Penciclovir pharmacokinetics after oral and rectal administration of famciclovir in African elephants (Loxodonta africana) shows that effective concentrations can be achieved from rectal administration, despite lower absorption

OBJECTIVE

To evaluate the pharmacokinetics of famciclovir and its metabolite penciclovir following a single dose administered orally and rectally in African elephants (Loxodonta africana).

ANIMALS

15 African elephants (6 males and 9 females) of various ages.

METHODS

Famciclovir (15 mg/kg) was administered orally or per rectum once, with at least a three-week washout period between administrations. Blood was collected at 13 different timepoints per administration for 6 elephants, occurring between February and March 2020. An additional 9 elephants were sampled at variable timepoints per administration utilizing a sparse sampling design between July 2020 and January 2021. Plasma famciclovir and penciclovir levels were measured via HPLC and fluorescence detection. Pharmacokinetic analysis was completed in the summer of 2021 using noncompartmental analysis and nonlinear mixed-effects modeling.

RESULTS

Famciclovir was not detected in any sample, suggesting complete metabolism. Key pharmacokinetic parameters for penciclovir following oral administration were time to maximum concentration (tmax; 2.12 hours), area under the concentration-versus-time curve (AUC; 33.93 μg·h/mL), maximum observed concentration (Cmax; 3.73 μg/mL), and absorption half-life (t1/2; 0.65 hours). Following rectal administration, the values were: tmax, 0.65 hours; AUC, 15.62 μg·h/mL; Cmax, 2.52 μg/mL; and absorption t1/2, 0.13 hours.

CONCLUSIONS

Famciclovir was rapidly metabolized to penciclovir. Oral administration resulted in slower absorption but higher maximum plasma concentration and higher AUC compared to rectal administration.

CLINICAL RELEVANCE

African elephants administered famciclovir via oral and rectal routes resulted in measurable serum penciclovir, and these findings may be utilized by clinicians treating viral infections in this species.

Surveillance for feline herpesvirus type 1 mutation and development of resistance in cats treated with antiviral medications

Feline herpesvirus type 1 (FHV-1) commonly causes ocular surface disease in cats and is treated with antiviral medications targeting viral DNA polymerase (UL30/42). Herein, we describe a method to assess the FHV-1 genome for mutation development and to assess the functional impact of mutations, if present. Fourteen shelter-housed domestic cats with FHV-1 ocular surface disease were assigned to one of four treatment groups: placebo (n = 3), cidofovir 0.5% ophthalmic solution (n = 3), famciclovir oral solution (n = 5), or ganciclovir 0.15% ophthalmic solution (n = 3). Swabs were collected before (day 1) and after (day 8) 1 week of twice-daily treatments to isolate viable FHV-1. Viral DNA was extracted for sequencing using Illumina MiSeq with subsequent genomic variant detection between paired day 1 and day 8 isolates. Plaque reduction assay was performed on paired isolates demonstrating non-synonymous variants. A total of 171 synonymous and 3 non-synonymous variants were identified in day 8 isolates. No variants were detected in viral UL23, UL30, or UL42 genes. Variant totals were not statistically different in animals receiving antiviral or placebo (p = 0.4997). A day 8 isolate from each antiviral treatment group contained a single non-synonymous variant in ICP4 (transcriptional regulator). These 3 isolates demonstrated no evidence of functional antiviral resistance when IC₅₀ was assessed. Most (10/14 pairs) day 1 and 8 viral isolate pairs from the same host animal were near-identical. While functional variants were not detected in this small sample, these techniques can be replicated to assess FHV-1 isolates suspected of having developed resistance to antiviral medications.

Comparison of a One- versus Two-Week Treatment with Famciclovir Upon Reductions in Pain and Occurrence of Postherpetic Neuralgia in Herpes Zoster: A Randomized Open-Label Trial

Background

Herpes zoster (HZ) is an acute herpetic skin disease resulting from the varicella-zoster virus. Typically, this condition is treated with a one-week administration of antiviral drugs, including famciclovir, which can effectively control the symptoms during the acute phase and prevent the occurrence of postherpetic neuralgia (PHN).

Objective

To investigate whether a longer, two-week, regimen would enhance the capacity for famciclovir to reduce pain and prevent the occurrence of postherpetic neuralgia.

