Pharmaceutical Industry at a Glance Trends in Pediatric Atopic Dermatitis Testing and Prescription Drugs Based on NDB Open Data

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The Office of Pharmaceutical Industry Research Shinji Tsubakihara, Senior Researcher

Summary

1. Introduction

The "School Health Statistics Survey " ¹⁾ is a sample survey that aims to clarify the state of development and health of infants, children, and students in schools as a core statistical survey based on the Statistics Law (survey for compiling school health statistics, which are core statistics). According to the website of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the survey started in 1900 under the name of "Physical Examination Statistics for Students and Children," was renamed "School Health Statistics" in 1948, and was revised to the current name in 1960, and as of December 2025, the survey results for the 2024 school year have been published. As of December 2025, the survey results for the 2024 fiscal year have been published. The survey covers infants, children, and students between the ages of 5 and 17 (as of April 1) enrolled in kindergartens, elementary schools, junior high schools, compulsory education schools, high schools, secondary education schools, and certified kindergarten for children with special needs, all of which are designated in advance by the Minister of Education, Culture, Sports, Science and Technology.

The sampling method used is a stratified two-stage random sampling method for the growth condition survey of children, etc. and a stratified village sampling method for the health condition survey of children, etc. The survey items are: (1) growth condition survey: (1) height (2) weight, (2) health condition survey: （Health status survey: (1) Nutritional status; (2) Spine, thorax, and limbs; (3) Naked eye vision; (4) Eye diseases and abnormalities; (5) Hearing loss; (6) Ear, nose, and throat diseases; (7) Skin diseases; (8) Examination for tuberculosis; (9) Tuberculosis; (10) Electrocardiogram abnormalities; (11) Heart; (12) Protein detection; (13) Urine sugar detection; (14) Other diseases and abnormalities; (15) Dental and oral diseases The survey was designed to maintain a target accuracy of less than 5% for each survey item. (7) The estimated incidence of "atopic dermatitis" in the skin diseases section, and "asthma," "kidney disease," "speech disorder," "asthma" in the other diseases/abnormalities section, and "atopic dermatitis" in the other diseases/abnormalities section. The estimated incidence of "asthma," "kidney disease," "speech disorders," and "other diseases/abnormalities" are shown in the ⒁Other diseases/abnormalities section. Only atopic dermatitis, tuberculosis, dental caries, and asthma are specifically listed. Each prefectural government actively publishes information on the developmental status of infants, children, and students in its area, as well as the prevalence of diseases and laboratory abnormalities in comparison with the national average, in order to raise awareness of child health care in the local government. In this study, we focused on the prevalence of atopic dermatitis in children and its trends among diseases and laboratory abnormalities in the School Health Statistics Survey, and ^{used the} NDB Open Data (hereinafter referred to as NDBOD) ²⁾ to examine the number of calculations and yearly trends of specific tests for atopic dermatitis in pediatric patients, the number of calculations for the conventional treatment of atopic dermatitis, the number of calculations for topical steroids and the number of calculations for the recent treatment of atopic dermatitis. We will observe the relationship between the number of prescriptions of topical steroids and drugs with novel pharmacological actions, which have recently become a game changer in the treatment of atopic dermatitis, in pediatric patients and the yearly changes in the number of prescriptions of these drugs.

Survey Methodology

We collected atopic dermatitis incidence rates for infants, children, and students in kindergartens, elementary schools, junior high schools, and high schools from the 2015-2024 School Health Statistics Survey by school type, gender, and city size, and calculated the average annual percent change (APC) of the incidence rate. The definition of "affected" here is those who were determined by school physicians based on school physical examinations. In addition, a person is also considered a patient if he or she is not diagnosed with a disease or abnormality on physical examination but is diagnosed with a disease or abnormality by a physician at a medical institution, and the school is aware of this fact. However, if the patient is diagnosed as having no suspected illness or abnormality after treatment, and is judged to be under observation, he or she is not recorded as a "patient. The number of subjects in each year's health status survey is shown in Appendix 1 at the end of this report.

