Herpes zoster (shingles) and postherpetic neuralgia

Reducing the burden of Herpes Zoster in Italy

Herpes Zoster (HZ) is a viral disease with painful neuro-dermatologic manifestations. Incidence increases with age. In Italy, the estimated incidence is 6.3 cases/1000 person/year; hospital admissions are less than 2%, 69% in patients aged over 65 years. The most frequent complication of HZ is Post-Herpetic Neuralgia (PHN) characterized by metameric pain, allodynia, and hyperalgesia. In Italy 20.6% and 9.2% of HZ patients experience PHN after 3 and 6 months, respectively. Available antiviral and analgesic treatments are relatively unsatisfactory in reducing pain and length of the disease. Prevention has recently become possible with the live attenuated vaccine Oka/Merck. Clinical studies show a reduction of 51% in the incidence of the disease, 61% of its burden and 67% of PHN in vaccinees. Protection seems to be long lasting and vaccine safety matches registration requirements. Available evidence suggests that the costs for QALY (less than € 20 000) and avoided cases is favorable. Due to the heavy burden of disease, it is time to offer this vaccination to elderly population.

β-l-1-[5-(E-2-bromovinyl)-2-(hydroxymethyl)-1,3-(dioxolan-4-yl)] uracil (l-BHDU) prevents varicella-zoster virus replication in a SCID-Hu mouse model and does not interfere with 5-fluorouracil catabolism

The alphaherpesvirus varicella-zoster virus (VZV) causes chickenpox and shingles. Current treatments are acyclovir (ACV) and its derivatives, foscarnet and brivudine (BVdU). Additional antiviral compounds with increased potency and specificity are needed to treat VZV, especially to treat post-herpetic neuralgia. We evaluated β-l-1-[5-(E-2-bromovinyl)-2-(hydroxymethyl)-1,3-(dioxolan-4-yl)] uracil (l-BHDU, 1) and 5'-O-valyl-l-BHDU (2) in three models of VZV replication: primary human foreskin fibroblasts (HFFs), skin organ culture (SOC) and in SCID-Hu mice with skin xenografts. The efficacy of l-BHDU in vivo and its drug-drug interactions were previously not known. In HFFs, 200μM l-BHDU was noncytotoxic over 3days, and l-BHDU treatment reduced VZV genome copy number and cell to cell spread. The EC50 in HFFs for l-BHDU and valyl-l-BHDU were 0.22 and 0.03μM, respectively. However, l-BHDU antagonized the activity of ACV, BVdU and foscarnet in cultured cells. Given its similar structure to BVdU, we asked if l-BHDU, like BVdU, inhibits 5-fluorouracil catabolism. BALB/c mice were treated with 5-FU alone or in combination with l-BHDU or BVdU. l-BHDU did not interfere with 5-FU catabolism. In SCID-Hu mice implanted with human skin xenografts, l-BHDU and valyl-l-BHDU were superior to ACV and valacyclovir. The maximum concentration (Cmax) levels of l-BHDU were determined in mouse and human tissues at 2h after dosing, and comparison of concentration ratios of tissue to plasma indicated saturation of uptake at the highest dose. For the first time, an l-nucleoside analog, l-BHDU, was found to be effective and well tolerated in mice.

Streptomycin-lidocaine injections for the treatment of postherpetic neuralgia: Report of three cases with literature review

The sudden, stabbing, paroxysmal pain of neuralgia is the fiercest agony that a patient may experience in his life. Many varied medical treatments and surgical procedures have been suggested in the literature for neuralgic pain. Most of the patients fail to respond to medical treatments or succumb to complications of total anesthesia owing to surgical procedures. Herein, we tried a new treatment modality in patients suffering from postherpetic neuralgia with appreciable success in all the three cases that are presented in this paper. Streptomycin sulfate dissolved in 2% lidocaine solution was deposited at the peripheral branches on the involved nerves targeting the trigger zones, given weekly once for a maximum of 6 week period and continued once in 2 weeks if symptoms persisted. All patients were followed-up for 1 year and there was a marked improvement on follow-up.

