Use of acyclovir, valacyclovir, and famciclovir in the first trimester of pregnancy and the risk of birth defects

CONTEXT

Herpes simplex and herpes zoster infections are common and often treated with antiviral drugs including acyclovir, valacyclovir, and famciclovir. Safety of these antivirals when used in the first trimester of pregnancy is insufficiently documented.

OBJECTIVE

To investigate associations between exposure to acyclovir, valacyclovir, and famciclovir in the first trimester of pregnancy and risk of major birth defects.

DESIGN, SETTING, AND PARTICIPANTS

Population-based historical cohort study of 837,795 live-born infants in Denmark from January 1, 1996, to September 30, 2008. Participants had no diagnoses of chromosomal aberrations, genetic syndromes, birth defect syndromes with known causes, or congenital viral infections. Nationwide registries were used to ascertain individual-level information on dispensed antiviral drugs, birth defect diagnoses (categorized according to a standardized classification scheme), and potential confounders.

MAIN OUTCOME MEASURE

Prevalence odds ratios (PORs) of any major birth defect diagnosed within the first year of life by exposure to antiviral drugs.

RESULTS

Among 1804 pregnancies exposed to acyclovir, valacyclovir, or famciclovir in the first trimester, 40 infants (2.2%) were diagnosed with a major birth defect compared with 19,920 (2.4%) among the unexposed (adjusted POR, 0.89; 95% confidence interval [CI], 0.65-1.22). For individual antivirals, a major birth defect was diagnosed in 32 of 1561 infants (2.0%) with first-trimester exposure to acyclovir (adjusted POR, 0.82; 95% CI, 0.57-1.17) and in 7 of 229 infants (3.1%) with first-trimester exposure to valacyclovir (adjusted POR, 1.21; 95% CI, 0.56-2.62). Famciclovir exposure was uncommon (n = 26), with 1 infant (3.8%) diagnosed with a birth defect. Exploratory analyses revealed no associations between antiviral drug exposure and 13 different subgroups of birth defects, but the number of exposed cases in each subgroup was small.

CONCLUSION

In this large nationwide cohort, exposure to acyclovir or valacyclovir in the first trimester of pregnancy was not associated with an increased risk of major birth defects.

One-day famciclovir vs. placebo in patient-initiated episodic treatment of recurrent genital herpes in immunocompetent Black patients

BACKGROUND

There are no known racial differences in genital herpes disease pathogenesis or response to therapy. Despite high herpes simplex virus (HSV) seroprevalence in Black persons, clinical trials investigating the treatment of recurrent genital herpes (RGH) have typically enrolled a small proportion of Black patients.

METHODS

This multicenter, double-blind, placebo-controlled study evaluated the efficacy and safety of patient-initiated, 1-day famciclovir 1000 mg twice-daily in immunocompetent Black adults (USA and South Africa) with RGH. Eligible patients were randomized (2:1) to famciclovir or placebo. The primary endpoint was time to healing of non-aborted genital herpes lesions (i.e., lesions that progressed beyond papule stage). Secondary endpoints included proportion of patients with aborted genital herpes lesions, time to resolution of associated symptoms, and safety.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov ; trial identifier NCT00477334.

RESULTS

A total of 299 patients with RGH (66% female, median age = 37 years) received either 1-day famciclovir 1000 mg twice-daily (n = 201) or placebo (n = 98). In the modified intent-to-treat population, the estimated median time to healing of non-aborted genital herpes lesions was 5.38 days for famciclovir and 4.79 days for placebo (median of treatment differences = 0.26 days; 95% CI [-0.40, 0.98]; p = 0.416). Consistent findings were reported in the completer and per-protocol populations. No significant differences were reported for all secondary analyses. Adverse events (AEs) were consistent with the established safety profile of famciclovir: 18 (6%) patients had drug-related AEs (16 [8%] famciclovir; 2 [2%] placebo), none of which were serious or led to discontinuation or dose adjustment/interruption. There are some limitations of this research: many study sites either lacked prior experience in conducting clinical studies in patients with HSV infection or enrolled small numbers of patients, which may have compromised efficacy outcomes. Also, HIV antibody testing was not mandated at enrollment.

CONCLUSION

This study showed similar efficacy and tolerability of 1-day treatment with famciclovir 1000 mg twice-daily compared to placebo in immunocompetent Black adults with RGH. Famciclovir has proven efficacy and safety in the overall RGH population. Further understanding of the efficacy of antiherpes therapy in Black patients with recurrent genital herpes may be warranted.

Improved outcome of chronic hepatitis B after heart transplantation by long-term antiviral therapy

Chronic hepatitis B progresses to cirrhosis in the majority of immunosuppressed patients. The outcome of long-term antiviral therapy in HBV-infected organ transplant recipients is unknown. In 1996, we included 20 heart transplant (HT) recipients in a pilot trial to treat chronic hepatitis B with famciclovir. At that time, bridging fibrosis or cirrhosis was evident in 15 individuals (75%). From 1998 onwards, patients were switched to lamivudine in case of primary or secondary virological nonresponse to famciclovir. Adefovir or tenofovir became available at our centre for HT recipients in 2002. After 103 months, one patient was still on famciclovir showing a complete virological response. Sixteen patients were switched to lamivudine after 0.5-4 years of famciclovir therapy. Six of those showed a long-term response to lamivudine therapy lasting for up to 7 years. Lamivudine resistance developed in the remaining 10 patients (63%), in 4 of them successful rescue therapy (adefovir n = 3, tenofovir n = 1) could be initiated. Only one hepatocellular carcinoma developed, which was successfully treated by locoregional ablative therapy. Nine patients died (45%), with lamivudine-resistance-related liver failure as the cause of death in five cases. Significant improvement of Ishak fibrosis scores could be demonstrated in six of the seven patients with more than two sequential liver biopsies available. Long-term antiviral therapy of chronic hepatitis B can lead to regression of liver cirrhosis in patients after organ transplantation, unless viral resistance occurs. This study demonstrates the urgent need for further antivirals to overcome antiviral resistance.

Comparative efficacy of famciclovir and valacyclovir for suppression of recurrent genital herpes and viral shedding

BACKGROUND

Daily antiviral therapy with famciclovir and valacyclovir has been shown to be effective in reducing both symptomatic and asymptomatic reactivation of herpes simplex virus type 2 (HSV-2) when compared to placebo. However, few comparative studies between the 2 antivirals have been performed.