The number of calculated tests for atopic dermatitis and the quantity of prescribed drugs for treatment were taken from the NDBOD 2nd (FY 2015) to 10th (FY 2023) annual survey, and the quantity of prescribed drugs for males and females aged 0-19 years were tabulated by 5-year age group. For convenience, the 0-4 age group and the 5-9 age group are referred to as the lower age group, and the 10-14 age group and the 15-19 age group are referred to as the upper age group. The number of tests was calculated based on the "D Tests: Number of calculations by sex and age," and the "TARC (thymus and activation regulated chemokine)" as a specific marker among the five biomarkers for diagnosis and severity evaluation listed in the "Atopic Dermatitis Treatment Guidelines 2024" (hereinafter referred to as "Treatment Guidelines") ³⁾. TARC (thymus and activation regulated chemokine)" and "SCCA2 (squamous cell carcinoma antigen 2)" as specific markers among the five biomarkers for diagnosis and severity assessment listed in the "Clinical Practice Guidelines 2024 (hereafter referred to as "Clinical Practice Guidelines")3). Among the drug therapies listed in the medical practice guideline, topical agents were counted from "Topical agents_Quantity by sex and age by drug category Outpatient (in-hospital) (out-of-hospital)" to include topical steroids (excluding antibiotic/antimicrobial combination drugs and lotion formulations), "tacrolimus" as a new pharmacological topical agent, and "delgrolimus" as a new pharmacological agent. Monoclonal antibody drugs are included in the "Injection_Quantity by sex and age group, outpatient (in-hospital) and outpatient (out-of-hospital)". Dupilumab", "nemolizumab", and "tralokinumab" are included in the "Injection_Volume by Gender and Age". For oral Janus kinase (JAK) inhibitors, "baricitinib," "upadacitinib," and "abrocitinib" are included from "Oral_Outpatient_Quantity by Sex and Age Group (In-hospital) (Out-hospital)". abrocitinib" were counted.

As indicated in the medical guidelines, "topical steroids are the basic drugs for the treatment of atopic dermatitis (CQ1: Recommendation 1, Level of evidence: A), and the appropriate strength (rank) of steroid medication should be selected according to the severity of the individual skin rash" (Table 1). Here, the prescription volume of topical steroids of "Strong" rank or higher was tabulated to observe changes in the prescription volume of strong topical steroids with the launch of new pharmacologically active drugs such as JAK inhibitors and monoclonal antibody drugs. Note that topical steroids are also used to treat dermatitis and skin conditions other than atopic dermatitis, and since the NDBOD cannot confirm prescriptions tied to diseases, changes in prescription volume are only inferences. The reason for excluding antibiotic/antimicrobial combination drugs and lotion formulations was that the former were considered more likely to be prescribed for infectious skin diseases and the latter for dermatitis that develops on the scalp (e.g., seborrheic eczema). In addition, since most lotion formulations are prescribed in mL, the unit for expressing the transition of prescription unit volume is to be unified in g. As a note on new pharmacological agents, dupilumab was approved in April 2018 for "atopic dermatitis with inadequate response to existing therapy" in adults (15 years and older), and will be approved in March 2019 for "severe or refractory bronchial asthma with poor control" in patients 12 years and older and in September 2023 for "bronchial asthma" in patients 6 months old and older. The pediatric indication was expanded to "atopic dermatitis with inadequate response to existing therapies" in September 2023, and "idiopathic chronic urticaria with inadequate response to existing therapies" in February 2024 for patients aged 12 years and older, so the prescription unit dose will be the sum of these diseases. In March 2024, baricitinib's indications were expanded to include "atopic dermatitis with inadequate response to existing therapy" and "juvenile idiopathic arthritis with polyarticular activity" in patients aged 2 years and older.

The average annual percentage change (APC) of the estimated incidence rate was calculated as 100 × ((exp(m)-1)) using the calculation method shown in Reference ⁴⁾, in which the figures for each year were natural logarithmized to derive a linear regression line and the exponential value (exp(m)) of the coefficient (m).