Vaccination against and treatment of acute herpes zoster for prevention of post-herpetic neuralgia

Zostavax (zoster vaccine) is a 1-dose, high-potency, live, attenuated varicella zoster virus (VZV) vaccine that boosts VZV-specific cell-mediated immunity (CMI), and this is its presumed mechanism of action. Other strategies focus on preventing the major complication of HZ, post-herpetic neuralgia (PHN). Evidence that the vaccine is effective in older patients comes from the pivotal Shingles Prevention Study. That study demonstrated that HZ vaccine significantly reduced morbidity due to HZ and PHN in older patients. However, the duration of efficacy beyond 5 years after vaccination remains unclear. The Long-Term Persistence Substudy, currently under analysis, may provide additional data on the duration of efficacy for zoster vaccine. This review discusses vaccination against HZ, and further reviews recent pharmacotherapy for prevention of PHN.

Prevention of infection caused by immunosuppressive drugs in gastroenterology

Immunosuppressive therapy is frequently used to treat gastrointestinal diseases such as inflammatory bowel disease, autoimmune hepatitis, IgG4-related disease (autoimmune pancreatitis and sclerosing cholangitis) and in the post-transplantation setting. These drugs interfere with the immune system. The main safety concern with their use is the risk of infections. Certain infections can be prevented or their impact minimized. Physicians must adopt preventative strategies and should have a high degree of suspicion to recognize infections early and treat appropriately. This article reviews the risk factors for infections, the mechanism of action of immunosuppressive therapy and proposes preventive strategies.

Safety and immunogenicity of an AS01-adjuvanted varicella zoster virus subunit candidate vaccine (HZ/su): a phase-I, open-label study in Japanese adults

An adjuvanted recombinant subunit candidate vaccine (HZ/su) containing varicella zoster virus envelope glycoprotein E was developed for the prevention of herpes zoster and its complications. This study evaluated safety and reactogenicity of HZ/su in an ethnic Japanese population. This was a phase I, open-label and single-center study conducted between March and November of 2010 in Australia. Twenty healthy ethnic Japanese subjects, aged 18–30 y and 50–69 y (1:1) were enrolled. Subjects were administered two doses of HZ/su vaccine according to a 0, 2-mo schedule. Local and general solicited symptoms were recorded for 7 d post-vaccination. Unsolicited symptoms were recorded for 30 d post-vaccination. Serious adverse events (SAEs), new onset of autoimmune disease (NOAD), other potential immune mediated disorders and HZ cases were recorded throughout the study period. All 20 subjects were included in the according-to-protocol cohort for safety. A total of 18 subjects were included in the according-to-protocol cohort for immunogenicity: 10 in the 18–30 y age group and 8 in the 50–69 y age group. The most commonly reported local and general solicited symptoms were pain and fatigue in both groups. Back pain (in the 18–30 y age group) and chills (in the 50–69 y age group) were the most frequently reported unsolicited symptoms. There were no reports of death, SAEs, NOADs, other autoimmune mediated inflammatory disorder or suspected HZ cases. This study indicated that the two-dose regimen of HZ/su exhibited a clinically acceptable safety profile in healthy young and older ethnic Japanese adults.

Pregabalin treatment for peripheral neuropathic pain: a review of safety data from randomized controlled trials conducted in Japan and in the west

