Clinical features of atypical presentations of mucocutaneous herpes simplex virus infection observed in immunosuppressed individuals. Part I: herpetic geometric glossitis.

Herpetic geometric glossitis is a unique morphologic variant of HSV (herpes simplex virus) type 1 infection on the dorsum of the tongue that presents as an extremely painful linear central lingual fissure with a branched pattern. in the center of the tongue; there is a branched pattern of fissures that extend bilaterally from the central linear fissure. Herpetic geometric glossitis has been reported in 11 patients; 8 of these individuals were immunocompromised. Medical conditions and immunosuppressive medication treatment (7 patients) or only medical disorders (3 patients) or neither (1 patient) were present. HSV type 1 infection was diagnosed by viral culture in (7 patients), Tzanck preparation (2 patients) or clinically (2 patients). Mucocutaneous HSV infection at non-lingual locations--including the lips, labial mucosa, face and chest--were observed in 5 patients. All patients' symptoms and lesions responded to treatment with oral antiviral therapy: acyclovir (9 patients), famciclovir (1 patient) or valacyclovir (1 patient). The lingual pain and dorsal tongue fissures completely resolved completely within two to 14 days. In summary, herpetic geometric glossitis is a unique HSV type 1 infection, usually in immunocompromised patients, that occurs on the dorsal tongue and responds completely after treatment with orally administered antiviral therapy.

FIRST DETECTION OF CLINICAL DISEASE DUE TO ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS 7A IN TWO AFRICAN ELEPHANTS (LOXODONTA AFRICANA) IN HUMAN CARE.

Multiple species of elephant endotheliotropic herpesvirus (EEHV) have caused fatal hemorrhagic disease in African (Loxodonta africana) and Asian (Elephas maximus) elephants. To date, EEHV7 has been detected only in benign pulmonary and skin nodules and in saliva of African elephants and has not been associated with clinical illness. Low-level viremia due to EEHV7A was detected via qPCR in two subadult African elephants during routine surveillance. Hematologic changes were noted in both elephants, including leukopenia, lymphopenia, monocytopenia, and band heterophilia. Treatment was initiated with famciclovir, antimicrobials, and rectal fluids, and one elephant received plasma transfusions due to a progressive decrease in platelet count. Both elephants remained asymptomatic throughout the viremias, with rapid resolution of hematologic abnormalities. These cases add to the current understanding of the epidemiology of EEHV in African elephants; to the authors' knowledge, they represent the first documentation of clinical disease due to EEHV7 infection in any elephant.

A phase 2a open-label clinical trial to determine the effect of famciclovir on EBV activity as measured by EBV shedding in the saliva of patients with multiple sclerosis.

BACKGROUND: Despite increasing evidence that Epstein-Barr virus (EBV) plays a causal role in MS, no treatments have been shown to reduce EBV turnover. We studied the effect of famciclovir on salivary EBV shedding in people with MS (NCT05283551) in a pilot, proof-of-concept study. METHODS: People with MS receiving natalizumab provided weekly saliva samples for 12 weeks before starting famciclovir 500 mg twice daily for 12 weeks. Twelve saliva samples were provided on treatment and 12 following treatment. A real-time qPCR Taqman assay was used to detect EBV DNA in saliva. The proportion of saliva samples containing EBV DNA was compared using the Friedman test. RESULTS: Of 30 participants (19 F; mean age 41 years; median EDSS 3.5), 29 received famciclovir, and 24 completed the 12-week course. Twenty-one participants provided at least one usable saliva sample in all epochs. Ten of the 21 had shedding in at least one sample pre-drug; 7/21 when taking famciclovir (not significant). No difference in EBV DNA copy number was seen. There were no drug-related serious adverse events. CONCLUSION: No significant effect of famciclovir on EBV shedding was seen in this small pilot study. Given the low numbers, a small effect of famciclovir cannot be excluded. Salivary EBV shedding in this natalizumab-treated cohort was lower than in previous studies, which requires replication.

Clinical evaluation of antiviral combination treatment in cats with feline herpesvirus-1 infection.