Methods

HZ patients were randomly divided into two groups who were treated with famciclovir for either a one- or two-week period. Following their respective famciclovir treatments, patients were assessed for potential differences in pain intensity as evaluated at 1, 2, 4, 8 and 12 weeks post-treatment. In addition, the occurrence of postherpetic neuralgia at three months after treatment was compared between the two groups.

Results

Of the 86 patients initially enrolled, 80 completed the study with N=40 randomly assigned to each of the two groups. Pain scores decreased significantly at 1, 2, 4, 8 and 12 weeks after famciclovir treatments. There were no significant differences in pain scores, and the incidence of postherpetic neuralgia occurrence between the two groups. There were no statistically significant differences in reducing pain intensity or frequency of postherpetic neuralgia between the one-week and two-week treatment protocols.

Conclusion

It suggests that longer administration of famciclovir has no further benefit in the treatment of herpes zoster in our study.

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.

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.

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.

Emergence of varicella-zoster virus resistance to acyclovir: epidemiology, prevention, and treatment

Introduction: Acyclovir has led to the development of successful systemic therapy for herpes simplex virus and varicella-zoster virus (VZV) infection, and the use of valacyclovir and famciclovir has improved treatment. Additionally, the use of a helicase-primase (HP) inhibitor (HPI), amenamevir, is changing the treatment of herpes zoster (HZ).Area covered: VZV infection is prevented by vaccines and is treated with antiviral agents. Acyclovir and penciclovir are phosphorylated by viral thymidine kinase and work as chain terminators. Improvements in the management of immunocompromised patients have reduced severe and prolonged immunosuppression and chronic VZV infection with acyclovir-resistant mutants has become rarer. The HP is involved in the initial step of DNA synthesis and amenamevir has novel mechanisms of action, efficacy to acyclovir-resistant mutants, and pharmacokinetic characteristics. The literature search for PUBMED was conducted on 10 April 2020 and updated on 4 November 2020.Expert opinion: Amenamevir has been used to treat HZ in Japan. Although the number of patients with VZV infection will decrease owing to the use of vaccines, the addition of HPI will improve treatment and treatment options for resistant viruses. The clinical use of HPIs in addition to current nucleoside analogs opens a new era of antiherpes therapy.

Herpes Zoster Co-Infection in an Immunocompetent Patient With COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a broad spectrum of manifestations. A variety of dermatological manifestations were described. We present a case of an immunocompetent middle-aged man who presented with novel coronavirus disease 2019 (COVID-19) and later developed herpes zoster (HZ). The case highlights the possibility of COVID-19-related HZ. The highest infection control measures must be abided when managing patients with cutaneous complaints until COVID-19 is ruled out.

Effects of famciclovir in cats with spontaneous acute upper respiratory tract disease

OBJECTIVES

The aim of this study was to assess the effects of famciclovir administration in cats with spontaneously acquired acute upper respiratory tract disease.

METHODS

Twenty-four kittens with clinical signs of acute upper respiratory tract disease were randomly allocated to receive doxycycline (5 mg/kg PO q12h) alone (group D; n = 12) or with famciclovir (90 mg/kg PO q12h; group DF; n = 12) for up to 3 weeks. Clinical disease severity was scored at study entry and daily thereafter. Oculo-oropharyngeal swabs collected at study entry and exit were assessed using quantitative PCR for nucleic acids of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), Chlamydia felis, Bordetella bronchiseptica and Mycoplasma felis.

RESULTS

The median (range) age of cats was 1.5 (1-6) months in group D vs 1.6 (1-5) months in group DF (P = 0.54). Pathogens detected in oculo-oropharyngeal swabs at study entry included FCV (n = 13/24; 54%), M felis (n = 8/24; 33%), FHV-1 (n = 7/24; 29%), C felis (n = 7/24; 29%) and B bronchiseptica (n = 3/24; 12%). Median (range) duration of clinical signs was 11.5 (3-21) days in group DF and 11 (3-21) days in group D (P = 0.75). Median (range) total disease score at the end of the study did not differ between groups (group D 1 [1-1] vs group DF 1 [1-3]; P = 0.08).