The following are points to note about the NDBOD. (1) In the NDBOD, prescriptions are grouped by sex and by 5-year age group, and if the total number of prescriptions in each group is less than 1,000, it is indicated by "-" (if there is only one place where the number is less than 1,000, all minimum numbers above 1,000 are indicated by "-"), so the total number of prescriptions for age groups does not match the total. The total number of prescriptions for the top 100 drugs was listed until the 8th Survey, but since the top 100, top 300, and top 500 drugs were published thereafter, the 9th and 10th surveys were limited to the top 100 drugs in order to be consistent with previous data. However, for oral JAK inhibitors, the prescription unit volume for pediatric age groups began to appear in earnest from the 9th NDBOD (FY2022), and the top 100 items could not be fully tabulated; therefore, the top 300 items were included.

Results

(1) Incidence of atopic dermatitis

Figure 1 shows the trends in the estimated incidence rate of atopic dermatitis by school type and gender from the 2015-2024 School Health Statistics Survey.

Looking at the trends in incidence rates by urban class (Table 2), no significant changes were observed for both males and females, except for a large decrease for kindergarten students in "large cities" (APC; -6.6% for boys and -8.1% for girls) and an increase for junior high school girls in "towns and villages" (APC 2.7%). In addition, "large city" high school students showed a smaller annual increase than the total for both males and females (APC; 0.4% for males and 1.1% for females), while "small city" high school students showed an increase greater than the total (APC; 2.9% for males and 3.3% for females).

(2) Atopic dermatitis test

From the 2015-2023 NDBOD, the number of "TARC" and "SCCA2," which are specific tests for atopic dermatitis, were calculated in 5-year increments from 0 to 19 years of age, and the trends were examined by age group, The results are shown in Fig. 2. The APCs for the 0-4 age group were the highest, but the APCs for the 10-14 age group were 11.3% for boys and 11.2% for girls, and the APCs for the 15-19 age group were 12.9% for boys and 5.3% for girls. The APCs for the 10- to 14-year-old group were 11.3% for boys and 11.2% for girls, and for the 15- to 19-year-old group were 12.1% for boys and 10.2% for girls. The number of tests performed decreased with increasing age, but APCs increased significantly in the older age groups.

(3) Topical steroids

As before, Figure 3 shows the amount of topical steroid prescription units (kg) above the strong rank by age group and by sex.

These steroid prescription unit volumes are based on the aggregation of steroids in the top 100 brands of the NDBOD topical drug category name "analgesic, antipruritic, astringent, anti-inflammatory agents," but as indicated in the survey methodology notes, in the 9th (FY 2022) and 10th (FY 2023), the top 500 brands were tabulated. The remarkable increase in the unit volume of steroid prescriptions tabulated this time could be due to an increase in the aggregation of brands of steroids with the same ingredients for reasons of item liquidation or sales discontinuation, or a possible relative rank advancement of steroid brands due to the descent of other topical drugs to outside the top 100, and therefore, the outpatient out-of-hospital prescription within the above drug efficacy categories in the 2nd through 8th round of the NDB Since the minimum number of steroid brands above the Strong Rank for prescriptions was 13, we analyzed prescription unit volumes and APCs by fixing the total prescription unit volume to the top 13 brands for both in-hospital and outpatient use (Table 3). The total APC was 8.6%, No significant changes were observed for Strongest (APC for both Berry Strong and Strongest: 0.5% for boys and 0.6% for girls; no chart).

(4) Novel pharmacological agents

(1) Novel topical pharmacological agents

Figure 4 shows the different novel topical pharmacological agents "tacrolimus (TAC)" and "delgocitinib (JAK)" indicated for atopic dermatitis, The following table shows the trend of prescription unit volume of "tacrolimus (TAC)", "delgocitinib (JAK)" and "difamilast (PDE)". delgocitinib and difamilast both showed a clear increase since their launch, especially in younger age groups. However, the increase of tacrolimus has stagnated since the launch of the other two drugs.