OBJECTIVES

To compare the clinical and virologic effects of famciclovir and valacyclovir administered as daily suppressive therapy for persons with genital herpes.

STUDY DESIGN

Two randomized, double-blind, placebo-controlled studies comparing daily famciclovir 250 mg bid with valacyclovir 500 mg qd were performed. Study 1 randomized 320 participants and compared the clinical effect of the drugs given for 16 weeks, and study 2 enrolled 70 HSV-2 seropositive subjects and compared the virologic effect of the drugs given for 10 weeks.

RESULTS

In study 1, the time to first recurrence was similar in famciclovir and valacyclovir recipients, hazard ratio (HR) 1.17 (95% CI, 0.78-1.76), but time to first virologically confirmed recurrence was shorter among famciclovir recipients, HR = 2.15 (95% CI, 1.00-4.60). In study 2, HSV was detected on 3.2% of days among famciclovir recipients and 1.3% of days among valacyclovir recipients, relative risk 2.33 (95% CI, 1.18-4.89).

CONCLUSION

Valacyclovir appear to be somewhat better than famciclovir for suppression of genital herpes and associated shedding. Further comparative trials of antiviral drugs for various indications should be performed as acyclovir and penciclovir appear to have different ability to abrogate HSV reactivation.

Famciclovir

Famciclovir (Famvir) is the oral prodrug of penciclovir, an agent that has demonstrated antiviral activity against herpes simplex viruses, type 1 (HSV-1) and 2 (HSV-2) [which cause orolabial and/or genital herpes simplex], and against varicella zoster virus (VZV) [a reactivation of which leads to herpes zoster]. Famciclovir has efficacy similar to that of aciclovir (in immunocompetent or immunocompromised patients) or valaciclovir (in immunocompetent patients) in the treatment of herpes zoster, and efficacy similar to aciclovir in the treatment of first or recurrent episodes of genital herpes (in immunocompetent or immunocompromised patients). Famciclovir also has efficacy in the suppression of recurrent episodes of genital herpes, and in the treatment of orolabial herpes, in immunocompetent patients. As such, famciclovir is a well tolerated first-line option for the treatment of herpes zoster and the treatment and suppression of genital herpes, and is approved for the treatment of recurrent orolabial herpes. Convenient patient-initiated single-day (for recurrent genital herpes) and single-dose (for orolabial herpes) dosage regimens may contribute to treatment compliance, patient acceptability and subsequent treatment outcomes.

Clinic-Initiated, Twice-Daily Oral Famciclovir for Treatment of Recurrent Genital Herpes: A Randomized, Double-Blind, Controlled Trial

BACKGROUND

Famciclovir, the oral prodrug of penciclovir, is effective for the treatment of recurrent genital herpes. This randomized, clinic-initiated, double-blind trial compared the therapeutic efficacy and safety of treatment with famciclovir at dosages of 125 mg, 250 mg, and 500 mg twice daily for 5 days with placebo in immunocompetent adults with a recurrent episode of genital herpes.

METHODS

Efficacy and tolerability were assessed in 308 patients with lesions present for no more than 6.5 h at the time of the first dose. Two assessments per day were performed to increase the precision of the determination of study end points.

RESULTS

All doses of famciclovir were significantly more effective than placebo in reducing the time to cessation of viral shedding, complete lesion healing, and loss of all lesion-associated symptoms, particularly lesion tenderness, pain, and itching. Patients receiving treatment with famciclovir were significantly less likely to experience new lesions than were patients receiving placebo. All doses of famciclovir were tolerated as well as placebo was. There was no difference in efficacy or tolerability among the different doses of famciclovir; the lowest effective dose was 125 mg twice per day.

CONCLUSIONS

In immunocompetent adults with recurrent genital herpes, a 5-day course of famciclovir at a dosage of 125 mg, 250 mg, or 500 mg twice per day was significantly more effective than was placebo in reducing the duration of viral shedding and symptoms and in accelerating lesion healing. These results support the use of treatment with famciclovir at a dosage of 125 mg for 5 days as an effective, well-tolerated treatment for episodes of recurrent genital herpes.

Case reports: cutaneous small vessel vasculitis due to famciclovir therapy

Cutaneous hypersensitivity vasculitis is often idiopathic, but may be the result of therapeutic drugs. It is important to be aware of previously unreported drugs that may be associated with this complication. We report a case of cutaneous hypersensitivity vasculitis due to famciclovir therapy. To our knowledge, this is the first report of this interaction in the medical literature in English.

[Clinical investigation of famciclovir in chronic hepatitis B patients irresponsive to alpha interferon treatment]

OBJECTIVES

To evaluate the efficacy and safety of famciclovir on the decreasing levels of serum HBV-DNA and ALT and HBeAg/antiHBe seroconversion in chronic hepatitis B patients irresponsive to 3 months treatment with alpha interferon.

METHODS

Two hundred and nineteen patients with chronic HBV infection, defined as positive HBsAg, HBeAg and HBV DNA, were enrolled and randomly half-and- half put into famciclovir and placebo groups. The two groups received either famciclovir 500 mg tid or a placebo treatment for 24 weeks, and then were followed-up for another 24 weeks with no treatment.

RESULTS

At the end of 24 weeks, the log value of HBV DNA dropped from 6.54+/-1.26 to 5.70+/-2.03 in the famciclovirt group and were elevated from 6.30+/-1.32 to 6.51+/-1.65 in the placebo group (P < 0.01). The rate of cases with persistence HBV DNA dropped 2 log of quantity in the famciclovir group and was 28.28% (28/99); it was 9.47% (9/95) in the placebo group (P < 0.01). Those with persistence negative HBV DNA was 28.28% (28/99) in the flamciclovir treated group and 14.74% (14/95) in the placebo group (P < 0.05). Those persistently being HBeAg negative were 7.69% (7/91) in the famciclovir treated group and 3.33% (3/90) in the placebo group (P > 0.05). The HBeAg/antiHBe seroconversion was 4.40% (4/91) in the famciclovir group and 2.22% (2/90) in the placebo group (P > 0.05). The percentage of cases with normal of ALT level was 15.15% in the famciclovir group and 6.35% in the placebo group (P < 0.05).