CONCLUSIONS AND RELEVANCE

This study revealed no significant difference in response to therapy between cats treated with doxycycline alone or with famciclovir; cats improved rapidly in both groups. However, identification of FHV-1 DNA was relatively uncommon in this study and clinical trials focused on FHV-1-infected cats are warranted to better evaluate famciclovir efficacy.

Clinical Trial of Herbal Treatment Gene-Eden-VIR/Novirin in Oral Herpes

Background.

Our previous articles showed that suppressive or preventive treatment with the herbal Gene-Eden-VIR/Novirin reduced the number and duration of genital herpes outbreaks with no adverse effects. These studies also revealed that the herbal Gene-Eden-VIR/Novirin is mostly superior to acyclovir, valacyclovir, and famciclovir drugs in genital herpes. This study tested the effect of Gene-Eden-VIR/Novirin in oral herpes (also called cold sores and fever blisters).

Methods.

The framework of the study was a retrospective chart review. The study included 68 participants. The participants took 1 to 4 capsules per day over a period of 2 to 36 months. The study included 2 Food and Drug Administration–recommended controls: baseline and a no-treatment.

Results.

Gene-Eden-VIR/Novirin was effective in 89.3% of participants. The treatment reduced the mean number of outbreaks per year from 6.0 and 3.6 in the control groups to 2.0 in the treatment group (P < .0001 and P = .07, respectively). Gene-Eden-VIR/Novirin reduced the mean duration of outbreaks from 9.8 and 5.8 days in the control groups to 3.2 days in the treatment group (P < .0001 and P = .02, respectively). There were no reports of adverse experiences. Gene-Eden-VIR/Novirin was compared to acyclovir and valacyclovir in 6 tests. In all tests, Gene-Eden-VIR/Novirin showed higher efficacy. Gene-Eden-VIR/Novirin also showed superior safety.

Conclusions.

This clinical study showed that suppressive or preventive treatment with the herbal Gene-Eden-VIR/Novirin reduced the number and duration of outbreaks in oral herpes without any adverse effects. The study also showed that the herbal Gene-Eden-VIR/Novirin had better clinical effects than acyclovir and valacyclovir, the leading drugs in the category. Based on these results, we recommend using the herbal Gene-Eden-VIR/Novirin as preventive treatment for oral herpes and, specifically, as an alternative to the acyclovir and valacyclovir drugs.

A famciclovir + celecoxib combination treatment is safe and efficacious in the treatment of fibromyalgia

Objective

Infections and other stressors have been implicated in the development of fibromyalgia. We hypothesized that these stressors could result in recurrent reactivations of latent herpes virus infections, which could lead to the development of fibromyalgia. This study evaluated a famciclovir + celecoxib drug combination (IMC-1), active against suspected herpes virus reactivation and infection, for the treatment of fibromyalgia.

Methods

A total of 143 fibromyalgia patients were enrolled at 12 sites in a 16-week, double-blinded, placebo-controlled proof-of-concept trial. Randomized patients received either IMC-1 or placebo in a 1:1 ratio. Outcome measures included a 24-hour recall pain Numerical Rating Scale, the Revised Fibromyalgia Impact Questionnaire (FIQ-R), the Patient’s Global Impression of Change (PGIC) questionnaire, the Multidimensional Fatigue Inventory, the NIH Patient-Reported Outcomes Measurement Information System (PROMIS), and the Beck Depression Inventory-II conducted at baseline and weeks 6, 12, and 16 of the study.

Results

A significant decrease in fibromyalgia-related pain was observed for patients on IMC-1 treatment versus placebo. PGIC response rates were significantly improved with IMC-1 treatment. Overall, patient self-reported functioning, as measured by the FIQ-R, was significantly improved. Fatigue was also significantly improved as measured by the PROMIS fatigue inventory. The safety profile was encouraging. Despite the celecoxib component of IMC-1, gastrointestinal and nervous system treatment emergent adverse events were reported less frequently in the IMC-1 group, and study completion rates favored IMC-1 treatment.

Conclusion

IMC-1 was efficacious and safe in treating symptoms of fibromyalgia, supporting the hypothesis that herpes virus infections may contribute to this syndrome. Improved retention rates, decreased adverse event rates, and evidence of efficacy on a broad spectrum of outcome measures are suggestive that IMC-1 may represent an effective, novel treatment for fibromyalgia.