Feline herpesvirus-1 (FHV-1) can cause lifelong problems such as rhinotracheitis and ocular disease due to latency and reactivation in affected cats. The particular effects of antiviral drugs have been separately investigated in previous studies for decades and little is known about the combination treatment in active FHV-1 infection. Therefore, we aimed to evaluate the effects of antiviral combination on clinical effectiveness in cats with naturally occurring FHV-1 infection. 28 cats suffering from clinical signs of sneezing, nasal congestion, conjunctivitis, and eye/nose discharge were involved in this study following FHV-1 DNA detection by PCR assay in oculo-oropharyngeal samples. The treatment protocol was as follows: oral famciclovir and L-lysine, ophthalmic acyclovir, and subcutaneous amoxicillin plus clavulanic acid. The symptoms improved each day and total recovery success rate was 80% reduction in clinical scores at the end of the treatment on day 10 (p<0.001). Additionally, PCR was found to be negative for FHV-1 DNA in 82.1% of the samples after the treatment. There were mild decreases in neutrophil and monocyte counts (p>0.05). The arginine to lysine ratio decreased in favour of lysine (p<0.01). As a result, the antiviral combination treatment with famciclovir, L-lysine and ophthalmic acyclovir, and antibacterial drug appears to be clinically effective for the treatment of naturally occurring active FHV-1 infection in cats. In addition, any adverse clinical effect has not been determined associated with the antiviral combination during the study.

A Network Meta-Analysis of Randomized Clinical Trials to Assess the Efficacy and Safety of Antiviral Agents for Immunocompetent Patients with Herpes Zoster-Associated Pain.

BACKGROUND: The most refractory symptom of herpes zoster (HZ) is pain. Approximately 90% of people who have HZ suffer from pain. Early use of antiviral medications has been found to reduce pain across all stages of the disease. Although many antiviral agents via oral or intravenous administration were recommended by clinical practice, the best approach to prevent HZ-associated pain remains uncertain. OBJECTIVES: The purpose of this study was to compare the efficacy and adverse events of various antiviral agents used for the treatment of HZ-associated pain through a network meta-analysis. STUDY DESIGN: A systematic review and meta-analysis. SETTING: The Cochrane Register of Controlled Trials, Embase, and PubMed were searched from inception to Feb 2020. METHODS: Randomized clinical trials evaluating antiviral agents currently available for treating HZ-associated pain were included. We extracted data in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and conducted network meta-analyses with random-effects models. The primary outcome was the presence of acute pain at the end of anti-virus treatment, and the secondary outcomes included the presence of pain at 28-30 days after the onset of the acute herpetic rash, the presence of postherpetic neuralgia (PHN), and any other adverse events. RESULTS: A total of 17 randomized control trials with 5,579 participants were included in this study. According to the results of the network meta-analysis, for the treatment of acute pain, there was no significant difference between oral acyclovir and intravenous acyclovir. Furthermore, oral famciclovir was the most effective treatment concerning both the odds ratio (OR) (superior to placebo OR = 0.25; 95% CI: 0.13~0.48) and the surface under the cumulative ranking curve (SUCRA) values of 0.84 for the treatment of acute pain among all the oral antiviral agents. For the presence of pain at 28-30 days, no significant difference was observed in efficacy between all antiviral treatments and placebo concerning the OR; however, oral valaciclovir ranked first (SUCRA values of 0.96). For the presence of NPH, oral famciclovir was determined to be the most effective (SUCRA values of 0.77) treatment with an efficacy of 0.42 (95% CI: 0.18~0.99) versus placebo. For adverse events, there was no significant difference between oral antivirals and placebo; however, intravenous acyclovir ranked last with a score of OR 4.31 (95% CI: 1.26~14.75) versus placebo. LIMITATIONS: The distribution of severity of pain was different in various studies; then, the lack of availability of individual data prevented us from analyzing the effects of the risk factors. CONCLUSIONS: For the treatment of acute pain and PHN, oral famciclovir was the most effective treatment among all the oral antiviral agents. For alleviating pain after 28-30 days, oral valaciclovir appeared to be the most effective among all antiviral agents. Additionally, all oral antiviral agents were well tolerated. CLINICAL TRIAL REGISTRATION INFORMATION: PROSPERO under the identification CRD42020212834.

A Computational Study of Famciclovir Derivatives Against Thymidine Kinase as a Molecular Target for the Development of Novel Anticancer Drugs via Suicide Gene Therapy Concepts.

