDA Adverse Event Reporting System (FAERS) database from Q1 2004 to Q3 2023. Disproportionality analyses were conducted to evaluate the risk of AEs.

RESULTS

All drugs exhibited significant associations with hematotoxicity, with ganciclovir and foscarnet being more myelosuppressive. The correlation with renal impairment ranked as follows: foscarnet, ganciclovir, valaciclovir, and acyclovir (ROR = 16.72, 7.06, 3.51, and 2.02, respectively). Regarding hepatotoxicity, ganciclovir was associated with acute-on-chronic liver failure (ROR = 52.83), and foscarnet was associated with fulminant hepatitis (ROR = 49.91). In the nervous system, acyclovir showed the highest intensity of neurotoxicity (ROR = 14.95). Valaciclovir ranked first in toxic encephalopathy (ROR = 64.70). Foscarnet showed the highest intensity of status epilepticus (ROR = 6.45). Besides, acyclovir showed the strongest association with severe cutaneous adverse reactions (SCARs).

CONCLUSIONS

Our study revealed differences in safety profiles of four anti-herpesvirus medications. Ganciclovir exhibited the highest risk of hematotoxicity but appeared relatively safe in seizures and SCARs. Foscarnet was more likely to induce nephrotoxicity, seizures, and electrolyte imbalances than others. Acyclovir and valaciclovir were strongly associated with plasmacytosis, neurotoxicity, and SCARs.

Cost-effectiveness of maribavir versus conventional antiviral therapies for post-transplant refractory cytomegalovirus infection with or without genotypic resistance: A US perspective

This study evaluated the cost-effectiveness of maribavir versus investigator-assigned therapy (IAT; valganciclovir/ganciclovir, foscarnet, or cidofovir) for post-transplant refractory cytomegalovirus (CMV) infection with or without resistance. A two-stage Markov model was designed using data from the SOLSTICE trial (NCT02931539), real-world multinational observational studies, and published literature. Stage 1 (0-78 weeks) comprised clinically significant CMV (csCMV), non-clinically significant CMV (n-csCMV), and dead states; stage 2 (78 weeks-lifetime) comprised alive and dead states. Total costs (2022 USD) and quality-adjusted life years (QALYs) were estimated for the maribavir and IAT cohorts. An incremental cost-effectiveness ratio was calculated to determine cost-effectiveness against a willingness-to-pay threshold of $100 000/QALY. Compared with IAT, maribavir had lower costs ($139 751 vs $147 949) and greater QALYs (6.04 vs 5.83), making it cost-saving and more cost-effective. Maribavir had higher acquisition costs compared with IAT ($80 531 vs $65 285), but lower costs associated with administration/monitoring ($16 493 vs $27 563), adverse events (AEs) ($11 055 vs $16 114), hospitalization ($27 157 vs $33 905), and graft loss ($4516 vs $5081), thus making treatment with maribavir cost-saving. Maribavir-treated patients spent more time without CMV compared with IAT-treated patients (0.85 years vs 0.68 years), leading to lower retreatment costs for maribavir (cost savings: -$42 970.80). Compared with IAT, maribavir was more cost-effective for transplant recipients with refractory CMV, owing to better clinical efficacy and avoidance of high costs associated with administration, monitoring, AEs, and hospitalizations. These results can inform healthcare decision-makers on the most effective use of their resources for post-transplant refractory CMV treatment.

Treatment for First Cytomegalovirus Infection Post-Hematopoietic Cell Transplant in the AURORA Trial: A Multicenter, Double-Blind, Randomized, Phase 3 Trial Comparing Maribavir With Valganciclovir

BACKGROUND

Neutropenia may limit the use of valganciclovir treatment for cytomegalovirus (CMV) infection following hematopoietic cell transplant (HCT). A phase 2 study indicated efficacy of maribavir with fewer treatment-limiting toxicities than valganciclovir.

METHODS

In this multicenter, double-blind, phase 3 study, patients with first asymptomatic CMV infection post-HCT were stratified and randomized 1:1 to maribavir 400 mg twice daily or valganciclovir (dose-adjusted for renal clearance) for 8 weeks with 12 weeks of follow-up. The primary endpoint was confirmed CMV viremia clearance at week 8 (primary hypothesis of noninferiority margin of 7.0%). The key secondary endpoint was a composite of the primary endpoint with no findings of CMV tissue-invasive disease at week 8 through week 16. Treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

Among patients treated (273 maribavir; 274 valganciclovir), the primary endpoint of noninferiority of maribavir was not met (maribavir, 69.6%; valganciclovir, 77.4%; adjusted difference: -7.7%; 95% confidence interval [CI]: -14.98, -.36; lower limit of 95% CI of treatment difference exceeded -7.0%). At week 16, 52.7% and 48.5% of patients treated (maribavir and valganciclovir, respectively) maintained CMV viremia clearance without tissue-invasive disease (adjusted difference: 4.4%; 95% CI: -3.91, 12.76). With maribavir (vs valganciclovir), fewer patients experienced neutropenia (16.1% and 52.9%) or discontinued due to TEAEs (27.8% and 41.2%). Discontinuations were mostly due to neutropenia (maribavir, 4.0%; valganciclovir, 17.5%).

CONCLUSIONS

Although noninferiority of maribavir to valganciclovir for the primary endpoint was not achieved based on the prespecified noninferiority margin, maribavir demonstrated comparable CMV viremia clearance during post-treatment follow-up, with fewer discontinuations due to neutropenia. Clinical Trials Registration. NCT02927067 [AURORA].

