Therapy of genital herpes with topically applied interferon

Off-label uses of biologics in dermatology: Interferon and intravenous immunoglobulin (Part 1 of 2)

The introduction of a number of biologic therapies into the market has revolutionized the practice of dermatology. These therapies include interferons, intravenous immunoglobulin, infliximab, adalimumab, etanercept, efalizumab, alefacept, and rituximab. Most dermatologists are familiar with the Food and Drug Administration-approved indications of these medications. However, numerous off-label uses have evolved. As part 1 of a 2-part series, this article will review the literature regarding the off-label uses of the interferons and intravenous immunoglobulin in dermatology.

In vitro susceptibility of 10 clinical isolates of SARS coronavirus to selected antiviral compounds

Effective antiviral agents are urgently needed to combat the possible return of severe acute respiratory syndrome (SARS). Commercial antiviral agents and pure chemical compounds extracted from traditional Chinese medicinal herbs were screened against 10 clinical isolates of SARS coronavirus by neutralisation tests with confirmation by plaque reduction assays. Interferon-beta-1a, leukocytic interferon-alpha, ribavirin, lopinavir, rimantadine, baicalin and glycyrrhizin showed antiviral activity. The two interferons were only active if the cell lines were pre-incubated with the drugs 16 h before viral inoculation. Results were confirmed by plaque reduction assays. Antiviral activity varied with the use of different cell lines. Checkerboard assays for synergy were performed showing combinations of interferon beta-1a or leukocytic interferon-alpha with ribavirin are synergistic. Since the clinical and toxicity profiles of these agents are well known, they should be considered either singly or in combination for prophylaxis or treatment of SARS in randomised placebo controlled trials in future epidemics.

Medical treatment of viral pneumonia including SARS in immunocompetent adult

Since no randomized controlled trials have been conducted on the treatment of viral pneumonia by antivirals or immunomodulators in immunocompetent adults, a review of such anecdotal experience are needed for the more rational use of such agents. Case reports (single or case series) with details on their treatment and outcome in the English literature can be reviewed for pneumonia caused by human or avian influenza A virus (50 patients), varicella zoster virus (120), adenovirus (29), hantavirus (100) and SARS coronavirus (SARS-CoV) (841). Even with steroid therapy alone, the mortality rate appeared to be lower when compared with conservative treatment for pneumonia caused by human influenza virus (12.5% vs. 42.1%) and hantavirus (13.3% vs. 63.4%). Combination of an effective antiviral, acyclovir, with steroid in the treatment of varicella zoster virus may be associated with a lower mortality than acyclovir alone (0% vs. 10.3%). Combination of interferon alfacon-1 plus steroid, or lopinavir/ritonavir, ribavirin plus steroid were associated with a better outcome than ribavirin plus steroid (0% vs. 2.3% vs. 7.7%, respectively). Combination of lopinavir/ritonavir plus ribavirin significantly reduced the virus load of SARS-CoV in nasopharyngeal, serum, stool and urine specimens taken between day 10 and 15 after symptom onset when compared with the historical control group treated with ribavirin. It appears that the combination of an effective antiviral and steroid was associated with a better outcome. Randomized therapeutic trial should be conducted to ascertain the relative usefulness of antiviral alone or in combination with steroid.

Keratins and the keratinocyte activation cycle

In wound healing and many pathologic conditions, keratinocytes become activated: they turn into migratory, hyperproliferative cells that produce and secrete extracellular matrix components and signaling polypeptides. At the same time, their cytoskeleton is also altered by the production of specific keratin proteins. These changes are orchestrated by growth factors, chemokines, and cytokines produced by keratinocytes and other cutaneous cell types. The responding intracellular signaling pathways activate transcription factors that regulate expression of keratin genes. Analysis of these processes led us to propose the existence of a keratinocyte activation cycle, in which the cells first become activated by the release of IL-1. Subsequently, they maintain the activated state by autocrine production of proinflammatory and proliferative signals. Keratins K6 and K16 are markers of the active state. Signals from the lymphocytes, in the form of Interferon-gamma, induce the expression of K17 and make keratinocytes contractile. This enables the keratinocytes to shrink the provisional fibronectin-rich basement membrane. Signals from the fibroblasts, in the form of TGF-beta, induce the expression of K5 and K14, revert the keratinocytes to the healthy basal phenotype, and thus complete the activation cycle.