Two well-studied conditions of peripheral neuropathic pain are postherpetic neuralgia (PHN) and painful diabetic peripheral neuropathy (DPN). Several pregabalin trials for peripheral neuropathic pain have been conducted in the West, but limited data are available for Japan. As ethnicity may influence health risks, differences may be evident in safety data from pregabalin trials in Japan and in the West. The objectives of this review were to compare large pooled safety data from randomized controlled trials evaluating pregabalin for the treatment of PHN or DPN in the West with data from two (one PHN, N = 371; one DPN, N = 314) similar trials in Japan. Longer-term safety data from Japanese open-label extension studies were also reviewed in these neuropathic pain populations. Published and unpublished Pfizer-supported pregabalin trials were identified and sourced from internal Pfizer records. A PubMed search to check for inclusiveness was conducted on 2 November 2011 using the following criteria: 'diabetic peripheral neuropathy' OR 'postherpetic neuralgia' OR 'neuropathic pain' AND 'pregabalin', with limits set for clinical and randomized controlled trials published in English. Five PHN trials (N = 1250) and nine DPN trials (N = 2554) were identified as suitable for inclusion based on methodological comparability. Descriptive safety data from the original trials were reviewed and the most commonly reported adverse events (AEs; dizziness, somnolence, peripheral oedema and weight gain) were identified to be of primary interest. The majority of AEs were of mild to moderate severity in Japanese and Western populations. The most commonly reported AE data (all-causality) with pregabalin (regardless of dose) in Japan (dizziness: PHN = 31.1%; DPN = 24.6%, and somnolence: PHN = 28.6%; DPN = 25.7%) were compared with pooled data from the Western trials (dizziness: PHN = 24.9%; DPN = 23.0%, and somnolence: PHN = 15.1%; DPN = 13.4%). Further assessment of these pooled AE (all-causality) data showed that dizziness and somnolence appeared early in the course of pregabalin treatment, but resolved before the end of the treatment in the majority of PHN and DPN patients (maximum duration of trials was 13 weeks). The slightly higher incidence of dizziness and somnolence in the two Japanese trials than that seen in the Western trials may reflect an increased exposure to pregabalin per fixed dose due to the lower mean bodyweight of the Japanese versus Western populations (on a mg/kg basis). However, of the participants who experienced these AEs (all-causality), the proportion who withdrew from the trials in Japan (dizziness: PHN = 23.5%; DPN = 18.2%, and somnolence: PHN = 10.3%; DPN = 10.9%) were comparable with the proportion who withdrew from trials in the West (dizziness: PHN = 16.0%; DPN = 29.3%, and somnolence: PHN = 19.4%; DPN = 34.2%). In Japan, 12.5% (PHN) and 15.1% (DPN) of patients experienced peripheral oedema as an AE (all-causality) compared with 8.8% (PHN) and 10.3% (DPN) in the West. Weight gain as an AE (all-causality) was experienced in 11.7% (PHN) and 13.4% (DPN) of patients in Japan compared with 3.8% (PHN) and 7.0% (DPN) in the West, but stabilized with continued treatment. Despite the lower mean bodyweight in Japanese versus Western patients, the PHN and DPN patients in Japan had stable blood glucose and HbA(1c) levels throughout the trials. The results of this review indicate safety outcomes in pregabalin trials are comparable between patients in Japan and those in the West. While managing peripheral neuropathic pain with pregabalin treatment, all patients should be observed closely for the incidence of dizziness and somnolence, especially at the beginning of treatment. These patients should also be monitored for evidence of peripheral oedema and weight gain during stable treatment, regardless of the source of neuropathic pain.

Diagnosing and managing postherpetic neuralgia

Postherpetic neuralgia (PHN) represents a potentially debilitating and often undertreated form of neuropathic pain that disproportionately affects vulnerable populations, including the elderly and the immunocompromised. Varicella zoster infection is almost universally prevalent, making prevention of acute herpes zoster (AHZ) infection and prompt diagnosis and aggressive management of PHN of critical importance. Despite the recent development of a herpes zoster vaccine, prevention of AHZ is not yet widespread or discussed in PHN treatment guidelines. Diagnosis of PHN requires consideration of recognized PHN signs and known risk factors, including advanced age, severe prodromal pain, severe rash, and AHZ location on the trigeminal dermatomes or brachial plexus. PHN pain is typically localized, unilateral and chronic, but may be constant, intermittent, spontaneous and/or evoked. PHN is likely to interfere with sleep and daily activities. First-line therapies for PHN include tricyclic antidepressants, gabapentin and pregabalin, and the lidocaine 5 % patch. Second-line therapies include strong and weak opioids and topical capsaicin cream or 8 % patch. Tricyclic antidepressants, gabapentinoids and strong opioids are effective but are also associated with systemic adverse events that may limit their use in many patients, most notably those with significant medical comorbidities or advanced age. Of the topical therapies, the topical lidocaine 5 % patch has proven more effective than capsaicin cream or 8 % patch and has a more rapid onset of action than the other first-line therapies or capsaicin. Given the low systemic drug exposure, adverse events with topical therapies are generally limited to application-site reactions, which are typically mild and transient with lidocaine 5 % patch, but may involve treatment-limiting discomfort with capsaicin cream or 8 % patch. Based on available clinical data, clinicians should consider administering the herpes zoster vaccine to all patients aged 60 years and older. Clinicians treating patients with PHN may consider a trial of lidocaine 5 % patch monotherapy before resorting to a systemic therapy, or alternatively, may consider administering the lidocaine 5 % patch in combination with a tricyclic antidepressant or a gabapentinoid to provide more rapid analgesic response and lower the dose requirement of systemic therapies.