BACKGROUND: The viral thymidine kinase (TK) phosphorylates the antiviral medication famciclovir (FCV), which treats herpes simplex virus (HSV-TK). The phosphorylated FCV destroys the infected cells by preventing cellular DNA synthesis. OBJECTIVE: We hypothesize that FCV impurity, which is a related substance to FCV, should be efficient in killing cells independent of HSV-TK and is currently the most widely used suicide agent for gene therapy of cancer. METHODS: This study proposes the binding affinity of these derivatives for the active site of TK through molecular docking to a protein (PDB ID: 1W4R). The derivatives' reliability was ensured through the in-silico preliminary drug designing model by screening their Lipinski rule of five violations, if any, ADMET prediction for their profile using online tools. Using MOE 2009.10 computational software, we performed molecular docking of approximately 22 famciclovir derivatives alongside the famciclovir drug. RESULTS: Our results suggest that these derivatives are indicative of possible chemical stability irrespective of all the parameters used to evaluate the selected derivatives as a possible drug candidates for their cytotoxicity. FC20 (i.e., 2-(2-(2-((1-(9-(4-Acetoxy-3-(acetoxymethyl)butyl)-2-amino-9Hpurin- 8-yl)ethyl)amino)-9H-purin-9-yl)ethyl)propane-1,3-diyl diacetate) and FC21 (i.e., 2-Amino-1,9- dihydro-9-(4-hydroxybutyl)-6H-purin-6-one), showed maximum and minimum scores of -26.95 and - 7.21 kcal/mol, respectively when compared to famciclovir (-15.4122 kcal/mol). CONCLUSION: Considering that there might be a cytotoxicity effect due to competition between protein TK and the suicidal gene of famciclovir derivatives. The outcome of the study proved that the FCV impurity could successfully modify an HSV-TK-dependent antiviral drug into an anti-tumor drug. Further, it can be used for the design and development of novel compounds of FCV impurity that could be cytotoxic agents if properly delivered to cancer cells.

Formulation Optimization and Evaluation of Nanocochleate Gel of Famciclovir for the Treatment of Herpes Zoster.

BACKGROUND: Herpes zoster is a viral infection triggered due to the reactivation of the varicella- zoster virus in the posterior dorsal root ganglion. Herpes zoster infections occur mostly in the facial, cervical and thoracic regions of the body, beginning with pain and resulting in the vesicular eruption. Recently, this infection was observed during the COVID-19 pandemic and also after the induction of mRNA-based vaccine for coronavirus at an extended level. Nanocochleates are cylindrical (cigarshape) microstructure lipid-based versatile carriers for drug delivery systems. Famciclovir is an antiviral agent employed for the treatment of Herpes zoster infections. OBJECTIVE: The current research patent aims to develop a novel nanocochleate gel of Famciclovir for the treatment of herpes zoster infections with higher efficacy. METHODS: The interaction studies using FTIR were carried out and indicated no such interactions between the drug and lipids. The nanocochleates were developed using hydrogel, trapping, liposome before cochleate dialysis, direct calcium dialysis and binary aqueous-aqueous emulsion methods, respectively. The 32 Box-Behnken design was applied by considering the concentration of lipids (phosphatidylcholine and cholesterol) and speed of rotation as independent factors, whereas particle size and entrapment efficiency as dependable factors. RESULTS: The developed nanocochleates were estimated for the particle size (276.3 nm), zeta potential (-16.7 mV), polydispersity index (0.241), entrapment efficiency (73.87±0.19%) and in vitro diffusion release (>98.8% in 10 h). The optimized batch was further converted into the topical gel using carbopol 940 as a gelling agent. The prepared gel was smooth, rapidly spreadable with a viscosity (5998.72 cp), drug content (95.3%) and remained stable during stability studies. CONCLUSION: A novel nanocochleate gel of Famciclovir was successfully developed for the treatment of infections associated with Herpes Zoster with sustained release action.

Evaluation of compounded cidofovir, famciclovir, and ganciclovir for the treatment of feline herpesvirus ocular surface disease in shelter-housed cats.