CONCLUSION

Famciclovir is effective in inhibiting HBV DNA replication and in decreasing serum ALT levels. The rate of HBeAg/antiHBe seroconversion in the famciclovir treated group was similar to that of the placebo group. Famciclovir was well tolerated without severe adverse effects during our treatment.

Treatment of postherpetic neuralgia

Postherpetic neuralgia (PHN) is a serious complication of herpes zoster that has a predilection for older individuals. PHN is often associated with significant morbidity, and it can cause insomnia, fatigue, depression and interference with daily activities in affected individuals. Treatment for PHN is initiated with antivirals during the acute herpes zoster outbreak. Acyclovir (Zoviraxr, GlaxoSmithKline), valacyclovir (Valtrex, GlaxoSmithKline) or famciclovir (Famvir, Novartis) can be used to treat herpes zoster, and all three have been shown to reduce the duration of the herpetic rash and zoster-associated pain. These antivirals are most effective when used within the first 72 hours of the onset of the rash. Side-effects of these antivirals are low and include nausea, vomiting, abdominal pain and headache. Other treatment options for PHN include topical analgesics, opioid analgesics, tricyclic antidepressants and gabapentin. Because of the complexity of PHN, most patients require a combination of treatment modalities for adequate pain relief.

Once, twice, or three times daily famciclovir compared with aciclovir for the oral treatment of herpes zoster in immunocompetent adults: a randomized, multicenter, double-blind clinical trial

BACKGROUND

Famciclovir, the well absorbed oral pro-drug of penciclovir, is effective in the treatment of herpes zoster when given three times daily. Because the intracellular half-life of penciclovir triphosphate in varicella-zoster virus (VZV)-infected cells (7h) is considerably longer than that of aciclovir triphosphate (1h), it may be possible to administer famciclovir less frequently than three times daily for herpes zoster: aciclovir is administered five times daily.

METHODS

559 immunocompetent adults presenting with herpes zoster whose skin lesions were present for less than 72 h were randomized to receive famciclovir 750 mg once daily (od), 500 mg twice daily (bid), or 250 mg three times daily (tid), or aciclovir 800 mg five times daily. All treatments were given for 7 days. Participants were evaluated until complete healing or for 4 weeks, whichever occurred first.

RESULTS

There were no significant differences between the four treatment groups with respect to times to full crusting; loss of vesicles, ulcers and crusts; cessation of new lesion formation; a 50% reduction in the area of affected skin; and the loss of acute pain.

CONCLUSIONS

Famciclovir 750 mg once daily, 500 mg twice daily and 250 mg daily, and aciclovir 800 mg five times daily are three times comparable in efficacy with respect to the cutaneous healing of herpes zoster. The current study was not designed to assess the effects of the treatments on postherpetic neuralgia (PHN).

Double-blind, randomized, acyclovir-controlled, parallel-group trial comparing the safety and efficacy of famciclovir and acyclovir in patients with uncomplicated herpes zoster

This randomized, double-blind, parallel-group study compared the efficacy and safety of famciclovir administered at 250 mg thrice daily with acyclovir 800 mg 5 times daily for the treatment of acute uncomplicated herpes zoster in immunocompetent adults. A total of 55 patients participated in this trial. Twenty seven patients (49.1%) were randomized into the famciclovir plus placebo treatment group and 28 (50.9%) into the acyclovir plus placebo group. Six of the 55 patients did not complete the study. Two of these patients were in the famciclovir plus placebo group and dropped out due to deviation from the study protocol. Four patients in the acyclovir plus placebo group did not complete the study protocol due to adverse events (n = 2), deviation from the protocol (n = 1), or loss to follow-up (n = 1). Treatment was initiated within 72 h of onset of the zoster rash and was continued for 7 days. When treatment was initiated within 72 h, famciclovir was as effective as acyclovir for healing the cutaneous lesion, as indicated by the time to full crusting, loss of acute phase pain, loss of vesicles, and loss of crusts. Famciclovir was well tolerated and had a more favorable adverse event profile compared to acyclovir. Constipation, hematuria, and glycosuria were the most commonly reported adverse events, but only constipation was considered to have a possible relationship to the treatment. In conclusion, famciclovir, administered less frequently and at lower unit doses than acyclovir, is an effective treatment for uncomplicated herpes zoster.

Comparison of the efficacy of lamivudine and famciclovir in Asian patients with chronic hepatitis B: results of 24 weeks of therapy

Lamivudine therapy improves hepatic necro-inflammatory activity, decreases progression of fibrosis, and suppresses hepatitis B virus (HBV) replication. Famciclovir has also been shown to have some effect in the suppression of HBV replication. The aim of the study was to compare the effect of treatment with lamivudine and famciclovir on serum HBV DNA levels in patients with chronic hepatitis B and to assess safety. A prospective randomised clinical study was carried out on 100 patients with chronic hepatitis B infection (50 patients received lamivudine 100 mg daily and 50 patients received famciclovir 500 mg three times a day for 12 weeks. From the twelfth week onwards, patients were offered lamivudine 100 mg daily up to 48 weeks). Significantly more patients treated by lamivudine than by famciclovir had undetectable HBV DNA levels after 12 weeks of therapy (P < 0.001). The median HBV DNA levels were significantly lower in the lamivudine-treated patients from the second week of treatment onwards (P < 0.001 for all time points up to 12 weeks). At week 16, 4 weeks after the famciclovir treated patients were put on lamivudine, there was no longer any difference in HBV DNA levels between the two groups of patients. Both treatments were well tolerated and no serious adverse events were reported. It was concluded that in Chinese patients with chronic hepatitis B infection, lamivudine achieved effective suppression of HBV DNA levels within 4 weeks of therapy whereas famciclovir had a significantly weaker action.

A randomized, double-blind trial of famciclovir versus acyclovir for the treatment of localized dermatomal herpes zoster in immunocompromised patients

In this randomized, double-blind, multicenter, acyclovir-controlled study, the efficacy and safety of famciclovir were evaluated for the treatment of herpes zoster in patients who were immunocompromised following bone marrow or solid organ transplantation or oncology treatment. A total of 148 patients, 12 years or older with clinical evidence of localized herpes zoster, received either oral famciclovir, 500 mg three times daily, or acyclovir, 800 mg five times daily, for 10 days. Famciclovir was equivalent to acyclovir with respect to the numbers of patients reporting new lesion formation while on therapy (77% vs. 73%, respectively). There were no significant differences between the groups in the time to cessation of new lesion formation, full crusting, complete healing of lesions, or loss of acute phase pain. Treatment with famciclovir was well tolerated, with a safety profile comparable to that of acyclovir. Thus oral famciclovir is a convenient, effective, and well-tolerated regimen for immunocompromised patients with herpes zoster.