Current recommendations for the treatment of genital herpes

The incidence of genital herpes continues to increase in epidemic-like fashion. Aciclovir (acyclovir) has been the original gold standard of therapy. The recent addition of famciclovir and valaciclovir as antiherpes drugs has improved convenience as well as the efficacy of treatment. Although aciclovir remains a widely prescribed and reliable drug, its administration schedule falls short of the ease of usage that the newer nucleoside analogues offer, for both episodic and suppressive therapy. Suppression of symptomatic disease and asymptomatic shedding from the genitalia have both become popular approaches, if not the primary targets of antiviral therapy. Knowing that asymptomatic disease leads to most cases of transmission strongly suggests that suppression with antiviral agents could reduce transmission risk in discordant couples. Unfortunately, the role for antivirals in reducing transmission remains to be proven in clinical trials. Neonatal herpes is now successfully treated using aciclovir. Current randomised clinical trials are examining aciclovir and valaciclovir administration, as well as safety and efficacy for post-acute suppressive therapy. Prevention of recurrences in pregnancy is also a topic under investigation, with a view to reducing the medical need for Cesarean section, or alternatively (and far less likely to be accomplished) to protect the neonate. Although resistance is largely limited to the immunocompromised and a change in resistance patterns is not expected, several drugs are available for the treatment of aciclovir-resistant strains of herpes simplex. Foscarnet is the main alternative with proven efficacy in this setting. Unfortunately, administration of foscarnet requires intravenous therapy, although a single anecdote of topical foscarnet efficacy in this setting has been published. Alternatives include cidofovir gel, which is not commercially available but can be formulated locally from the intravenous preparation. Less effective alternatives include trifluridine and interferon. Future possibilities for treatment of genital herpes include a microparticle-based controlled-release formulation of aciclovir and resiquimod (VML-600; R-848). The search for an effective therapeutic vaccine for genital herpes has not been successful to date, although a live virus glycoprotein H-deficient (DISC) vaccine is currently in clinical trials. Recent data suggest that seronegative women are protected (albeit, not fully) by a glycoprotein D recombinant vaccine with adjuvant. Despite the established safety and convenience of current treatment options, better suppressive options and topical treatment options are much needed. Studies using existing agents as potential tools to avoid Cesarean section, or transmission to neonate or partner are ongoing. Both vaccines and antivirals may eventually play a role in prevention of infection.

Epidermal signal transduction and transcription factor activation in activated keratinocytes

In the area of biology, many laboratories around the world are dissecting and characterizing signal transduction mechanisms and transcription factors responsive to various growth factors and cytokines, in various cell types. However, because of the differences in systems used, it is not clear whether these systems coexist, whether they interact meaningfully, and what their relative roles are. Epidermal keratinocytes are the perfect cell type in which to integrate this knowledge, because in these cells these mechanisms are known to be relevant. Keratinocytes both produce and respond to growth factors and cytokines, especially in pathological conditions and during wound healing, when the physiology of keratinocytes is altered in a way specified by the presence of a subset growth factors and cytokines. In fact, growth factors and cytokines cause the major changes in gene expression and keratinocyte behavior in various cutaneous diseases. In some cases, such as in wound healing, these responses are highly beneficial; in others, such as in psoriasis, they are pathological. It is not clear at present which are operating in which conditions, which are important for the healing process and which are harmful. Growth factors and cytokines affect keratinocytes sometimes simultaneously, at other times individually. In this manuscript we describe the signal transduction pathways responsible for the effects of interferons, the EGF/TGF alpha family and the TNF alpha/IL-1 family of signaling molecules. We also describe the important transcription factors known to be functional in epidermis, with particular emphasis on those factors that are activated by growth factors and cytokines. Finally, we describe what is known about transcriptional regulation of keratin genes, especially those specifically expressed in pathological processes in the epidermis. We expect that the enhanced understanding of the pathways regulating gene expression in keratinocytes will identify the pharmacological targets, the signal transducing proteins and the corresponding transcription factors, used by growth factors and cytokines. This research will led to development of compounds precisely aimed at those targets, allowing us to isolate and inhibit the harmful side effects of growth factors and cytokines. Such compounds should lead to highly specific and therefore more effective treatments of the cutaneous disorders in which these pathways play significant roles.

Effect of topical interferon-beta on recurrence rates in genital herpes: a double-blind, placebo-controlled, randomized study

The aim of this randomized, double-blind placebo-controlled trial was to evaluate the effect of IFN-beta cream applied at the time of recurrent eruptions of genital herpes during 6 months on the overall rate of recurrence. Therapy was initiated at the clinic for the first treated recurrence, and thereafter by the patient for early treatment of eventual subsequent eruptions. Each recurrence was ascertained at the clinic in all 35 evaluable patients. The mean recurrence rate was significantly lower in the group using IFN-beta cream than in the placebo group (p = 0.03). Complete responders without recurrence for the duration of the trial were 36.4% of all patients and 46% among women versus 15.4 and 16.6% in the placebo groups, respectively. A total of 77.3% of all patients were defined as complete or partial responders, their average recurrences/year decreasing from 11 to 2.2 (p < 0.0001). The topical episodic IFN-beta treatment was well tolerated by patients and without side effects. It is concluded that IFN-beta cream application reduces the overall rate of recurrence of genital herpes.

Recombinant alpha-2 interferon gel treatment of recurrent herpes genitalis

Topical recombinant alpha-2 interferon treatment of recurrent genital herpes was studied in a randomized, double-blind, placebo controlled clinical trial. Three hundred and eighty-seven patients were treated at eight study centers with either interferon gel or placebo four times daily for four days. Interferon therapy caused a 26% decrease in the duration of viral shedding. For male patients, there were also significant decreases in the time to crusting (17%) and duration of pain (34%) and itching (21%). For patients with recurrent genital herpes, treatment with topical interferon was found to be effective in decreasing the duration of viral shedding and, for males, pain, itching and time to crusting.