OBJECTIVE: To assess the efficacy of compounded cidofovir, famciclovir, and ganciclovir for the treatment of feline herpesvirus type 1 (FHV-1) ocular surface disease. ANIMALS STUDIED: 132 shelter-housed cats qPCR positive for FHV-1. PROCEDURES: A masked placebo-controlled study design was utilized. Animals were enrolled in one of four treatment groups: topical ocular placebo + oral placebo (n = 32), compounded cidofovir 0.5% ophthalmic solution + oral placebo (n = 32), compounded famciclovir oral solution (90 mg/kg) + topical ocular placebo (n = 32), and compounded ganciclovir 0.15% ophthalmic solution + oral placebo (n = 36). Cats were treated with each medication twice daily for 7 days and were evaluated on Day 1 and Day 8 using an ocular scoring system, body weight, and qPCR for FHV-1 viral load. RESULTS: Cidofovir significantly decreased viral load from Day 1 to Day 8 compared with placebo (p = .024). Neither famciclovir nor ganciclovir decreased viral load compared with placebo (p = .14, p = .41). There was no significant improvement of ocular scores for any drug group compared with placebo (p = .62). In all groups, 65%-75% of cats improved from Day 1 to Day 8. Juvenile cats had a significant increase in weight gain compared with placebo for cidofovir (p = .025) and ganciclovir (p = .023). All corneal ulcers in placebo animals failed to heal whereas 77% of ulcers in antiviral group animals healed. CONCLUSIONS: Topical ophthalmic cidofovir significantly decreased ocular FHV-1 viral shedding and increased weight gain in juvenile cats. Ganciclovir increased weight gain in juvenile cats. Compounded famciclovir demonstrated limited efficacy for the treatment of FHV-1 ocular surface disease in shelter-housed cats.

[Efficacy and safety of different doses of antiviral agents in the treatment of herpes zoster: a meta-analysis].

Objective: To systematically evaluate the efficacy and safety of different doses of antiviral drugs in the treatment of herpes zoster. Methods: PubMed, EMBASE, Cochrane Library, VIP, CNKI and WanFang database up to April 9, 2022 were searched. Two reviewers selected the studies according to inclusion and exclusion criteria, and the Cochrane bias risk assessment tool was used for quality evaluation. Data were analyzed by Revman 5.4 software for meta-analysis. The qualitative data used relative risk (RR) as the effect index, and the quantitative data used mean difference (MD) as the effect index. The point estimates and 95%CI of each effect were given. Results: Fourteen randomized controlled trials with 1 831 patients were included in the study. Compared with the 200 mg acyclovir with five times a day, the 800 mg can improve the effective rate, shorten the blister stopping time (MD=-1.29, 95%CI:-1.62- -0.96, P<0.001), relieve the pain faster (MD=-2.73, 95%CI:-4.37- -1.09, P=0.001), shorten the scabbing time (MD=-2.42, 95%CI:-2.96- -1.89, P<0.001) without increasing the adverse reaction rate (RR=1.64, 95%CI:0.80-3.36, P=0.17); Compared with the 300 mg valaciclovir with twice daily, the 900-1 000 mg valaciclovir with three times a day can improve the effective rate(RR=1.17, 95%CI:1.04-1.32, P=0.007), shorten the blister stopping time (MD=-1.53, 95%CI:-2.54- -0.51, P=0.003), relieve the pain faster (MD=-1.04, 95%CI:-1.30- -0.77, P<0.001), shorten the scabbing time (MD=-1.78, 95%CI:-2.80- -0.76, P<0.001), reduce the incidence of postherpetic neuralgia(RR=0.28, 95%CI:0.15-0.52, P<0.001) without increasing the adverse reaction rate (RR=1.47, 95%CI:0.93-2.32, P=0.10); In immunocompromised patients, compared with 1 000 mg valaciclovir with three times a day, 2 000 mg cannot significantly improve the treatment efficacy. There was no significant difference among the efficacy of 250 mg, 500 mg and 750 mg famciclovir, three times a day, in the treatment of herpes zoster. Conclusion: The 800 mg acyclovir with five times a day; 900-1 000 mg valaciclovir and 250 mg famciclovir with three times a day, are better choices in the treatment of herpes zoster.

14-day famciclovir treatment significantly reduces the incidence of postherpetic neuralgia in elderly patients with herpes zoster.