Famciclovir vs. aciclovir in immunocompetent patients with recurrent genital herpes infections: a parallel-groups, randomized, double-blind clinical trial

BACKGROUND

Twice-daily therapy with famciclovir (FCV) was shown to be effective for episodic therapy for recurrent genital herpes in a large placebo-controlled trial. However, no study has been published to date comparing FCV and aciclovir (ACV).

OBJECTIVES

We have evaluated the effectiveness of FCV vs. ACV in the treatment of recurrent genital herpes infection.

METHODS

A multicentre, double-blind, double-placebo, randomized, parallel-design study, assessed for equivalence, was conducted. As the analysis was based on confidence intervals, a difference of lesion healing time between ACV and FCV (Delta) of 1.05 days with a standard deviation of 2.30 days was chosen. Two hundred and four outpatients were included. Patients self-initiated oral therapy with 125 mg of FCV twice daily or ACV 200 mg five times daily for 5 days. The principal end-point of the study was the complete healing of lesions. Duration of the complete resolution of all symptoms, and safety were also considered.

RESULTS

The mean healing time was 5.1 days and 5.4 days for FCV and ACV, respectively, with a crude value of Delta = 0.25 days (CI 95%: -0.32; 0.82) in the intent-to-treat population. Therefore, the confidence interval for the difference between the two treatments lies entirely within the equivalence range (-1.05-1.05). The value of Delta in the per-protocol population [0.35 day (CI 95%: -0.24; 0.93)] was comparable between the two groups. No differences were detected in the proportion of patients having complete healing at the different days of evaluation as well as in the duration until the complete resolution of all the symptoms. The frequency, nature and severity of adverse events did not differ among the two treatment groups.

CONCLUSIONS

Twice-daily FCV was as effective and safe in the treatment of recurrent genital herpes simplex virus infection as five times daily ACV.

Famciclovir treatment of hepatitis B infection following liver transplantation: a long-term, multi-centre study

Famciclovir is a novel guanosine nucleoside analogue with activity against herpes viruses and hepatitis B virus (HBV). Several preliminary reports have described efficacy of famciclovir in patients with recurrent hepatitis B after orthotopic liver transplantation (OLT). This report describes the largest study to date of long-term famciclovir treatment in patients with de novo or recurrent hepatitis B post-OLT. One hundred thirty patients with detectable serum HBV DNA after OLT received oral famciclovir 500 mg tid on a compassionate-use basis. Safety analyses included all treated patients; efficacy was assessed in all patients and a subgroup of 73 patients with complete baseline HBV DNA and alanine aminotransferase (ALT) data who had received > or =6 months of treatment. Efficacy parameters included serum levels of HBV DNA, ALT, and anti-HBe or anti-HBs seroconversion rates. Of the 70 patients treated for > or =6 months who could be evaluated for response/non-response to famciclovir, 52 (74%) were responders, defined as patients who experienced a 70% decrease or more in HBV DNA levels from baseline, or who became HBV DNA-negative, for at least two consecutive visits. In famciclovir responders, HBV DNA levels decreased by a median of 91% after 12 weeks of treatment, 95% after 6 months and >99% after 18 months of treatment. Marked differentiation between responders and non-responders could be made soon after the onset of treatment. Among anti-HBe positive patients with evidence of HBV replication, 12/13 were responders. Patients with high baseline ALT levels experienced more rapid suppression of HBV DNA during therapy with famciclovir. Famciclovir therapy was safe and well tolerated; serious adverse events were reported infrequently. Famciclovir treatment may be beneficial in patients with hepatitis B infection post-OLT.

[Therapy of recurrent hepatitis B infection after liver transplantation. A retrospective analysis of 200 liver transplantations based on hepatitis B associated liver diseases]

BACKGROUND

Before introduction of passive immunoprophylaxis and new antiviral nucleoside analogues the course of hepatitis B recurrence after liver transplantation could hardly be influenced. The result was a inferior graft survival. In the present retrospective analysis of the efficacy of hepatitis B therapy after liver transplantation was analysed retrospectively.

PATIENTS AND METHODS

Between 1988 and 1998 in total 179 patients were transplanted due to hepatitis B related liver failure at our centre. All patients received passive immunoprophylaxis with hepatitis B immunoglobulin. In case of reinfection after 1993 an antiviral therapy with famciclovir 1500 mg daily was initiated (n = 26), since 1996 lamivudine (100-150 mg daily) was used (n = 12). In case of viral breakthrough under famciclovir treatment or prophylaxis therapy was switched to lamivudine (n = 22). In case of ineffectiveness of lamivudine an antiviral combination therapy with lamivudine and interferon (n = 4) or lamivudine and famciclovir (n = 4) was initiated. Before availability of antiviral agents or in case of viral breakthrough in total 12 patients were retransplanted due to acute or chronic reinfection.

RESULTS

With passive immunoprophylaxis reinfection rate was 33%, 43% and 44% after 1, 3 and 5 years respectively. Without antiviral treatment 52% of patients died within the first year after reinfection. Antiviral therapy with lamivudine or famciclovir improved the one year survival after reinfection to 79%. Suppression of viral replication was more effective with lamivudine. Under lamivudine 26 patients (76%) became HBV-DNA negative, 9 patients HBsAg negative (26%). In contrast no patient became HBsAg negative during famciclovir therapy. Lamivudine was effective also after famciclovir breakthrough in 94% of patients. In case of lamivudine resistant reinfection viral replication could be suppressed with an antiviral combination therapy up to negative HBV-DNA in the hybridization assay. Severe side effects were not observed during any of the antiviral therapies. The graft survival after retransplantation for hepatitis B reinfection was 42% and 25% after one and 3 years.

CONCLUSION

Whereas it is generally accepted, that passive immunoprophylaxis lowers the reinfection rate it could be shown in the present study, that antiviral treatment lowers mortality of hepatitis B reinfection. The major problem of lamivudine and famciclovir is viral resistance formation. In this case an antiviral combination therapy might be useful, whereas retransplantation for hepatitis B reinfection should be considered carefully due to inferior graft survival rates.