(2) Antibody drugs

Figure 5 shows the results of prescriptions for the three antibody drugs "dupilumab," "nemolizumab," and "tralokinumab" indicated for the treatment of atopic dermatitis. The trends in the unit volume of prescriptions for the total of the three drugs are shown by gender. The majority of prescriptions were in the 15-19 age group for both genders, with a marked increase over time. As indicated by the aforementioned study methodology, dupilumab was approved for bronchial asthma for ages 12 years and older in March 2019 and for atopic dermatitis for ages 6 months and older in September 2023. Therefore, it is estimated that the prescription unit volume for the 10 years and older group after FY 2018 and the 5 years and older group in FY 2023 is primarily the sum of both diseases. nemolizumab is indicated only for "pruritus associated with atopic dermatitis" in patients 13 years and older, while tralokinumab is indicated for adults (15 years and older) "with existing treatments that are effective for The total prescription unit volume in FY2023 doubled from FY2022 for both males and females, with the ratio of male to female prescription unit volume being approximately 3:2 for the 10-14 year old group and 2:1 for the 15-19 year old group.

(iii) Internal JAK inhibitors

Table 4 shows the total number of prescriptions of "baricitinib," "upadacitinib," and "abrocitinib," three oral JAK inhibitors indicated for the treatment of atopic dermatitis, in FY2022-2023. "baricitinib," "upadacitinib," and "abrocitinib," a total of the three drugs, are shown below. As shown in the survey methodology, since the indication of baricitinib for atopic dermatitis in patients aged 2 years and older will be extended to March 2024, prescriptions of the three drugs for atopic dermatitis in the aggregate period will be either 12 years and older (upadacitinib and abrocitinib) or 15 years and older (baricitinib ), suggesting that most of the prescriptions were for atopic dermatitis. The ratio of male to female prescribing unit dose was approximately 3:2.

Summary and Discussion

(1) Incidence of atopic dermatitis

From the "Statistical Survey of School Health," we analyzed the incidence of atopic dermatitis by school type and gender for the 10-year period from FY 2015 to FY 2024. The incidence rate of kindergarten children showed a significant decrease, with an average annual decrease rate of more than 5% for both boys and girls. The incidence rate for elementary school students showed no significant change, although there was a negative trend, while the rates for junior high school girls, high school boys, and high school girls increased at an average annual rate of 2%.

According to the medical practice ^guideline3), an analysis of 14 articles on the prevalence of atopic dermatitis in Japan based on dermatologists' physical examinations from 1992 to 2002 showed that the prevalence by age ranged from 6 to 32% in infants, 5 to 27% in young children, 5 to 15% in school children, and 5 to 9% in university students, with a decreasing trend as the age ^{increased5) (5).} In the MHLW study conducted from 2000 to 2002, the prevalence rates obtained from a large-scale survey conducted by specialists at health centers and elementary school health checkups were 12.8% for 4-month-old children, 9.8% for 16-month-old children, 13.2% for 3-year-old children, 10.6% for 6th graders, and 8.2% for university ^students6). 6 ⁾ The prevalence rate for patients in urban areas, which has traditionally been considered high, was not significantly different from that in suburban areas in our ^survey7). 7 ⁾ As for annual changes, the prevalence of atopic dermatitis obtained from an allergic disease survey of elementary school children in western Japan decreased from 17.3% in 1992 to 13.8% in ²⁰⁰²⁸⁾. In contrast, a survey of 7- to 15-year-olds in Kyoto showed a slight increase in prevalence from 4.2% in 1996 to 5.6% in ²⁰⁰⁶⁹⁾. Thus, the prevalence data in the guidelines are from surveys conducted more than 20 years ago, indicating that there is a wide range of values from report to report.

It is controversial whether the prevalence and trends of atopic dermatitis among infants, children, and students in this survey have medical or medical-epidemiological value from a specialist's point of view. In particular, it is pointed out that the survey is not based on standardized diagnoses by medical specialists. However, each prefectural government uses this survey to grasp the health status and incidence rates of children in their municipalities, and uses it as basic data for policies to improve the health of infants, children, and students, and for school health administration.

(2) Atopic dermatitis test

The change in the incidence rate shown in this paper suggests a relationship with the change in the number of calculations of "TARC" and "SCCA2," which are specific tests for atopic dermatitis using the NDBOD. The average annual rate of change in the number of tests for the 0-4 age group was negative (-3.5% for boys and -2.1% for girls), but increased 5% for boys and girls in the 5-9 age group, 11% for boys and girls in the 10-14 age group, and 12% for boys and 10% for girls in the 15-19 age group. As shown in Appendix 2 at the end of this report, the number of children in Japan is declining year by year in all age groups, indicating a declining birthrate. The number of tests performed would be expected to decrease accordingly, but this was not the case, and the number of atopic dermatitis-specific tests increased in both the male and female groups aged 5 years and older. The number of calculated tests, especially in the older age group, increased by more than 10% per year, which may be causally related to the fact that the incidence rate increased by nearly 2% per year. The decrease in the number of visits for the 0-4 age group may have been due to a decrease in the number of visits ^. However, the decrease in the number of calculations for this age group began in 2018 and cannot be explained by the increase in the number of calculations for other age groups, so further analysis is needed.