WHAT IS KNOWN AND OBJECTIVE: Pain is the main symptom of herpes zoster (HZ), whilst postherpetic neuralgia (PHN) is a long-term unbearable pain, which seriously affects the quality of life of patients and is also the most intractable problem for clinicians. Early antiviral treatment is considered as a key measure to reduce acute pain and PHN. Nevertheless, most patients still have long-term pain after 7 days of antiviral treatment, and some patients will develop PHN. This study aimed to investigate whether prolonged duration of antiviral therapy could reduce HZ acute pain and the occurrence of PHN. METHODS: The outpatient data of HZ patients over 50 years old who visited the Dermatology Department from January 2016 to May 2018 were retrospectively analysed. According to the different courses of treatment of famciclovir (FCV), the patients were divided into 7-day FCV group and 14-day FCV group. The numerical rating scale (NRS) score at the first visit and on the 7th, 14th and 21st days after the start of treatment, the adverse drug reactions and the incidence of PHN were compared between the two groups. RESULTS: A total of 219 patients were involved in the analysis. For acute pain control, the 14-day FCV group was better than the 7-day FCV group. For patients with mild initial pain, there was no significant difference in NRS between the two treatments. For patients with moderate-to-severe initial pain, the NRS in the 14-day FCV group was significantly lower than that of the 7-day FCV group on the 14th and 21st days after starting treatment. PHN occurred in patients with moderate-to-severe initial pain, and the incidence was significantly lower in the 14-day FCV group than in the 7-day FCV group. There was no significant difference in the number of adverse reactions between the two groups. WHAT IS NEW AND CONCLUSION: Compared with the traditional 7-day antiviral therapy, the 14-day course of FCV can reduce the acute pain and the incidence of PHN in elderly patients with HZ, especially in patients with moderate to severe initial pain. Prolonging the course of medication did not increase the side effects.

Antiviral treatment in outpatients with herps zoster in six major areas of China, 2010-2019.

Objective: The objective of this study was to assess the status and trends of antiviral treatment in outpatients with herpes zoster in China. Methods: Prescription data on antiviral drugs were extracted from the database of the Hospital Prescription Analysis Program of China according to the inclusion criteria. Yearly prescriptions and costs were calculated, and trends were analyzed. The trends were further stratified by age, sex, and specific drug use. The distribution of defined daily costs (DDCs) of valaciclovir and famciclovir were analyzed, and trends in the median DDCs were identified. Results: A total of 132,911 prescriptions from 49 hospitals located in six major areas of China were included in the analysis. The yearly prescriptions containing antivirals increased from 8,819 in 2010 to 16,361 in 2019. The percentage of prescriptions for patients aged 65 years and above also increased (27.7% in 2010 to 31.0% in 2019), and the number of prescriptions for females was higher than those for males (P < 0.001). The average cost of antivirals per prescription decreased; thus, the yearly cost showed no increasing trend. The main prescribed antivirals were valaciclovir and famciclovir, which progressively increased in prescriptions. The use of acyclovir decreased during the study period. Prescriptions containing topical formulations, acyclovir and penciclovir, both increased. The DDCs of valaciclovir and famciclovir decreased dramatically. Conclusion: The use of antivirals has increased over the decade, while the cost has not. Antiviral treatments adhere well to recent recommendations, except for the use of topical antivirals. The findings of this study may benefit the healthcare source allocation and management of herpes zoster in China.

Comparative Efficacy of Topical Ophthalmic Ganciclovir and Oral Famciclovir in Cats with Experimental Ocular Feline Herpesvirus-1 Epithelial Infection.

Purpose: To determine the comparative efficacy of ganciclovir ophthalmic gel and famciclovir oral tablets in cats with experimentally induced ocular feline herpesvirus-1 (FHV-1) epithelial infection. Methods: A randomized, placebo-controlled trial was performed using 16 nonvaccinated, specific pathogen-free cats with experimental FHV-1 infection induced by topical ocular inoculation. Cats received topical ganciclovir 0.15% ophthalmic gel (1 drop 3 times daily, n = 6 cats), oral famciclovir (90 mg/kg twice daily, n = 6), or topical artificial tear gel (1 drop 3 times daily, n = 4) for 14 days. Cats were monitored after inoculation for 30 days. Ophthalmic examinations were performed every 2 days and ocular disease scores calculated. In vivo confocal microscopy was performed, and corneal leukocyte infiltrates quantified. Ocular samples for FHV-1 quantitative polymerase chain reaction (qPCR) and virus isolation assays were collected every 3 days. Hemograms and serum biochemistry panels were performed at intervals. Results: Clinical ocular disease scores and corneal leukocyte infiltrates were significantly lower in the ganciclovir and famciclovir groups compared with placebo, but no significant differences were detected between the antiviral treatment groups. Ocular viral loads determined by qPCR were significantly lower in the ganciclovir group compared with the placebo group, but there were no significant differences between the other study groups. Hemograms and biochemistry panels were unremarkable. Conclusion: Topical application of ganciclovir gel 3 times daily was well-tolerated and displayed similar efficacy at reducing clinical ocular disease scores and corneal inflammation as twice daily oral famciclovir treatment in cats with experimental ocular FHV-1 infection.