Clinical study in genital herpes: natural Gene-Eden-VIR/Novirin versus acyclovir, valacyclovir, and famciclovir

BACKGROUND

This paper reports the results of a clinical study that tested the effect of suppressive treatment with the botanical product Gene-Eden-VIR/Novirin on the number of genital herpes outbreaks. The results in this study were compared to those published in clinical studies of acyclovir, valacyclovir, and famciclovir.

METHODS

The framework was a retrospective chart review. The population included 139 participants. The treatment was one to four capsules of Gene-Eden-VIR/Novirin per day. The duration of treatment was 2-48 months. The study included three controls recommended by the US Food and Drug Administration (FDA): baseline, no treatment, and dose response.

RESULTS

The treatment decreased the number of outbreaks per year in 90.8% of the participants. The treatment also decreased the mean number of outbreaks per year from 7.27 and 5.5 in the control groups to 2.39 (P<0.0001 and P<0.001, respectively). The treated participants reported no adverse experiences. Out of the 15 tests that compared Gene-Eden-VIR/Novirin to the three drugs, Gene-Eden-VIR/Novirin had superior efficacy in eight tests, inferior efficacy in three tests, and comparable efficacy in four tests. Gene-Eden-VIR/Novirin also had superior safety.

CONCLUSION

The clinical study showed that the natural Gene-Eden-VIR/Novirin decreases the number of genital herpes outbreaks without any side effects. The study also showed that the clinical effects reported in this study are mostly better than those reported in the reviewed studies of acyclovir, valacyclovir, and famciclovir.

Surviving and fatal Elephant Endotheliotropic Herpesvirus-1A infections in juvenile Asian elephants - lessons learned and recommendations on anti-herpesviral therapy

Background

Elephant Endotheliotropic Herpesviruses (EEHVs) can cause acute haemorrhagic disease in young Asian elephants (Elephas maximus) and clinical EEHV infections account for the majority of their fatalities. The anti-herpesviral drug famciclovir (FCV) has been used routinely to treat viraemic at-risk elephants, but thus far without proven efficacy. This paper presents clinical and virological investigations of two EEHV-1A infected elephants treated with FCV, and discusses anti-herpesvirus therapies of viraemic elephants.

Cases presentations

Two 1.5 year old male Asian elephants at a zoological collection in the UK developed clinical EEHV-1A infections. Case 1 showed signs of myalgia for the duration of 24 hours before returning back to normal. EEHV-1A DNAemia was confirmed on the day of clinical signs and continued to be present for 18 days in total. Trunk shedding of the virus commenced 10 days after detection of initial DNAemia. Case 2 tested positive for EEHV-1A DNAemia in a routine blood screening sample in the absence of clinical signs. The blood viral load increased exponentially leading up to fatal clinical disease seven days after initial detection of DNAemia. Both calves were treated with 15 mg/kg FCV per rectum on detection of DNAemia and penciclovir, the FCV metabolite, could be detected in the blood at assumed therapeutic levels. The early indicators for clinical disease were a marked absolute and relative drop in white blood cells, particularly monocytes prior to the detection of viraemia. The most prognostic haematological parameter at later stages of the disease was the platelet count showing a continuous sharp decline throughout, followed by a dramatic drop at the time of death.

Conclusions

The EEHV-1A viraemic animals investigated here further highlight the ongoing threat posed by these viruses to juvenile Asian elephants. The findings call into question the efficacy of rectal FCV in clinical cases and direct towards the use of alternative anti-herpesvirus drugs and complementary treatments such as plasma infusions if no improvement in either viral load or the above-mentioned blood parameters are observed in the initial days of viraemia despite anti-herpesvirus therapy.

The changing landscape of antiviral treatment of herpes zoster: a 17-year population-based cohort study

BACKGROUND

Herpes zoster (HZ) is a common viral disease that produces a painful vesicular rash. Early use of antiviral medications is recommended, as it reduces pain and speeds healing. A population-based observational study was conducted to evaluate the changing burden of HZ in the province of Manitoba (Canada) over a period of 17 years.