At-Home Foscarnet Administration in Patients with Cytomegalovirus Infection Post-Allogeneic Stem Cell Transplantation: A Unicentric, Safe, and Feasible Program

Cytomegalovirus (CMV) infection is a relevant cause of morbimortality in patients receiving allogeneic stem cell transplantation (allo-HCT). Foscarnet (FCN) is an effective drug against CMV administered intravenously and usually on an inpatient basis. The Home Care Unit (HCU) for hematologic patients at our hospital designed an at-home FCN administration model to avoid the hospitalization of patients requiring FCN treatment. This study analyzes whether the at-home administration of FCN is as safe and effective as its hospital administration. We collected and compared demographic, clinical, analytical, and economic data of patients with CMV infection post-allo-HCT who received FCN in the hospital (n = 16, 17 episodes) vs. at-home (n = 67, 88 episodes). The proportions of patients with cured CMV infections were comparable between the two groups (65.9% vs. 76.5%, p = 0.395). The median duration of FCN treatment was 15 (interquartile range [IQR] 9-23) and 14 (IQR 11-19) days in the HCU and inpatient cohorts, respectively (p = 0.692). There were no significant differences in the FCN toxicities between groups except for hypocalcemia (26.1% vs. 58.8%, p = 0.007), which was more prevalent in the inpatient cohort. A significant cost-effectiveness was found in the HCU cohort, with a median savings per episode of EUR 5270. It may be concluded that home administration of FCN is a safe, effective, and cost-efficient therapeutic option for patients with CMV infection and disease.

Once Daily Foscarnet is Effective for HHV-6 Reactivation after Hematopoietic Stem Cell Transplantation

BACKGROUND

Human herpesvirus 6 (HHV-6) reactivation is common after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with higher mortality and transplant-related complications.

OBJECTIVES

We hypothesized that preemptive treatment with short course of foscarnet at lower cut point of plasma HHV-6 viral load would be effective in treating early HHV-6 reactivation, prevent complications and hospitalization of these patients.

METHODS

We reviewed outcomes of adult patients (18 years or older) who received preemptive treatment with once daily foscarnet 60-90 mg/kg for 7 days for HHV-6 reactivation after allo-HSCT at our institution between 05/2020-11/2022. Plasma HHV-6 viral load was monitored using quantitative polymerase chain reaction twice monthly in the first 100 days post-transplant and twice weekly after reactivation until resolution.

RESULTS

Eleven patients with a median age of 46 years (range, 23-73) were included in the analysis. Ten patients received HSCT from a haploidentical and one patient from HLA matched related donor. The most common diagnosis was acute leukemia (9 cases). Myeloablative- and reduced-intensity conditioning regimens were used in 4 cases and 7 cases, respectively. Most patients (10/11) received post-transplantation cyclophosphamide-based graft-versus-host disease prophylaxis. Median follow-up was 440 days (range, 174-831). Median time to HHV-6 reactivation was 22 days post-transplantation (range, 15-89), median level of viral load 3,100 copies/mL (range, 210-118,000) at first reactivation and median peak viral load was 11,300 copies/mL (range, 600-983,000). All patients received a short course of foscarnet of 90 mg/kg/day (N=7) and 60 mg/kg/day (N=4). Plasma HHV-6 DNA in all patients became undetected after completion of one week treatment. No HHV-6 encephalitis or pneumonitis occurred. All patients achieved neutrophil and platelet engraftment after a median time of 16 (range, 8-22) and 26 (range, 14-168) days, respectively, with no secondary graft failure. No complications related to foscarnet administration were noted. One patient with very high HHV-6 viremia had recurrent reactivation and received a second course of foscarnet as outpatient.

CONCLUSIONS

Short course of once daily foscarnet is effective in treating early HHV-6 reactivation post-transplant, may reduce incidence of HHV-6-related and treatment-related complications, and prevent hospitalization in these patients.

Antiviral drugs

In this chapter, we have reviewed side effects reported with the use of antivirals for the treatment of the following infections: coronavirus disease 2019 (COVID-19), cytomegalovirus (CMV), hepatitis B virus (HBV), hepatitis C Virus (HCV), herpes simplex viruses 1 and 2 (HSV-1, -2), human immunodeficiency virus (HIV), and influenza virus. The search engines PUBMED, EMBASE and International Pharmaceutical Abstracts (IPA) were utilized to identify literature published between January 1, 2021 to December 31, 2021.

Detection of human herpes virus 6 DNA and chromosomal integration after allogeneic hematopoietic stem cell transplantation: a retrospective single center analysis

INTRODUCTION

Human herpes virus 6 (HHV-6) can reactivate after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and may be associated with significant morbidity and mortality.

METHODS

The epidemiology of HHV-6 infections and their impact on outcome after allo-HSCT were retrospectively analyzed in 689 adult allo-HSCT recipients (January 2015-December 2018). Chromosomal integration of HHV-6 (ciHHV-6) in the donor was retrospectively investigated to critically evaluate antiviral treatment strategies.

RESULTS

HHV-6 DNA in any specimen was found in 89 patients. HHV-6 infections (encephalitis (1), gastroenteritis (44), dermatitis (2), hepatitis (1) or pneumonitis (5)) were diagnosed in 53/689 patients (7.7%). Elevated levels of HHV-6 DNA were found in 38 patients (5.5%). CiHHV-6, analyzed in patients with HHV-6 viral loads ≥10⁴ copies/mL, was identified in 4 patients (10/38 patients; 10.5%). Two of those displayed copy numbers of HHV-6 ranging from ≥ 2 × 10⁵ to 2.5 × 10⁶ copies/mL (HHV-6A). Here, ciHHV-6 was integrated into donor and not into the patients' cells. In this series of allo-HSCT recipients, 10.5% of patients with blood viral loads of HHV-6 showed ciHHV-6.

CONCLUSION

Screening of the donor for chromosomal integration of HHV-6 (ciHHV-6) before initiation of antiviral therapy is recommended. This article is protected by copyright. All rights reserved.