Fatal hepatic decompensation in a patient with hepatitis B cirrhosis following famciclovir withdrawal

Hepatitis B virus (HBV) infection is a major cause of chronic liver disease worldwide. Famciclovir is a nucleoside analogue with potent antiviral activity that appears promising in the management of patients with HBV infection. No data exist regarding the safety of nucleoside analogue withdrawal in patients treated for HBV cirrhosis. The authors describe a 41-year-old man with compensated HBV cirrhosis who developed fatal hepatic decompensation due to a rebound in viral replication within six weeks of discontinuing famciclovir therapy. Although several mutations in the HBV DNA polymerase gene have been documented, none has been associated with famciclovir resistance or adverse clinical outcomes. Clinicians should consider the risk of inducing serious flares in hepatic inflammation as a result of abrupt nucleoside analogue withdrawal. Until further data are available regarding the safety of withdrawal of these agents, indefinite treatment may be required in patients with established cirrhosis.

A randomized, placebo-controlled study to evaluate the efficacy of 12-month famciclovir treatment in patients with chronic hepatitis B e antigen-positive hepatitis B

We conducted a randomized, placebo-controlled clinical study evaluating famciclovir (500 mg 3 times daily and 1.5 g once daily) for 1 year (6 months post-treatment follow-up) in patients with chronic hepatitis B e antigen (HBeAg)-positive hepatitis B virus (HBV) infection. The study was conducted in 80 centers in North America, Europe, and Australia/New Zealand. A total of 417 patients with histologically documented chronic hepatitis B (histologic activity index [HAI] 9.5-11.0) received famciclovir (500 mg 3 times daily or 1.5 g once daily) or placebo. Famciclovir 500 mg 3 times daily significantly reduced HBV DNA and median HAI scores versus placebo. By week 8, median HBV DNA decreased from 1,645 to 283 MEq/mL (famciclovir 500 mg 3 times daily) and from 1,147 to 304 MEq/mL (famciclovir 1.5 g once daily), while increasing for placebo (1,617 to 1,685 MEq/mL). Median change in HBV DNA at the end of therapy was -76% (famciclovir 500 mg 3 times daily; P <.01) and -60% (famciclovir 1.5 g once daily; P =.25) versus -37% for placebo. Median change in HAI was -1.5 points (famciclovir 500 mg 3 times daily; P =.02) and -1.0 point (famciclovir 1.5 g once daily; P =.35) and zero for placebo. Fifty percent of patients receiving famciclovir 500 mg 3 times daily (P =.07) and 43% receiving 1.5 g once daily (P =.41) experienced >/=2 points improvement in HAI versus 37% for placebo. Nine percent of patients treated with famciclovir 500 mg 3 times daily underwent anti-HBeAg seroconversion with undetectable HBV DNA at end of follow-up versus 3% in the placebo group (P =.05). Famciclovir was well tolerated; the incidence of post-treatment alanine transaminase (ALT) elevations was comparable with placebo. In conclusion, famciclovir 500 mg 3 times daily gave modest suppression of viral replication, but translated into significant histologic improvement in median HAI score at 1 year.

Efficacy and safety of famciclovir for treating mucocutaneous herpes simplex infection in HIV-infected individuals. Collaborative Famciclovir HIV Study Group

OBJECTIVE

To compare the efficacy and safety of 7 days' treatment with famciclovir 500 mg twice a day versus acyclovir 400 mg five times a day, for mucocutaneous herpes simplex virus (HSV) infection in HIV-infected individuals.

DESIGN

Randomized, double-blind, parallel-group study to demonstrate equivalence for the primary efficacy parameter.

SETTING

Forty-eight hospital-based or specialist public-health clinics in 12 countries.

PATIENTS

Two-hundred and ninety-three HIV-positive patients with recurrent HSV infection (orolabial or genital) starting treatment within 48 h of first appearance of herpetic lesions.

MAIN OUTCOME MEASURES

Proportion of patients developing new lesions during treatment (primary outcome measures); Time to complete healing of lesions, time to cessation of viral shedding, time to loss of lesion-associated symptoms, number of withdrawals due to treatment failure (secondary outcome measures).

RESULTS

Equivalence was defined prospectively and famciclovir was equivalent to acyclovir in preventing new lesion formation: new lesions occurred in 16.7% and 13.3% of patients, respectively [difference, 3.4%; 95% confidence interval (CI), -4.8-11.5]. The groups were comparable in time to complete healing (median 7 days for both groups; hazard ratio, 1.01; 95% CI, 0.79-1.29; P = 0.95), cessation of viral shedding (median of 2 days [hazard ratio = 0.93; 95% C.I. 0.68, 1.27; p = 0.64]), and loss of lesion-associated symptoms (median 4 days; hazard ratio, 0.99; 95% CI, 0.75-1.30; P = 0.93). Similar numbers in each group withdrew because of treatment failure. There were no differences between groups in the incidence of adverse events.

CONCLUSIONS

Famciclovir given twice a day is as effective and well tolerated as high-dose acyclovir for mucocutaneous HSV infections in HIV-infected individuals, and has the convenience of less frequent dosing.

Famciclovir in chronic hepatitis B: results of a dose-finding study

BACKGROUND/AIMS

Famciclovir, an orally available nucleoside analogue with potent in vitro activity against HBV, is being investigated for treatment of chronic hepatitis B.

METHODS

A dose-finding study was conducted in patients with hepatitis B e antigen present in serum. Patients received famciclovir 125 mg, 250 mg, 500 mg three times daily (tid) or placebo for 16 weeks, followed by 8 months post-treatment observation, and 16 weeks open-label treatment. More than 90% of patients had previously received alpha-interferon or had baseline characteristics indicating a high likelihood of poor response to alpha-interferon.

RESULTS

Famciclovir induced rapid, dose-dependent suppression of viral replication and reduction in alanine aminotransferase (ALT), with greatest efficacy in the 500-mg tid treatment group. HBV DNA reduction was maintained throughout the treatment period. ALT also steadily declined during the treatment period. Approximately 40% of patients with pretreatment ALT>upper limit of normal (ULN) receiving famciclovir 500 mg tid, experienced sustained normalization of ALT at the end of the 8-month follow-up. Anti-HBe seroconversion occurred more frequently in patients receiving famciclovir 500 mg tid compared with placebo (p=0.04). Famciclovir was generally well tolerated; the incidence of adverse events was comparable to placebo. Exacerbation of liver disease or serious ALT flares were not observed.