METHODS

Administrative health care data including medical and hospital records were examined, and International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification codes were used to identify episodes of HZ between April 1, 1997 and March 31, 2014 in persons aged 20 or over. Annual age-adjusted incidence and hospitalization rates were calculated. Prescription records of HZ-diagnosed persons for acyclovir, valacyclovir, and famciclovir were used to calculate the rates and costs of antiviral treatment.

RESULTS

There were 73,893 identified cases of HZ and 1,245 HZ-related hospitalizations between 1997 and 2013. Of these episodes, 42,270 (57.2%) were treated with antiviral medications at a total cost of $4,708,065 (CAD). The age-adjusted incidence of HZ rose from 4.67/1,000 person years in 1997/1998 to 5.67/1,000 person years in 2013/2014, a 21.9% increase. Antiviral treatment rates increased from 41.7% to 66.2% of all diagnosed episodes. Mean treatment costs per episode dropped from $127.29 in 1997/1998 to $56.06 in 2013/2014, primarily due to the introduction of generic antiviral medications. The total cost of antiviral treatment peaked in 2005/2006 at $329,935 and dropped steadily thereafter to $223,973 in 2013/2014. HZ-related hospitalization rates decreased from 3.1% to 0.9%.

CONCLUSION

While both the incidence of HZ and the rates of antiviral treatment have risen substantially, the economic burden from antiviral treatment has been decreasing since a peak in 2005/2006 and was only 3.2% higher in 2013/2014 than in 1997/1998. This drop in cost is attributed to the introduction of generic antiviral drugs.

TREATMENT OF CHRONIC HERPESVIRAL DERMATITIS IN A CAPTIVE CHEETAH (ACINONYX JUBATUS) IN NAMIBIA

A 9-yr-old male cheetah (Acinonyx jubatus) housed at the Cheetah Conservation Fund in Namibia developed cutaneous lesions consisting of alopecia, erythema, ulceration, and crusting on the left fore and hind limbs. Histopathology of skin biopsies in conjunction with indirect fluorescent antibody and polymerase chain reaction testing confirmed a diagnosis of feline herpesvirus-1 dermatitis; microbial culture indicated secondary bacterial infection. Therapy included targeted systemic antimicrobial and antiviral treatment, topical medications, and repeated cryotherapy. Lesions exhibited varying degrees of clinical improvement but, overall, progressed in extent, size, and severity during the subsequent 2.5 yr of intense treatment. The cheetah was ultimately euthanized due to a guarded prognosis and concerns about poor quality of life. Potential factors initiating or contributing (or both) to the severity and nonhealing nature of the cutaneous lesions include chronic unidentified stress, altered immune system function, and other environmental influences.

Oral antiviral therapy for prevention of genital herpes outbreaks in immunocompetent and nonpregnant patients

BACKGROUND

Genital herpes is caused by herpes simplex virus 1 (HSV-1) or 2 (HSV-2). Some infected people experience outbreaks of genital herpes, typically, characterized by vesicular and erosive localized painful genital lesions.

OBJECTIVES

To compare the effectiveness and safety of three oral antiviral drugs (acyclovir, famciclovir and valacyclovir) prescribed to suppress genital herpes outbreaks in non-pregnant patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the search portal of the World Health Organization International Clinical Trials Registry Platform and pharmaceutical company databases up to February 2014. We also searched US Food and Drug Administration databases and proceedings of seven congresses to a maximum of 10 years. We contacted trial authors and pharmaceutical companies.

SELECTION CRITERIA

We selected parallel-group and cross-over randomized controlled trials including patients with recurrent genital herpes caused by HSV, whatever the type (HSV-1, HSV-2, or undetermined), with at least four recurrences per year (trials concerning human immunodeficiency virus (HIV)-positive patients or pregnant women were not eligible) and comparing suppressive oral antiviral treatment with oral acyclovir, famciclovir, and valacyclovir versus placebo or another suppressive oral antiviral treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible trials and extracted data. The Risk of bias tool was used to assess risk of bias. Treatment effect was measured by the risk ratio (RR) of having at least one genital herpes recurrence. Pooled RRs were derived by conventional pairwise meta-analyses. A network meta-analysis allowed for estimation of all possible two-by-two comparisons between antiviral drugs.