NOVEL DIAGNOSTIC AND THERAPEUTIC APPROACHES TO ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS 1A HEMORRHAGIC DISEASE IN A CAPTIVE JUVENILE ASIAN ELEPHANT (ELEPHAS MAXIMUS).

Novel diagnostic and therapeutic methods were utilized in the successful management of severe elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD) in a 1.9-yr-old captive Asian elephant (Elephas maximus). High levels of EEHV1A viremia were detected for 12 d. In addition to established EEHV treatments, therapies included famciclovir-fortified elephant whole blood and plasma, mesenchymal stem cells harvested from elephant umbilical tissue, and aminocaproic acid. Testing conducted to examine the effects of EEHV infection on hemostasis suggested marked intravascular coagulation with decreased plasminogen activity and increased D-dimer concentrations. Thromboelastography was used to assess the efficacy of aminocaproic acid and demonstrated hypofibrinolysis on samples taken after drug administration, as compared with samples from healthy adult Asian elephants. A serological assay for a novel EEHV1A-specific antibody marker (E52) was developed due to lack of seroconversion to a previously established EEHV1A-specific antibody marker (ORFQ) and showed a sustained increase after EEHV-HD illness.

Evaluation of low dose famciclovir as herpes simplex virus and varicella zoster virus prophylaxis in cytomegalovirus low-risk solid organ transplant recipients.

OBJECTIVE: Famciclovir is a recommended option for herpes simplex virus (HSV) and varicella-zoster virus (VZV) prophylaxis in cytomegalovirus (CMV) low-risk solid organ transplant (SOT) recipients in current guidelines; however there is currently no data evaluating its use in SOT recipients. We conducted a multicenter provider survey on antiviral prophylaxis in CMV low-risk SOT recipients and evaluated the efficacy and safety of once daily famciclovir antiviral prophylaxis. METHODS: Two-part analysis consisting of a national provider survey and a retrospective chart review of 78 kidney transplant recipients at a single institution. RESULTS: Providers from 45 transplant centers within the United States responded to the survey. Across all organs, acyclovir 400 mg twice daily was utilized by the majority of respondents (70.4%), with most using prophylaxis for a duration of 3 months (68.8%). No respondents reported use of famciclovir at their institution. In the retrospective review there were no documented cases of HSV/VZV/CMV infection during the 3 months of famciclovir prophylaxis, and only one patient (1.3%) later developed VZV infection at 12 months post-transplant. One patient (1.3%) required premature discontinuation of famciclovir due to concern for acute interstitial nephritis. CONCLUSION: Nationwide, the most common antiviral prophylaxis used in CMV low-risk SOT recipients is acyclovir 400 mg twice daily. Among patients receiving once daily famciclovir for CMV low-risk antiviral prophylaxis, there was no HSV/VZV/CMV infection while on prophylaxis. Once daily famciclovir may provide an effective and convenient once daily dosing regimen for antiviral prophylaxis in CMV low-risk SOT recipients.

Variable accuracy, precision, and consistency of compounded famciclovir formulated for management of feline herpesvirus-1 in cats.