CONCLUSION

Famciclovir 500 mg three times daily may offer an alternative to alpha-interferon for treatment for chronic hepatitis B. Anti-HBe seroconversion in the famciclovir 500-mg tid group suggests that 16 weeks treatment has the potential for HBV clearance. Further studies with a longer treatment duration are warranted.

Combination treatment with famciclovir and a topical corticosteroid gel versus famciclovir alone for experimental ultraviolet radiation-induced herpes simplex labialis: a pilot study

To investigate the efficacy of corticosteroids for the treatment of herpes labialis, we compared famciclovir (Famvir, 500 mg 3x/day po [per os] for 5 days) and topical fluocinonide (0.05% Lidex Gel 3x/day for 5 days) with famciclovir and topical vehicle control for experimental ultraviolet radiation-induced herpetic recurrences. We irradiated 49 volunteers, and 29 (60%) of 48 developed signs or symptoms of a recurrence. They self-initiated treatment, and we were able to evaluate them. There was a trend in the combination group toward more aborted lesions, compared with those who received antiviral therapy alone (7 [41%] of 17 vs. 1 [8%] of 12; P=.09). Combination therapy significantly reduced the median maximum lesion size (48 vs. 162 mm(2); P=.02) and the number of patients who experienced lesion pain (10 [59%] of 17 vs. 12 [100%] of 12; P=.02). Adverse events were minimal. Corticosteroids in combination with an antiviral agent may be safe and beneficial for episodic treatment of herpes labialis. Larger studies are needed to confirm these findings.

Famciclovir update. Chronic hepatitis B

The growing body of preclinical data, as well as clinical data from the phase II doseranging study in immunocompetent patients and from liver transplant recipients participating in the compassionate use program, indicates that famciclovir offers the promise of safe and convenient oral treatment of chronic hepatitis B infection. The results of phase III pivotal studies are eagerly awaited. Denavir is a trademark of SmithKline Beecham plc.

Peroral famciclovir in the treatment of experimental ultraviolet radiation-induced herpes simplex labialis: A double-blind, dose-ranging, placebo-controlled, multicenter trial

Three doses of famciclovir were tested for treatment of experimental ultraviolet radiation (UVR)-induced herpes labialis. Patients received 125, 250, or 500 mg of famciclovir or placebo 3 times a day for 5 days beginning 48 h after UVR exposure, a model of early episodic intervention. Of 248 patients irradiated, 102 developed lesions while on treatment. There were no significant differences between groups in the number of lesions. The mean maximal lesion size was reduced in a dose-proportional manner: 139, 105, 77, and 55 mm2 for the placebo and 125-, 250-, and 500-mg famciclovir groups, respectively (P=.040, linear regression). Median time to healing was faster in the 500-mg famciclovir group than in the placebo group, both by investigator (4 vs. 6 days, 33% reduction, P=.010) and patient assessment (3.0 vs. 5.8 days, 48% reduction, P=.008) analyses. These findings suggest that evaluation of higher drug doses for herpes labialis treatment is warranted.

Oral famciclovir for the suppression of recurrent genital herpes: a randomized controlled trial. Collaborative Famciclovir Genital Herpes Research Group

CONTEXT

Recurrent genital herpes simplex virus (HSV) may be treated episodically, but this may not be sufficient for patients with frequent recurrences.

OBJECTIVE

To determine the efficacy and safety of famciclovir in the suppression of recurrent genital HSV infection.

DESIGN

A randomized, double-blind, placebo-controlled, parallel-group study.

SETTING

Thirty university, hospital, or private outpatient referral centers in Canada and Europe.

PATIENTS

A total of 455 patients (223 men, 232 women) aged 18 years or older with a history of 6 or more episodes of genital herpes during 12 of the most recent 24 months, in the absence of suppressive therapy, received study medication.

INTERVENTION

Oral famciclovir, 125 mg or 250 mg 3 times daily or 250 mg twice daily, or placebo for 52 weeks.

MAIN OUTCOME MEASURES

Time to the first recurrence of genital HSV infection; the proportion of patients remaining free of HSV recurrence at 6 months; frequency of adverse events.

RESULTS

In an intent-to-treat analysis, famciclovir significantly delayed the time to the first recurrence of genital herpes at all dose regimens (hazard ratios, 2.9-3.3; P<.001); median time to recurrence for famciclovir recipients was 222 to 336 days compared with 47 days for placebo recipients. The proportion of patients remaining free of HSV recurrence was approximately 3 times higher in famciclovir recipients (79%-86%) than in placebo recipients (27%) at 6 months (relative risks, 2.9-3.1; P<.001); efficacy was maintained at 12 months. Famciclovir was well tolerated with an adverse experience profile comparable to placebo.

CONCLUSIONS

Oral famciclovir (125 mg or 250 mg 3 times daily or 250 mg twice daily) is an effective, well-tolerated treatment for the suppression of genital HSV infection in patients with frequent recurrences.

Slightly helpful in herpes zoster

A comparative placebo-controlled trial involving 419 adults showed that a one-week course of famciclovir started within 3 days of onset of skin lesions had no effect on the acute phase of zoster, the time required for scabs to fall, the end of skin lesion progression, or pain. In this trial famciclovir failed to reduce the incidence of post-zoster pain, but it did reduce its median duration by approximately 2 months. According to a subgroup analysis (not planned for by the protocol), only patients over 50 benefited from this effect. Three other trials suggest that the approved dose regimen in France (500 mg 3 times a day) may not be optimal. The dose recommended in the United Kingdom (750 mg in one daily intake or 250 mg 3 times a day) seems to be more in line with the clinical assessment file. The three available comparative trials show no statistically significant difference between famciclovir and aciclovir in terms of efficacy or tolerability. An indirect comparison suggests that the risk-benefit ratio of famciclovir and valaciclovir are probably similar. However, the effects of famciclovir on post-zoster pain were observed in a clinical trial, while those of aciclovir were found only in meta-analyses.