MAIN RESULTS

A total of 26 trials (among which six had a cross-over design) were included. Among the 6950 randomly assigned participants, 54% (range 0 to 100%) were female, mean age was 35 years (range 26 to 45.1), and the mean number of recurrences per year was 11 (range 6.3 to 17.8). Duration of treatment was two to 12 months. Risk of bias was considered high for half of the studies and unclear for the other half. A total of 14 trials compared acyclovir versus placebo, four trials compared valacyclovir versus placebo and 2 trials compared valacyclovir versus no treatment. Three trials compared famciclovir versus placebo. Two trials compared valacyclovir versus famciclovir and one trial compared acyclovir versus valacyclovir versus placebo.We analyzed data from 22 trials for the outcome: risk of having at least one clinical recurrence. We could not obtain the outcome data for four trials. In placebo-controlled trials, there was a low quality evidence that the risk of having at least one clinical recurrence was reduced with acyclovir (nine parallel-group trials, n = 2049; pooled RR 0.48, 95% confidence interval (CI) 0.39 to 0.58), valacyclovir (four trials, n = 1788; pooled RR 0.41, 95% CI 0.24 to 0.69), or famciclovir (two trials, n = 732; pooled RR 0.57, 95% CI 0.50 to 0.64). The six cross-over trials showed larger treatment effects on average than the parallel-group trials. We found evidence of a small-study effect for acyclovir placebo-controlled trials (adjusted pooled RR 0.61, 95% CI 0.49 to 0.75). In analyzing parallel-group trials by daily dose, no clear evidence was found of a dose-response relationship for any drug. In head-to-head trials, the risk of having at least one recurrence was increased with valacyclovir rather than acyclovir (one trial, n = 1345; RR 1.16, 95% CI 1.01 to 1.34) and was not significantly different from that seen with famciclovir as compared with valacyclovir (one trial, n = 320; RR 1.18, 95% CI 0.86 to 1.63).We included 16 parallel-arm trials in a network meta-analysis and we were unable to determine which of the drugs was most effective in reducing the risk of at least one clinical recurrence (after adjustment for small-study effects, pooled RR 0.83, 95% CI 0.61 to 1.11 for valacyclovir vs acyclovir; pooled RR 1.04, 95% CI, 0.71 to 1.49 for famciclovir vs acyclovir; and pooled RR 1.26, 95% CI 0.89 to 1.75 for famciclovir vs valacyclovir). Safety data were sought but were reported as total numbers of adverse events.

AUTHORS' CONCLUSIONS

Owing to risk of bias and inconsistency, there is low quality evidence that suppressive antiviral therapy with acyclovir, valacyclovir or famciclovir in pacients experiencing at least four recurrences of genital herpes per year decreases the number of pacients with at least one recurrence as compared with placebo. Network meta-analysis of the few direct comparisons and the indirect comparisons did not show superiority of one drug over another.

Complications of immunosuppressive/immunomodulatory therapy in neurological diseases

OPINION STATEMENT

The first critical step in the appropriate treatment of neurological infectious disease accompanying immunosuppressive states or immunomodulatory medication is to properly identify the offending organism. Broadly immunosuppressive conditions will predispose to both common and uncommon infectious diseases. There are substantial differences between neurological infectious disorders complicating disturbances of the innate immunity (neutrophils, monocytes and macrophages) and those due to abnormal adaptive immunity (humoral and cellular immunity). Similarly, there are differences in the types of infections with impaired humoral immunity compared to disturbed cellular immunity and between T- and B-cell disorders. HIV/AIDS has been a model of acquired immunosuppression and the nature of opportunistic infections with which it has been associated has been well characterized and generally correlates well with the degree of CD4 lymphopenia. Increasingly, immunotherapies target specific components of the immune system, such as an adhesion molecule or its ligand or surface receptors on a special class of cells. These targeted perturbations of the immune system increase the risk of particular infectious diseases. For instance, natalizumab, an α4β1 integrin inhibitor that is highly effective in multiple sclerosis, increases the risk of progressive multifocal leukoencephalopathy for reasons that still remain unclear. It is likely that other therapies that result in a disruption of a specific component of the immune system will be associated with other unique opportunistic infections. The risk of multiple simultaneous neurological infections in the immunosuppressed host must always be considered, particularly with a failure to respond to a therapeutic regimen. With respect to appropriate and effective therapy, diagnostic accuracy assumes primacy, but occasionally broad spectrum therapy is necessitated. For a number of opportunistic infectious disorders, particularly some viral and fungal diseases, antimicrobial therapy remains inadequate.

