Treatment patterns of postherpetic neuralgia patients before and after the launch of pregabalin and its effect on medical costs: Analysis of Japanese claims data provided by Japan Medical Data Center

A systematic literature review of the epidemiology and burden of herpes zoster in selected locales in Asia Pacific

Herpes zoster (HZ) is a painful rash which typically affects older adults. This is of concern in Asia-Pacific given its aging population. As HZ epidemiology and burden are evolving, this systematic literature review aimed to update the current understanding of HZ burden and associated costs for selected Asia-Pacific locales. MEDLINE and Embase were searched for English articles of HZ studies conducted in Australia, China, Hong Kong, Japan, Korea, New Zealand, Singapore, and Taiwan. Eligible outcomes included HZ incidence and prevalence, occurrence of HZ-related complications, healthcare resource utilization, costs, and HZ-associated quality of life outcomes. This paper focused on HZ data in the general adult population (N = 90 articles). Substantial HZ-related disease and economic burden were observed in these locales, consistent with global trends. These findings reinforce the increasing burden of HZ and need for preventive strategies, which may include raising awareness and encouraging timely vaccination.

Combined effect of Neurotropin® and methylcobalamin on postherpetic neuralgia in mice infected with herpes simplex virus type-1

BACKGROUND

Postherpetic pain (PHP) is difficult to control. Although Neurotropin® (NTP) and methylcobalamin (MCB) are often prescribed to treat the pain, the efficacy of combined treatment for PHP remains imcompletely understood.

OBJECTIVE

In this study, we investigate the combined effects of NTP and MCB on PHP in mice.

METHODS

NTP and MCB were administered from day 10-29 after herpes simplex virus type-1 (HSV-1) infection. The pain-related responses were evaluated using a paint brush. The expression of neuropathy-related factor (ATF3) and nerve repair factors (GAP-43 and SPRR1A) in the dorsal root ganglion (DRG) and neurons in the skin were evaluated by immunohistochemical staining. Nerve growth factor (NGF) and neurotrophin-3 (NT3) mRNA expression levels were evaluated using real-time PCR.

RESULTS

Repeated treatment with NTP and MCB after the acute phase inhibited PHP. Combined treatment with these drugs inhibited PHP at an earlier stage than either treatment alone. In the DRG of HSV-1-infected mice, MCB, but not NTP, decreased the number of cells expressing ATF3 and increased the number of cells expressing GAP-43- and SPRR1A. In addition, MCB, but not NTP, also increased and recovered non-myelinated neurons decreased in the lesional skin. NTP increased the mRNA levels of NTF3 in keratinocytes, while MCB increased that of NGF in Schwann cells.

CONCLUSION

These results suggest that combined treatment with NTP and MCB is useful for the treatment of PHP. The combined effect may be attributed to the different analgesic mechanisms of these drugs.

Cost-Effectiveness Analysis Update of the Adjuvanted Recombinant Zoster Vaccine in Japanese Older Adults

Introduction

This study aimed to update cost-effectiveness and public health impact estimates of the two-dose recombinant zoster vaccine (RZV) compared with no vaccination against herpes zoster (HZ) in the Japanese population aged 65 years. List price of the vaccine and latest RZV efficacy and waning estimates were incorporated.

Methods

A multicohort static Markov model with a cycle length of 1 year was used to follow a hypothetical cohort of one million people aged 65 years over their remaining lifetime (base case). Age-stratified vaccine efficacy and waning rates were updated on the basis of the latest clinical trial data (interim ZOE-LTFU; NCT02723773). First-dose coverage was assumed at 40%, and second-dose compliance was assumed at 95%. Costs and outcomes were discounted at 2% annually, and the incremental cost-effectiveness ratio (ICER) was calculated from payer and societal perspectives. The societal perspective considered productivity loss due to suffering HZ, or due to suffering HZ and time required for vaccination. Sensitivity analyses explored the overall uncertainties in the model. Scenario analyses for Japanese adults aged 50, 60, 70, 80, ≥ 50, and ≥ 65 years (main scenario) were conducted. An ICER below ¥5–6 million/quality-adjusted life-year (QALY) was considered cost-effective.

Results

RZV was estimated to prevent 71,423 HZ cases and 15,858 post-herpetic neuralgia (PHN) cases per million people aged 65 years compared with no vaccine in Japan. The ICER was ¥4,205,515 from a payer perspective and was most sensitive to assumptions regarding vaccine efficacy waning, proportion of patients with HZ developing PHN, and HZ incidence. From societal perspectives, ICERs were ¥3,854,192 (productivity loss from suffering HZ only) and ¥4,622,212 (productivity loss from suffering HZ and time required for vaccination). Overall, the results were considered robust under extensive sensitivity and scenario analyses.