Validation of the Self-Assessment of Treatment Questionnaire among Patients with Postherpetic Neuralgia

Introduction. A five-item Self-Assessment of Treatment (SAT) was developed to assess improvement and satisfaction with treatment associated with the application of a novel high concentration 8% capsaicin topical patch in clinical trials in patients with postherpetic neuralgia (PHN). This study evaluated the item performance and psychometric properties of the SAT. Methods. The SAT, Brief Pain Inventory, SF-36v2, Short-Form McGill Pain Questionnaire, and Patient and Clinician Global Impression of Change (PGIC; CGIC) scores were measured in two 12-week Phase 3 clinical trials. Factor analysis assessed the underlying factor structure, followed by examination of the reliability and validity of the multi-item domain. Results. Pooled data from 698 patients completing SAT after 12 weeks of treatment were analyzed. A one-factor model combining three of the five items emerged as the optimal solution. Internal consistency reliability of this treatment efficacy factor was high (Cronbach's alpha = 0.89). Construct validity was demonstrated by moderate to high correlations with change in other study endpoints. SAT mean scores consistently discriminated between patient change groups defined by PGIC and CGIC. Conclusions. The measurement properties of the three-item version of SAT are valid and reliable for assessment of treatment with a high concentration capsaicin patch among patients with PHN.

NCI, NHLBI/PBMTC first international conference on late effects after pediatric hematopoietic cell transplantation: persistent immune deficiency in pediatric transplant survivors

Defective immune reconstitution is a major barrier to successful hematopoietic cell transplantation (HCT), and has important implications in the pediatric population. There are many factors that affect immune recovery, including stem cell source and graft-versus-host disease (GVHD). Complete assessment of immune recovery, including T and B lymphocyte evaluation, innate immunity, and response to neoantigens, may provide insight as to infection risk and optimal time for immunizations. The increasing use of cord blood grafts requires additional study regarding early reconstitution and impact upon survival. Immunization schedules may require modification based upon stem cell source and immune reconstitution, and this is of particular importance as many children have been incompletely immunized, or not at all, before school entry. Additional studies are needed in children post-HCT to evaluate the impact of differing stem cell sources upon immune reconstitution, infectious risks, and immunization responses.

Tolerability of NGX-4010, a capsaicin 8% dermal patch, following pretreatment with lidocaine 2.5%/prilocaine 2.5% cream in patients with post-herpetic neuralgia

Background

Post-herpetic neuralgia (PHN) is a common type of neuropathic pain that can severely affect quality of life. NGX-4010, a capsaicin 8% dermal patch, is a localized treatment that can provide patients with significant pain relief for up to 3 months following a single 60-minute application. The NGX-4010 application can be associated with application-site pain and in previous clinical trials pretreatment with a topical 4% lidocaine anesthetic was used to enhance tolerability. The aim of the current investigation was to evaluate tolerability of NGX-4010 after pretreatment with lidocaine 2.5%/prilocaine 2.5% anesthetic cream.

Methods

Twenty-four patients with PHN were pretreated with lidocaine 2.5%/prilocaine 2.5% cream for 60 minutes before receiving a single 60-minute application of NGX-4010. Tolerability was assessed by measuring patch application duration, the proportion of patients completing over 90% of the intended treatment duration, application site-related pain using the Numeric Pain Rating Scale (NPRS), and analgesic medication use to relieve such pain. Safety was assessed by monitoring adverse events (AEs) and dermal irritation using dermal assessment scores.

Results

The mean treatment duration of NGX-4010 was 60.2 minutes and all patients completed over 90% of the intended patch application duration. Pain during application was transient. A maximum mean change in NPRS score of +3.0 was observed at 55 minutes post-patch application; pain scores gradually declined to near pre-anesthetic levels (+0.71) within 85 minutes of patch removal. Half of the patients received analgesic medication on the day of treatment; by Day 7, no patients required medication. The most common AEs were application site-related pain, erythema, edema, and pruritus. All patients experienced mild dermal irritation 5 minutes after patch removal, which subsequently decreased; at Day 7, no irritation was evident. The maximum recorded dermal assessment score was 2.