A review of famciclovir in the management of genital herpes

The frequent occurrence of genital herpes continues to be a serious clinical problem. Although not life threatening, the physical symptoms of the disease, and the ensuing psychosocial complications, can be overwhelming to patients. The life cycle of the herpes simplex virus is complex, comprising multiple stages. Following infection, the virus establishes life-long latency in its host and can reactivate at any time as a recurrent infection. Successful management of genital herpes simplex infections involves patient education and psychological support, as well as antiviral agents. The antiviral agent famciclovir has been shown to shorten the course and decrease the severity of episodes of recurrent genital herpes. In addition, famciclovir has been shown to be effective in suppressing recurrent genital herpes. A review of the clinical experience with famciclovir in the treatment of genital herpes is presented.

A review of famciclovir in the management of genital herpes

The frequent occurrence of genital herpes continues to be a serious clinical problem. Although not life threatening, the physical symptoms of the disease, and the ensuing psychosocial complications, can be overwhelming to patients. The life cycle of the herpes simplex virus is complex, comprising multiple stages. Following infection, the virus establishes life-long latency in its host and can reactivate at any time as a recurrent infection. Successful management of genital herpes simplex infections involves patient education and psychological support, as well as antiviral agents. The antiviral agent famciclovir has been shown to shorten the course and decrease the severity of episodes of recurrent genital herpes. In addition, famciclovir has been shown to be effective in suppressing recurrent genital herpes. A review of the clinical experience with famciclovir in the treatment of genital herpes is presented.

Pretransplant famciclovir as prophylaxis for hepatitis B virus recurrence after liver transplantation

Liver transplantation in patients with detectable hepatitis B virus (HBV) DNA is associated with a high rate of HBV recurrence and detectable HBV DNA is often considered a contraindication for liver transplantation. Famciclovir, an oral form of the purine nucleoside penciclovir, has been shown to inhibit HBV replication. This pilot study was conducted to determine whether a 6-month course of famciclovir, administered before transplantation, was effective in inhibiting HBV replication in patients with end-stage liver disease caused by HBV and detectable HBV DNA and to assess the posttransplant clinical and virologic outcome of patients becoming HBV DNA negative with famciclovir prior to transplantation. All eight patients enrolled were hepatitis B surface antigen (HBsAg) positive; their HBV DNA levels at baseline ranged from 4.3 to 25,321 pg/ml (mean 3,661 pg/ml). Six of the eight patients were also seropositive for HBeAg. An initial decline in HBV DNA titers occurred in all patients; however, only 25% (two of eight) of the patients became HBV DNA negative before transplantation and underwent liver transplantation. Seroconversion to hepatitis B surface antibody (HBsAb) (and HBeAb in HBeAg-positive patient) was demonstrated at the conclusion of famciclovir in the transplanted patients. Both patients remain HBV DNA negative at nearly 2 years of follow-up after transplantation. HBV DNA remained detectable in 63% (five of eight) of the patients. The mean HBV DNA level for patients who became HBV DNA negative was 5.1 pg/ml versus 424 pg/ml in nonresponders. Adverse effects attributable to famciclovir were not observed in any of the patients. Future studies should assess the predictors of response to famciclovir so that patients likely to achieve good virologic outcome can be targeted for such a therapy.

Oral famciclovir for suppression of recurrent genital herpes simplex virus infection in women. A multicenter, double-blind, placebo-controlled trial. Collaborative Famciclovir Genital Herpes Research Group

OBJECTIVE

To evaluate the efficacy and safety of oral famciclovir in the suppression of genital herpes.

METHODS

In this randomized, double-blind, placebo-controlled trial that was performed at 11 university and 9 private ambulatory care referral centers, 375 women who were 18 years of age or older and had a history of 6 or more episodes of genital herpes during 12 of the last 24 months in the absence of suppressive therapy were treated for 4 months with oral famciclovir, 125 mg once daily or twice daily, 250 mg once daily or twice daily, 500 mg once daily, or placebo. The primary outcome measures included the time to first clinically and virologically confirmed recurrences, and safety as measured by clinical laboratory tests and adverse experiences.

RESULTS

The median time to first recurrence was 82 days in the placebo group, 114 days in those receiving famciclovir, 125 mg once daily, and more than 120 days in the other treatment groups. When compared with placebo recipients, the time to the first clinical recurrence was significantly prolonged in subjects who received famciclovir, 125 mg twice daily (hazard ratio, 1.8; 95% confidence interval, 1.0-3.0; P = .03), and in those who received famciclovir, 250 mg twice daily (hazard ratio, 3.6; 95% confidence interval, 1.9-6.9; P < .001). Treatment was well tolerated, and there was no evidence of emergence of resistance during or after suppressive famciclovir therapy.

CONCLUSIONS

Oral famciclovir, 250 mg, given twice daily for 4 months is an effective, well-tolerated treatment for the suppression of genital herpes in women with frequent recurrences, but single daily doses produced less complete suppression of genital herpes.

Patient-initiated, twice-daily oral famciclovir for early recurrent genital herpes. A randomized, double-blind multicenter trial. Canadian Famciclovir Study Group

OBJECTIVE

To compare the efficacy and safety of episodic patient-initiated oral famciclovir with placebo in recurrent genital herpes.

DESIGN

Randomized, double-blind, frequent-observation, dose-ranging study comparing twice-daily 125-mg, 250-mg, or 500-mg oral famciclovir with placebo. Patients initiated therapy after self-culturing, reported to the clinic within 12 hours, and were assessed twice daily for at least 5 days.

SETTING

Fifteen Canadian university, private practice, or public outpatient clinics.

PATIENTS

A total of 692 patients with culture-proven recurrent genital herpes were randomized; 467 patients experienced a symptomatic episode and commenced treatment.

MAIN OUTCOME MEASURE

Time to complete healing of all lesions.

RESULTS

Famciclovir (all doses) was significantly more effective than placebo in reducing time to healing, time to cessation of viral shedding, and durations of lesion edema, vesicles, ulcers, and crusts. Times to cessation of all symptoms and of moderate to severe lesion tenderness, pain, and burning were also reduced. Patients who initiated famciclovir prior to viral shedding were more likely to not shed virus throughout. All doses were equally effective, safe, and well tolerated.