Conclusion

Vaccination against HZ with RZV is cost-effective compared with no vaccination in Japanese adults aged 65 years.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-022-00744-8.

Research Trends and Hotspots on Herpes Zoster: A 10-Year Bibliometric Analysis (2012-2021)

Purpose

Herpes zoster infection, with its considerable burden to individuals and society, remains a challenge around the world. However, to the knowledge of the authors, little bibliometric quantitative or qualitative analysis has been carried out to evaluate herpes zoster research. This study aimed to use a bibliometric analysis to evaluate current publication trends and hotspots on herpes zoster research worldwide, in order to advance research in this field.

Methods

Relevant publications from January 2012 to December 2021 were collected from the Web of Science Core Collection database. Citespace (V5.8.R3) was used to analyze the research points, including publication countries, institutions and authors, cited author, cited reference and their clustering, and keyword co-occurrence, and burst keyword to acquire research trends and hotspots.

Results

A total of 9,259 publications were obtained, with a steady increase in the number of annual publications during the decade. Articles were the main type of publication. The United States is the leading country in this research, and the University of Colorado has the highest influence in this field. Oxman is the most representative author, with a main research interest in herpes zoster vaccines. The top five cited authors' publications focused on herpes zoster vaccines, molecular mechanisms, and postherpetic neuralgia. A co-citation map resulted 19 main clusters, and revealed that vaccines, postherpetic neuralgia, treatments, varicella zoster virus and its mechanisms, and epidemiology of herpes zoster were the current research focus after clustering co-cited publications. Human herpesviruses, antiviral prophylaxis, rheumatoid arthritis, recombinant zoster vaccine, varicella vaccination and postherpetic neuralgia were the top clusters after co-occurrence keywords analysis. Moreover, burst keywords detection showed that the subunit vaccine was the new hotspot in the field of herpes zoster.

Conclusion

This bibliometric study defined the overall prospects in the field of herpes zoster and provided valuable instruction for the ongoing research. The keyword "subunit vaccine" indicated that a vaccine for herpes zoster prevention was the hotspot. Efforts to prevent varicella zoster virus infection will be essential to improve herpes zoster outcomes.

Mirogabalin in Japanese Patients with Renal Impairment and Pain Associated with Diabetic Peripheral Neuropathy or Post-Herpetic Neuralgia: A Phase III, Open-Label, 14-Week Study

Purpose

Mirogabalin was recently approved in Japan for the treatment of peripheral neuropathic pain, based on data from clinical trials in diabetic peripheral neuropathic pain (DPNP) and post-herpetic neuralgia (PHN), common clinical conditions which cause intense distress for patients. We characterized the safety and tolerability of mirogabalin in Japanese patients with renal impairment.

Patients and Methods

This multicenter, open-label study (ClinicalTrials.gov identifier NCT02607280) enrolled renally impaired individuals aged ≥20 years diagnosed with DPNP or PHN, and with an average daily pain score (ADPS) of ≥4 over the 7 days prior to treatment initiation. Mirogabalin dosage was titrated for 2 weeks, followed by a fixed dose for 12 weeks according to degree of renal impairment: 7.5 mg twice daily for moderate impairment and 7.5 mg once daily for severe impairment. The primary endpoint was safety and tolerability of mirogabalin, evaluated via treatment-emergent adverse events (TEAEs). Secondary efficacy endpoints included change in ADPS from baseline to Week 14.

Results

Overall, 35 patients were enrolled (30 with moderate and 5 with severe renal impairment). Most TEAEs were mild or moderate in severity; the most commonly reported were nasopharyngitis (22.9%) and somnolence (11.4%). Only 4 patients (11.4%) discontinued treatment due to TEAEs. Mirogabalin significantly decreased ADPS from baseline in patients with renal impairment; least squares mean change from baseline at Week 14 was −1.9 (95% confidence interval: −2.8, −1.0).

Conclusion

Mirogabalin was well tolerated and significantly reduced pain levels when used to treat DPNP/PHN at a fixed dose of 7.5 mg once or twice daily in patients with renal impairment.