Conclusion

NGX-4010 was well tolerated following pretreatment with lidocaine 2.5%/prilocaine 2.5% cream in patients with PHN. The tolerability of the patch application appeared comparable with that seen in other studies that used 4% lidocaine cream as the pretreatment anesthetic. This study is registered at http://www.clinicaltrials.gov as number NCT00916942.

Spinal cord stimulation in the treatment of postherpetic neuralgia in patients with chronic kidney disease: a case series and review of the literature

BACKGROUND

Postherpetic neuralgia (PHN) is usually managed pharmacologically. It is not uncommon for patients with chronic kidney disease (CKD) to suffer from PHN. It is difficult to prescribe a sufficient dose of anticonvulsants for intractable pain because of the decreased glomerular filtration rate. If the neural blockade and pulsed radiofrequency ablation provide only short-term amelioration of pain, spinal cord stimulation (SCS) with a low level of evidence may be used only as a last resort. This study was done to evaluate the efficacy of spinal cord stimulation in the treatment of PHN in patients with CKD.

METHODS

PHN patients with CKD who needed hemo-dialysis who received insufficient relief of pain over a VAS of 8 regardless of the neuropathic medications were eligible for SCS trial. The follow-up period was at least 2 years after permanent implantation.

RESULTS

Eleven patients received percutaneous SCS test trial from Jan 2003 to Dec 2007. Four patients had successfully received a permanent SCS implant with their pain being tolerable at a VAS score of less than 3 along with small doses of neuropathic medications.

CONCLUSIONS

SCS was helpful in managing tolerable pain levels in some PHN patients with CKD along with tolerable neuropathic medications for over 2 years.

Familial occipital and nervus intermedius neuralgia in a Swiss family

Familial trigeminal neuralgia has been reported in 1–2% of cases consistent with an autosomal dominant inheritance. We present a Swiss family with several members suffering from occipital and nervus intermedius neuralgia alone or in combination. We suggest that peripheral sensory anastomoses or central convergence of afferent pathways could explain neuralgia affecting two cranial nerves. The pedigree has two main characteristics: (1) affected individuals in two generations and (2) in the first generation the father is affected, in the second generation all women are affected, and none of the men. This is suggestive of an X-linked dominant or an autosomal dominant mode of inheritance.

Compounds that target host cell proteins prevent varicella-zoster virus replication in culture, ex vivo, and in SCID-Hu mice

Varicella-zoster virus (VZV) replicates in quiescent T cells, neurons, and skin cells. In cultured fibroblasts (HFFs), VZV induces host cyclin expression and cyclin-dependent kinase (CDK) activity without causing cell cycle progression. CDK1/cyclin B1 phosphorylates the major viral transactivator, and the CDK inhibitor roscovitine prevents VZV mRNA transcription. We investigated the antiviral effects of additional compounds that target CDKs or other cell cycle enzymes in culture, ex vivo, and in vivo. Cytotoxicity and cell growth arrest doses were determined by Neutral Red assay. Antiviral effects were evaluated in HFFs by plaque assay, genome copy number, and bioluminescence. Positive controls were acyclovir (400 microM) and phosphonoacetic acid (PAA, 1 mM). Test compounds were roscovitine, aloisine A, and purvalanol A (CDK inhibitors), aphidicolin (inhibits human and herpesvirus DNA polymerase), l-mimosine (indirectly inhibits human DNA polymerase), and DRB (inhibits casein kinase 2). All had antiviral effects below the concentrations required for cell growth arrest. Compounds were tested in skin organ culture at EC(99) doses; all prevented VZV replication in skin, except for aloisine A and purvalanol A. In SCID mice with skin xenografts, roscovitine (0.7 mg/kg/day) was as effective as PAA (36 mg/kg/day). The screening systems described here are useful models for evaluating novel antiviral drugs for VZV.