Current management and recommendations for access to antiviral therapy of herpes labialis

Herpes labialis is a common skin infective condition, worldwide, which is primarily caused by HSV-1. Recurrent episodes of herpes labialis, also known as cold sores, can be frequent, painful, long-lasting and disfiguring for infected patients. At present, there are two types of antivirals for the treatment of herpes labialis, topical and oral, which are available over the counter or as prescription-only. The aim of antiviral therapy is to block viral replication to enable shortening the duration of symptoms and to accelerate healing of the lesions associated with herpes labialis. This review examines the evidence for the effectiveness of current topical and oral antivirals in the management of recurrent episodes of herpes labialis. In most countries, oral antivirals for herpes labialis are available as prescription-only. However, in early 2010, the oral antiviral famciclovir was reclassified from prescription-only medicine to pharmacist-controlled status in New Zealand. The benefits and risks associated with moving an antiviral therapy for herpes labialis from prescription-only to pharmacist-controlled status are reviewed here, and the implications for patients, general physicians and pharmacists are considered.

Single-day treatment for orolabial and genital herpes: a brief review of pathogenesis and pharmacology

Herpes simplex virus (HSV) infection is a highly prevalent condition responsible for significant morbidity and occasional mortality each year. Approximately half of all patients infected by HSV will experience at least one recurrence in their lifetime. For these recurrences, traditional therapy has included both suppressive and episodic treatment with nucleoside analogs. In regards to episodic treatment, 2- to 5-day oral regimens are best studied and most commonly reported. As with any medical condition having a well-understood mechanism of action and targeted treatment, therapeutic intervention is only as effective as allowed by patient compliance. Based on these concerns, recent studies have focused on shorter, less complicated, and more affordable options. This review delineates the evidence for single-day treatments of orolabial and genital herpes. Randomized, double-blind studies of both valacyclovir and famciclovir as single-day episodic therapy for HSV have been reported in the literature. Although no head-to-head studies between the drugs have been performed, both regimens produced significant improvement in healing time and symptom resolution over placebo. Single-day therapy for HSV infection is appealing for multiple reasons. First, it simplifies the regimen, increasing likelihood of patient compliance. Additionally, it allows complete delivery of the medication at the onset of symptoms, when viral replication is highest and intervention has greatest effect. Lastly, the reduced number of pills necessary for single versus multiple day therapy decreases the overall cost of treatment per episode, an important factor in modern-day healthcare.

Single-day famciclovir for the treatment of genital herpes: follow-up results of time to next recurrence and assessment of antiviral resistance

BACKGROUND

Episodic therapy of genital herpes is usually recommended for patients with infrequent symptomatic recurrences and where transmission is not a concern. While shorter courses are as effective as standard 5-day regimens, it is unknown whether abbreviated therapy has detrimental effects on natural history and the development of antiviral resistance.

OBJECTIVES

To assess time to next recurrence and development of antiviral resistance in patients with recurrent genital herpes treated with either single-day famciclovir (1 g twice-daily) or 3-day valacyclovir (500 mg twice-daily).

METHODS

Longer-term, follow-up data on the time to next recurrence and antiviral sensitivity were collected from a previously reported multicenter, multinational, double-blind, parallel group study in which 1179 immunocompetent adults were randomized 1 : 1 to receive either single-day famciclovir or 3-day valacyclovir. Treatment was self-initiated within 6 hours of a recurrence. Swabs for viral culture and sensitivity testing were collected for two sequential recurrences.

RESULTS

The median time to next recurrence from treatment initiation was 33.5 days for famciclovir and 38.0 days for valacyclovir. No drug resistance to penciclovir, the active metabolite of famciclovir, was observed at baseline nor did any develop by the time of the next recurrence.

LIMITATIONS

The study had no placebo arm, typing of viral isolates was not performed and viral resistance testing was restricted to penciclovir only.

CONCLUSION

Treatment with single-day famciclovir for recurrent genital herpes did not shorten the time to the next recurrence. Drug resistance to penciclovir continues to be a rare event in immunocompetent patients.