Prevalence, disease burden, and treatment reality of patients with severe, uncontrolled asthma in Japan

BACKGROUND

The severe asthma and severe, uncontrolled asthma (SUA) populations in Japan are not well-studied. We investigated the prevalence of continuously treated severe asthma and SUA patients, their disease burden, and the treatment reality via a Japanese health insurance claims database.

METHODS

Continuously treated asthma patients (patients prescribed inhaled corticosteroids for asthma ≥4 times in the past year) aged ≥17 years at the index date (latest visit between April 2014 and March 2015 for asthma treatment) were included in this analysis (KEIFU study, UMIN000027695). Asthma severity and control status at the index date were defined using modified criteria of ERS/ATS guidelines. Asthma hospitalization, oral corticosteroid (OCS) use, and total medical expenses were calculated using data up to 12 months post-index date.

RESULTS

We identified 10,579 patients as continuously treated asthma patients. Of these, 823 (7.8%) had severe asthma; 267 (2.5%) and 556 (5.3%) patients had SUA and severe, controlled asthma (SCA), respectively. Compared with SCA and mild to moderate asthma patients, a greater percentage of SUA patients required hospitalization (13.7%, 6.2%, and 3.0%, respectively) and were prescribed OCSs (67.4%, 45.9%, and 16.2%, respectively). Yearly total medical expenses were also greater for SUA patients (mean [standard deviation]: 8346 [12,280], vs 5989 [10,483] and 3422 [8800] USD, respectively).

CONCLUSIONS

The percentages of severe asthma and SUA patients continuously treated in Japan were obtained through this large-scale analysis using a health insurance claims database. SUA patients had greater medical and economic burdens, suggesting more appropriate treatment is required according to the treatment guidelines.

Cost-Effectiveness of the Adjuvant Recombinant Zoster Vaccine in Japanese Adults Aged 65 Years and Older

INTRODUCTION

The incidence of herpes zoster (HZ) rises steeply after the age of 50 years and the number of HZ cases and complications such as postherpetic neuralgia (PHN) is predicted to increase because of the ageing population. The objective of this study was to estimate the cost-effectiveness of recombinant zoster vaccine (RZV) compared with no vaccine for the Japanese population aged ≥ 65 years.

METHODS

A multi-cohort static Markov model with a cycle length of 1 year was used to follow a hypothetical cohort of 1 million people aged ≥ 65 years over their remaining lifetime. Vaccination at ≥ 65 years was used in alignment with the influenza and pneumococcal vaccines recommended from 65 years. Japan-specific data inputs for the model were obtained from local data sources. Age-stratified vaccine efficacy and waning rates were based on published clinical trial data. In the base-case analysis, vaccine coverage was assumed to be 40% with a second dose compliance of 95%. Costs and outcomes were discounted at 2% annually and the incremental cost-effectiveness ratio (ICER) was calculated from both a payer's and the societal perspective. Sensitivity analyses were carried out to explore the overall uncertainty in the model.

RESULTS

Vaccination with RZV was projected to prevent 48,943 HZ cases and 12,136 PHN cases per million people aged ≥ 65 years compared with no vaccination. The incremental costs and quality-adjusted life years (QALYs) gained were ¥9.99 billion and 2314 QALYs from a payer's perspective and ¥9.34 billion and 2314 QALYs from a societal perspective. The resulting ICERs were approximately ¥4,320,000 and ¥4,040,000 per QALY gained from a payer's and the societal perspective, respectively. The ICER remained below a willingness-to-pay threshold of ¥5,000,000 for most sensitivity analyses carried out.

CONCLUSION

Vaccination against HZ with RZV would be cost-effective compared with no vaccination for the Japanese population aged ≥ 65 years.

TRIAL REGISTRATION

GSK study identifier: HO-16-17837.

FUNDING

GlaxoSmithKline Biologicals SA.

The efficacy of pregabalin for the treatment of neuropathic pain in Japanese subjects with moderate or severe baseline pain

Purpose

Although analyses of pooled clinical trial data have reported how international populations respond to pregabalin by baseline neuropathic pain (NeP) severity, no studies have evaluated this specifically in patients from Japan. Thus, this post hoc pooled analysis evaluated the efficacy of pregabalin in Japanese subjects for treating moderate or severe baseline NeP.