Tumor necrosis factor blockade and the risk of viral infection

Tumor necrosis factor (TNF) blockers are widely used to treat rheumatoid arthritis and other chronic inflammatory diseases. Many studies have demonstrated an increased risk of opportunistic infections such as tuberculosis and fungal infection in patients treated with TNF blockers, which is thought to be related to the primary role of TNF both in host defense and in the immune response. Little is known, however, about the association between TNF blockade and the development of viral infection. Owing to the critical role of TNF in the control of viral infection, depletion of this cytokine with TNF blockers could facilitate the development or reactivation of viral infection. A number of large observational studies have found an increased risk of herpes zoster in patients receiving TNF blockers for the treatment of rheumatoid arthritis. This Review draws attention to the risk of several viral infections, including HIV, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, and human papillomavirus, in patients receiving TNF-blocking therapy for chronic inflammatory conditions. In addition, implications for clinical practice and possible preventative approaches are discussed.

Targeting neuroprotection as an alternative approach to preventing and treating neuropathic pain

Neuropathic pain syndromes arise from dysfunction of the nerve itself, through traumatic or nontraumatic injury. Unlike acute pain syndromes, the pain is long-lasting and does not respond to common analgesic therapies. Drugs that disrupt nerve conduction and transmission or central sensitization, currently the only effective treatments, are only modestly effective for a portion of the patients suffering from neuropathic pain and come with the cost of serious adverse effects. Neurodegeneration, as a reaction to nerve trauma or chronic metabolic or chemical intoxication, appears to be an underlying cause of neuropathic pain. Identifying mechanisms of neurodegeneration and designing neuroprotective therapies is an ambitious goal toward treating or even preventing the development of these disabling disorders.

Postherpetic neuralgia: from preclinical models to the clinic

Postherpetic neuralgia (PHN), a common complication of herpes zoster, which results from reactivation of varicella zoster virus, is a challenging neuropathic pain syndrome. The incidence and severity of herpes zoster and PHN increases with immune impairment or age and may become a greater burden both in terms of health economics and individual suffering. A clearer understanding of the underlying mechanisms of this disease and translation of preclinical outcomes to the clinic may lead to more efficacious treatment options. Here we give an overview of recent findings from preclinical models and clinical research on PHN.

Acupuncture in acute herpes zoster pain therapy (ACUZoster) - design and protocol of a randomised controlled trial

Background

Acute herpes zoster is a prevalent condition. One of its major symptoms is pain, which can highly influence patient's quality of life. Pain therapy is limited. Acupuncture is supposed to soften neuropathic pain conditions and might therefore act as a therapeutic alternative. Objective of the present study is to investigate whether a 4 week semi-standardised acupuncture is non-inferior to sham laser acupuncture and the anticonvulsive drug gabapentine in the treatment of pain associated with herpes zoster.

Methods/Design

Three-armed, randomised, placebo-controlled trial with a total follow-up time of 6 months. Up to estimated 336 patients (interim analyses) with acute herpes zoster pain (VAS > 30 mm) will be randomised to one of three groups (a) semi-standardised acupuncture (168 patients); (b) gabapentine with individualised dosage between 900–3600 mg/d (84 patients); (c) sham laser acupuncture. Intervention takes place over 4 weeks, all patients will receive analgesic therapy (non-opioid analgesics: metamizol or paracetamol and opioids: tramadol or morphine). Therapy phase includes 4 weeks in which group (a) and (c) consist of 12 sessions per patient, (b) visits depend on patients needs. Main outcome measure is to assess the alteration of pain intensity before and 1 week after treatment sessions (visual analogue scale VAS 0–100 mm). Secondary outcome measure are: alteration of pain intensity and frequency of pain attacks; alteration of different aspects of pain evaluated by standardised pain questionnaires (NPI, PDI, SES); effects on quality of life (SF 36); analgesic demand; alteration of sensoric perception by systematic quantitative sensory testing (QST); incidence of postherpetic neuralgia; side effects and cost effectiveness. Credibility of treatments will be assessed.

Discussion

This study is the first large-scale randomised placebo controlled trial to evaluate the efficacy of acupuncture compared to gabapentine and sham treatment and will provide valuable new information about the clinical and physiological effects of acupuncture and gabapentine in the treatment of acute herpes zoster pain. The study has been pragmatically designed to ensure that the study findings can be implemented into clinical practice if acupuncture can be shown to be an effective treatment strategy in acute herpes zoster pain.

Trial registration

NCT00885586