Topical delivery of liposomally encapsulated interferon evaluated by in vitro diffusion studies

The topical delivery of several liposomal interferon formulations was evaluated by in vitro diffusion experiments in an effort to understand the effects of liposomal composition and method of preparation on the deposition of interferon into the stratum corneum and deeper strata of the skin. Application of liposomes prepared from lipids with a composition similar to that of the stratum corneum resulted in almost twice the amount of interferon being deposited in the deeper skin layers than did application of liposomes prepared from phospholipids. Topical application of "skin lipid" liposomes prepared by the dehydration-rehydration method was twice as effective as was topical application of liposomes prepared by the reverse-phase evaporation method with respect to their ability to deposit interferon into the skin strata where the basal cell layers reside. These results are consistent with the effects of liposomal composition and method of preparation on the ability of the formulation to reduce lesion scores in the cutaneous herpes simplex virus type 1 guinea pig model.

Effects of the immunomodulating agent R837 on acute and latent herpes simplex virus type 2 infections

R837 is an immune modulator with no in vitro activity against herpes simplex virus (HSV). We evaluated topical R837 as therapy for genital HSV type 2 infection using the guinea pig model of this disease. Furthermore, we investigated the effect of R837 therapy on acute and latent neural HSV infections. Therapy initiated 12 h after viral inoculation and given twice a day significantly reduced the acute neural infection so that HSV was recovered from only 1 of 64 neural tissue specimens obtained from R837 recipients compared with 43 of 56 specimens obtained from placebo recipients (P less than 0.0001). R837 initiated 36 h after HSV inoculation and given once a day also significantly reduced the total mean lesion score of the acute disease from 14.1 +/- 4.3 to 2.6 +/- 5.3 (P less than 0.0001) and shortened the period of vaginal HSV shedding from 6.9 +/- 1.7 to 3.2 +/- 1.4 days (P less than 0.001). R837-treated animals also developed fewer HSV recurrences than did controls (2.0 +/- 1.7 versus 5.1 +/- 1.7; P less than 0.0002). Latent HSV was detected in 23 of 24 dorsal root ganglia explant cultures from placebo recipients but in only 2 of 30 cultures from R837-treated animals, and HSV in these 2 cultures was detectable only with the addition of a demethylating agent. Topical R837 exhibited in vivo anti-HSV activity, reducing both acute and latent neural infections as well as acute and recurrent genital disease.

Topical delivery of liposomally encapsulated interferon evaluated in a cutaneous herpes guinea pig model

The topical delivery of liposomally encapsulated interferon was evaluated in the cutaneous herpes simplex virus guinea pig model. Application of liposomally entrapped interferon caused a reduction of lesion scores, whereas application of interferon formulated as a solution or as an emulsion was ineffective. The method of liposomal preparation rather than the lipid composition of the bilayers appeared to be the most important factor for reducing lesion scores. Only liposomes prepared by the dehydration-rehydration method were effective. This finding implied that the dehydration and subsequent rehydration of the liposomes facilitate partitioning of the interferon into liposomal bilayers, where the drug is positioned for transfer into the lipid compartment of the stratum corneum. Liposomes do not appear to function as permeation enhancers but seem to provide the needed physicochemical environment for transfer of interferon into the skin.

Promising new antiviral drugs

We now have a basis for a more rational approach to rapid evaluation and development of antiviral drugs by screening for activity in vitro, testing for toxicity and efficacy in animals, and clinical testing in humans. Acyclovir is a prototype of this improved process. Interferon has a beneficial effect against CMV infection in renal transplant patients and has promising results in the treatment of papillomas and rhinovirus infections. It does not seem to be as effective against genital herpes or varicella zoster as acyclovir. Ribavirin is effective against respiratory syncytial virus infections and Lassa fever. Varicella-zoster virus is highly sensitive to bromovinyl deoxyuridine in vitro. Phosphonoformate is effective in herpes simplex in animals but of little clinical benefit topically in human recurrent A2 herpes. Zidovudine may decrease mortality rates and infectious complications in patients with acquired immunodeficiency syndrome. DHPG (9-(1,3-dihydroxy-2-propoxymethyl]guanine is useful in treatment of cytomegalovirus and infection in immunocompromised patients. The prodrug of acyclovir results in high blood levels of acyclovir and shows promise in the treatment of varicella-zoster infections. Many halogenated pyrimidine nucleoside analogs are being developed. Buciclovir is another acyclic guanosine analog effective against herpes simplex virus in vitro. 2'-nor-cyclic guanosine monophosphate has a broad antiviral spectrum of action. Interleukin-2 is being investigated. Combined therapies of two or more antiviral drugs or antiviral drugs and other treatments are being studied.