Patients and methods

Data were pooled from three placebo-controlled trials enrolling Japanese subjects with postherpetic neuralgia (PHN), diabetic peripheral neuropathy (DPN), and spinal cord injury (SCI). The efficacy of pregabalin was evaluated by baseline pain severity (moderate or severe NeP). The trials on PHN and DPN included a 1-week titration of pregabalin from 150 mg/day to 300 or 600 mg/day; the SCI trial included a 4-week dose optimization phase (150 mg/day, titrated up to 600 mg/day). Treatment durations were 13–16 weeks (excluding 1-week taper periods), and pregabalin was administered in two divided doses per day.

Results

Mean baseline pain scores and demographic characteristics were comparable between treatment cohorts. Pregabalin treatment significantly reduced pain scores from baseline to endpoint compared with placebo in subjects with both moderate (P<0.001) and severe (P<0.05) baseline pain. Significant improvements in mean sleep scores from baseline to endpoint were associated with pregabalin compared with placebo in subjects with both moderate and severe baseline pain (both P<0.0001). A greater proportion of subjects in both pain cohorts achieved a ≥30% reduction in pain from baseline with pregabalin vs placebo (P<0.05). Higher proportions of pregabalin-treated vs placebo-treated subjects shifted to a less severe pain category at endpoint. Consistent with the known safety profile of pregabalin, common adverse events included dizziness, somnolence, weight gain, and peripheral edema.

Conclusion

Pregabalin demonstrated efficacy for pain relief and sleep improvement with a consistent safety profile in Japanese subjects with either moderate or severe baseline pain severity.

ClinicalTrials.gov identifiers

NCT0039490130, NCT0055347522, NCT0040774524

The efficacy of pregabalin for acute pain control in herpetic neuralgia patients: A meta-analysis

OBJECTIVE

This meta-analysis aimed to illustrate the efficacy and safety of preganalin for pain management in patients with postherpetic neuralgia (PHN).

METHODS

In July 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and Google database. Data on patients with PHN that compared pregabalin versus placebo were retrieved. The endpoints were the visual analog scale (VAS) at 8 weeks, the percentage of 30% and 50% pain responders; sleep interference score and improvement in patient global impression of change (PGIC). After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary.

RESULTS

Seven clinical studies with 2192 patients (pregabalin group = 1381, control group = 811) were finally included in the meta-analysis. Pregabalin was associated with reduced pain scores at 8 weeks, corresponding to a reduction of 11.23 points (95% CI, -14.33, -8.13, P = .000) on a 100-point VAS. Pregabalin was also associated with a more percentage of 30% and 50% pain responders than controls (P < .05). Meanwhile, pregabalin can decrease sleep interference score and improvement in PGIC than control groups (P < .05).

CONCLUSIONS

Pregabalin was efficacious in the reduction of postoperative pain and improvement the sleep quality in patients with PHN.

Economic Burden of Herpes Zoster and Post-Herpetic Neuralgia in Adults 60 Years of Age or Older: Results from a Prospective, Physician Practice-Based Cohort Study in Kushiro, Japan

BACKGROUND AND OBJECTIVE

Herpes zoster has a high incidence rate among people aged ≥ 60 years and can lead to serious complications such as post-herpetic neuralgia. There are currently no data on the economic burden of herpes zoster and post-herpetic neuralgia in Japan, and the objective of this study was to address this gap.

METHODS

A total of 412 patients aged ≥ 60 years diagnosed with herpes zoster were recruited. Demographic, clinical, and healthcare resource utilization data on patients with herpes zoster or post-herpetic neuralgia collected via case report forms were used to estimate direct medical cost. Data obtained from a questionnaire survey among patients with herpes zoster/post-herpetic neuralgia were used to estimate transportation cost and productivity loss.

RESULTS

The mean number of outpatient visits was 5.7. Prescription medications were the main cost driver accounting for 60% of the direct medical cost. The mean direct medical and total herpes zoster-related costs per patient were ¥43,925 and ¥57,112, respectively, and were higher in patients with post-herpetic neuralgia than in those with herpes zoster without complications. Direct medical cost represented 77%, productivity loss 19%, and transportation cost 4% of the total.

CONCLUSIONS

This is the first study of the economic burden of herpes zoster and post-herpetic neuralgia in Japan and it demonstrated substantial direct medical cost as a result of the multiple outpatient visits and prescription medications required. These findings provide baseline data for possible future economic evaluations of new herpes zoster/post-herpetic neuralgia interventions.

TRIAL REGISTRATION

This cost analysis is part of a prospective, physician practice-based cohort study conducted between June 2013 and February 2015 in Kushiro, Japan (Clinicaltrials.gov identifier NCT01873365, registered on 6 June, 2013).