OBJECTIVE: To evaluate compounded famciclovir suspensions for accuracy, precision, and consistency in drug content. PROCEDURES: Two compounded famciclovir concentrations were evaluated (250 and 400 mg/mL, 30 preparations total from nine 503A compounding pharmacies) with U.S. Food and Drug Administration (FDA)-approved famciclovir tablets as control. Drug quantification via high-performance liquid chromatography (with famciclovir reference standard and pramipexole internal standard) was performed at 0, 14, and 28 days with concentrations of 90%-110% of labeled dose considered acceptable (US Pharmacopoeia standards). RESULTS: FDA-approved tablets from three different manufacturers were found to be accurate and precise with acceptable drug content. A significantly greater mean deviation from labeled content was noted for 400 mg/mL suspensions (-52.9%) compared to 250 mg/mL suspensions (-18.0%). When assessing time points separately, 15/63 (24%) samples of 250 mg/mL and 0/27 (0%) samples of 400 mg/mL suspensions met the acceptance standards. Coefficients of variation (CV) in drug content among pharmacy batches ranged from 0.5% to 29%, with 5/10 formulations having significantly lower CV% compared to control (decreased precision). Similarly, drug content changed over time (0-28 days) in all compounded formulations, with both downward and upward trends observed (variable consistency). CONCLUSIONS: Most compounded famciclovir formulations were inaccurate, imprecise, and inconsistent. FDA-approved famciclovir tablets may be preferred over compounded famciclovir formulations for the management of feline herpesvirus-1. If compounded famciclovir is used in practice, a concentration of 250 mg/mL is preferred over 400 mg/mL given the lower accuracy of the higher concentration.

Feline conjunctival microbiota in a shelter: effects of time, upper respiratory disease and famciclovir administration.

OBJECTIVES: The aim of this study was to evaluate changes in the conjunctival microbiota of shelter-housed cats with time, upper respiratory disease (URD) and famciclovir administration. METHODS: Cats were assigned to treatment groups on shelter entry. Healthy cats or cats with URD received ~30 mg/kg or ~90 mg/kg of famciclovir or placebo PO q12h for 7 days, or were untreated. Swabs were collected from ventral conjunctival fornices prior to (day 1) and immediately after (day 8) the treatment period. Microbiota analysis was conducted on 124 randomly selected swabs from healthy (56 swabs) or URD-affected (68 swabs) cats. Following DNA extraction and amplification of the V4 region of the 16S rRNA gene, sequences were assembled into operational taxonomic units (OTUs). Over-represented OTUs (as determined by linear discriminate analysis effect size), alpha and beta diversity, and median relative abundance of known feline ocular surface pathogens were assessed for the entire population and in 10 clinically relevant subpopulations of cats. RESULTS: Bacteria from 33 phyla and 70 genera were identified. Considering all cats, median relative abundance of Mycoplasma increased from day 1 to day 8, while Proteobacteria decreased. Community membership and structure (beta diversity) differed between days 1 and 8 for all famciclovir-treated cats (regardless of health status or dose) and healthy or URD-affected cats (regardless of famciclovir dose). Differences in taxonomic diversity within a sample (alpha diversity) between day 1 and day 8 were not detected in any subpopulations. CONCLUSIONS AND RELEVANCE: Within 1 week of shelter entry, there were significant changes in community structure and membership of the feline conjunctival microbiota, with a shift towards over-representation of feline ocular surface pathogens. Although famciclovir may impact beta diversity of the feline conjunctival microbiota, absence of change in alpha diversity suggests minimal shift in individual cats.

Drug content on receipt and over time for compounded formulations of famciclovir.

OBJECTIVES: The aim of this study was to determine famciclovir content (strength) in compounded formulations and to determine if potency changed over time. METHODS: Four concentrations of oral oil suspension in three distinct flavors, three concentrations of oral paste, three chew treats and 62.5 mg tablets from one compounding pharmacy were evaluated for famciclovir content. Specific sample preparation procedures were used for each drug formulation prior to determination of famciclovir content through mass spectrometry tandem liquid chromatography. Analysis was performed on arrival from the compounder and on days 7, 14, 28, 56 and 120. Samples were run in triplicate and concentration determined by comparison with a standard curve. Content was considered appropriate if within 90-110% of the labeled concentration. RESULTS: On arrival from the compounding pharmacy, 5/12 oral oil suspensions of varying concentrations were <90% of the labeled concentration and 3/3 oral pastes were >110%. Famciclovir content in oil suspensions ranged from 72% to 118% of the label value while oral pastes ranged from 95% to 202% of the label concentration over the 120 study days, and all concentrations varied in an unpredictable fashion. Tablets contained 90-110% of the labeled value throughout the study period. Chew treats could not be successfully analyzed. CONCLUSIONS AND RELEVANCE: This study found substantial variation in famciclovir content in the compounded products evaluated, which, in turn, raises concerns that substandard dosing could result in lack of efficacy or a failed treatment trial. Drug toxicity might also be encountered. Veterinarians must be aware that while compounded medications can improve compliance, they might not deliver the drug dose expected.