CONCLUSIONS

Oral famciclovir reduced the onset and duration of viral shedding, lesion persistence, and uncomfortable symptoms. Several individual symptoms and lesion stages were also reduced in duration by this episodic therapy. Additionally, our twice-daily observation trial design proved to be a helpful tool for studying recurrent disease. Episodic oral famciclovir provides a convenient and effective alternative for those patients with recurrent genital herpes whose frequency rates do not require continuous antiviral suppression.

Famciclovir: review of clinical efficacy and safety

Famciclovir is the well-absorbed oral form of penciclovir, an antiviral agent with potent activity against varicella-zoster virus (VZV) and herpes simplex virus (HSV-1) and 2 (HSV-2). After oral administration, famciclovir is rapidly converted to penciclovir with a bioavailability of 77%. penciclovir is efficiently phosphorylated to the active metabolite, penciclovir-triphosphate, and has a prolonged intracellular half-life of approximately 9-10 h in VZV-infected cells, and 10 and 20 h in cells infected with HSV-1 and HSV-2, respectively. Two multicenter clinical trials have shown that famciclovir given during the acute zoster phase accelerated healing of cutaneous lesions. More importantly, in a placebo-controlled study, famciclovir reduced the duration of postherpetic neuralgia (PHN), particularly in elderly patients. Famciclovir has also been proven effective in treating recurrent genital herpes, as demonstrated by a reduction in times to cessation of viral shedding, complete healing, and loss of all symptoms. One study showed that suppressive therapy with famciclovir was effective in reducing genital herpes episodes in patients with frequent recurrences. A promising new area of investigation for famciclovir is controlling virus replication in patients with chronic hepatitis B virus (HBV) or HBV reinfections after liver transplant. Results from a double-blind, placebo-controlled, pilot study and several case reports have shown that famciclovir, alone or in combination with other agents, decreased HBV-DNA levels and was tolerated with long-term treatment. Available clinical data indicate that famciclovir is an effective agent for treating herpes and holds significant promise for the treatment of chronic HBV infection HBV reinfection after liver transplantation.

Famciclovir for the treatment of acute herpes zoster: effects on acute disease and postherpetic neuralgia. A randomized, double-blind, placebo-controlled trial. Collaborative Famciclovir Herpes Zoster Study Group

OBJECTIVE

To document the effects of treatment with famciclovir on the acute signs and symptoms of herpes zoster and postherpetic neuralgia.

DESIGN

A randomized, double-blind, placebo-controlled, multicenter trial.

SETTING

36 centers in the United States, Canada, and Australia.

PATIENTS

419 immunocompetent adults with uncomplicated herpes zoster.

INTERVENTION

Patients were assigned within 72 hours of rash onset to famciclovir, 500 mg; famciclovir, 750 mg; or placebo, three times daily for 7 days.

MEASUREMENTS

Lesions were assessed daily for as long as 14 days until full crusting occurred and then weekly until the lesions healed. Viral cultures were obtained daily while vesicles were present. Pain was assessed at each of the visits at which lesions were examined and then monthly for 5 months after the lesions healed. Safety was assessed throughout the study.

RESULTS

Famciclovir was well tolerated, with a safety profile similar to that of placebo. Famciclovir accelerated lesion healing and reduced the duration of viral shedding. Most importantly, famciclovir recipients had faster resolution of postherpetic neuralgia (approximately twofold faster) than placebo recipients; differences between the placebo group and both the 500-mg famciclovir group (hazard ratio, 1.7 [95% CI, 1.1 to 2.7]) and the 750-mg famciclovir group (hazard ratio, 1.9 [CI, 1.2 to 2.9]) were statistically significant (P = 0.02 and 0.01, respectively). The median duration of postherpetic neuralgia was reduced by approximately 2 months.

CONCLUSIONS

Oral famciclovir, 500 mg or 750 mg three times daily for 7 days, is an effective and well-tolerated therapy for herpes zoster that decreases the duration of the disease's most debilitating complication, postherpetic neuralgia.

Safety of famciclovir in patients with herpes zoster and genital herpes

Safety reporting from individual ongoing and completed clinical studies has demonstrated that famciclovir, the well-absorbed oral form of the antiherpesvirus agent penciclovir, has been well tolerated by more than 3,000 individuals worldwide. An integrated safety evaluation has been performed and includes over 1,600 patients from 11 completed, randomized, double-blind clinical trials and 2 open trials. The famciclovir population consisted of 816 herpes zoster patients (four trials), 409 patients with acute genital herpesvirus infections (seven trials), and 382 patients from two genital herpes suppression studies. Overall, the famciclovir-treated patient population was 57.7% female and ranged in age from 15 to 102 years (mean, 42.6 years), with 31.2% aged 50 years or more and 15.7% aged 65 years or more. The mean duration of exposure to famciclovir was 28.8 days (5.8 days excluding suppression studies). The total daily doses ranged from 125 mg to 2.25 g. The most common adverse experiences reported as related to study medication (famciclovir and placebo) were headache, nausea, and diarrhea. The frequencies of adverse experiences and laboratory abnormalities (hematology, clinical chemistry, and urinalysis parameters) were similar in both famciclovir and placebo recipients. Thus, safety data from the analysis of 13 completed clinical studies demonstrate that famciclovir is tolerated well by patients with either herpes zoster or genital and has a safety profile comparable to that of placebo.

Linear pharmacokinetics of penciclovir following administration of single oral doses of famciclovir 125, 250, 500 and 750 mg to healthy volunteers

Twenty healthy male volunteers received single oral doses of famciclovir (125-750 mg), in a randomized, single-blind, crossover study. Plasma and urine concentrations of penciclovir and its 6-deoxy precursor, BRL 42359, were determined and penciclovir plasma concentration-time data submitted to model-independent pharmacokinetic analysis. Peak plasma concentrations of penciclovir were obtained at median times of 0.5-0.75 h after dosing. The areas under the concentration versus time curves (AUC) and the peak penciclovir concentration (Cmax) increased linearly with dose of famciclovir. Time to Cmax, elimination half-life, urinary recovery and renal clearance of penciclovir did not change with increasing dose. Famciclovir was excreted via the kidneys as penciclovir (60%) and BRL 42359 (5%), respectively. Famciclovir was well tolerated by all subjects with a low incidence of adverse effects. In conclusion, penciclovir thus displays linear pharmacokinetics in the anticipated therapeutic dose range of famciclovir.