Successful treatment with famciclovir for varicella zoster virus infection resistant to acyclovir.

Varicella zoster virus (VZV) reactivates more frequently in immunocompromised patients than immunocompetent subjects and is a significant cause of morbidity and mortality. Acyclovir is frequently used for treatment against VZV reactivation. However, long-term use of acyclovir can result in the emergence of VZV strain resistant to acyclovir. Here, we report a 67-year-old man with adult T-cell leukemia who suffered from herpes zoster with acyclovir-resistant VZV after long-term prophylaxis. The isolated viruses from his skin lesions were a mixture of acyclovir-resistant and acyclovir-susceptible strains. Sequence analysis showed the presence of thymidine kinase (TK) mutations in the resistant clones. Interestingly, oral administration of famciclovir, a prodrug form of penciclovir, resulted in resolution of his herpes zoster, although most acyclovir-resistant strains of VZV were reported to be resistant to penciclovir. This implied that a certain amount of susceptible VZV with wild-type viral TK gene was present in vivo, and that famciclovir could be phosphorylated intracellularly by the intact viral kinases. As famciclovir is more potent and longer-acting than acyclovir, the susceptible strains might have suppressed the generation and proliferation of the resistant in vivo. Even when VZV is developing resistance to acyclovir, famciclovir might be effective at least in the early resistant phase.

Prediction of Kidney Drug Clearance: A Comparison of Tubular Secretory Clearance and Glomerular Filtration Rate.

BACKGROUND: Although proximal tubular secretion is the primary mechanism of kidney drug elimination, current kidney drug dosing strategies are on the basis of eGFR. METHODS: In a dedicated pharmacokinetic study to compare GFR with tubular secretory clearance for predicting kidney drug elimination, we evaluated stable outpatients with eGFRs ranging from 21 to 140 ml/min per 1.73 m2. After administering single doses of furosemide and famciclovir (metabolized to penciclovir), we calculated their kidney clearances on the basis of sequential plasma and timed urine measurements. Concomitantly, we quantified eight endogenous secretory solutes in plasma and urine using liquid chromatography-tandem mass spectrometry and measured GFR by iohexol clearance (iGFR). We computed a summary secretion score as the scaled average of the secretory solute clearances. RESULTS: Median iGFR of the 54 participants was 73 ml/min per 1.73 m2. The kidney furosemide clearance correlated with iGFR (r=0.84) and the summary secretion score (r=0.86). The mean proportionate error (MPE) between iGFR-predicted and measured furosemide clearance was 30.0%. The lowest MPE was observed for the summary secretion score (24.1%); MPEs for individual secretory solutes ranged from 27.3% to 48.0%. These predictive errors were statistically indistinguishable. Penciclovir kidney clearance was correlated with iGFR (r=0.83) and with the summary secretion score (r=0.91), with similar predictive accuracy of iGFR and secretory clearances. Combining iGFR with the summary secretion score yielded only modest improvements in the prediction of the kidney clearance of furosemide and penciclovir. CONCLUSIONS: Secretory solute clearance measurements can predict kidney drug clearances. However, tight linkage between GFR and proximal tubular secretory clearance in stable outpatients provides some reassurance that GFR, even when estimated, is a useful surrogate for predicting secretory drug clearances in such patients.

Famciclovir leads to failure of hematopoiesis, but may have the benefit of relieving myeloid expansion in MDS-like zebrafish.

Famciclovir (FCV) is an antiviral drug that is often utilized after bone marrow transplantation to prevent viral infection. Yet, its role in hematopoiesis is poorly understood. Here, by utilizing a zebrafish model, we found that FCV exposure led to hematopoietic failure by impairing the proliferation of hematopoietic stem and progenitor cell (HSPC) and inducing HSPC apoptosis. On the other hand, FCV treatment could effectively relieve myeloid malignancies in the c-mybhyper MDS-like fish model, and played a role not only in the embryonic stage but also in adult zebrafish. This study reveals that FCV functions as a double-edged sword, with hematotoxicity at a high level, but that appropriate FCV treatment may be beneficial for the treatment of MDS.