(3) Topical steroids

The NDBOD analysis of the change in the number of prescriptions for topical steroids of strong rank or higher showed a large increase in all age groups. The results were unexpected, as we had hypothesized that the recent launch of new drugs with new pharmacological effects, such as antibody drugs and JAK inhibitors, which are considered to be game changers, would lead to a decrease in steroid use or an increase in the use of lower strength steroids. The results were unexpected, with a predominance of Strong's in the younger age group and Very Strong's in the older age group, and the large increase in Strong's in the older age group was particularly noteworthy. It is impossible to explain the reason for this marked increase solely in terms of the increase in atopic dermatitis incidence. Nor is it conceivable that the number of skin diseases for which topical steroids are indicated in young people is increasing rapidly. Initially, we thought that the number of brands ranked in the top 100 NDBOD "analgesics, antipruritics, astringents, and anti-inflammatory agents" or the volume of prescription units per brand had increased due to the consolidation of multiple steroid brands as a result of discontinuation or shipment adjustments, and we calculated the annual rate of change in prescription unit volume fixed at the top 13 brands, and this analysis also A large increase was observed.

Although details are not provided due to usage rules, we selected the most frequent standards for two representative components from the three steroid ranks using the IQVIA JPM data for verification purposes, and calculated the average annual rate of change from 2015 to 2023 for the six component volumes calculated from the annual ^sales11). The results showed that the total volume of the six ingredients increased at a rate of 3.5% per year, Strong's at 5.6% per year, Very Strong's at 3.7% per year, and Strongest's at 0.9% per year. Although this is only a simplified analysis with no consideration of age, the different databases showed that the use of topical steroids has been increasing in recent years. The increase in the use of topical steroids cannot be explained by changes in the number of patients with atopic dermatitis alone, but must be attributed to the efforts of physicians and other medical professionals to promote awareness of basic steroid treatment as indicated in medical guidelines, as well as to improved patient understanding of steroid treatment, the spread of disease awareness triggered by the launch of new pharmacologically active drugs, and the increase in the number of patients with atopic dermatitis. The increase in the number of prescriptions is thought to be due to multiple factors, including the spread of disease awareness, changes in prescribing patterns such as an increase in the volume of prescriptions per prescription triggered by a decrease in the opportunity to see a doctor due to coronas, and brand consolidation and shipment adjustments due to sales discontinuation and other factors. In particular, the increase in the use of topical steroids in the younger age group, despite a decrease in the prevalence of kindergarten children and no significant change in the prevalence of elementary school children, may be due to the fact that the "proactive therapy "3), in which topical steroids and other topical products for atopic dermatitis are administered intermittently as maintenance therapy after symptom remission in order to stabilize the symptoms, has been used to treat atopic dermatitis in the younger age group for many years. It is possible that "proactive therapy " ³⁾, in which topical steroids and other topical atopic dermatitis treatments are administered intermittently to stabilize symptoms after symptom remission, has become widespread in younger age groups, and that patients whose symptoms were masked in the School Health Statistics Survey may have escaped screening. In the presence of diverse real-world data with sufficient information, we look forward to the development of data utilization techniques that will lead to elaborate epidemiological studies showing the relationship between diseases, therapeutic agents, and treatment techniques, as NDB and other health and medical data are linked in order to promptly improve the accuracy of medical technology evaluation.

(4) Novel pharmacological agents

Atopic dermatitis treatment has undergone dramatic changes over the past several years. However, it took a long time for new therapeutic agents, which are expected to be game changers, to reach the market. According to clinical guidelines, topical steroids have been used in the treatment of atopic dermatitis for more than 60 years, and they are still a fundamental part of the treatment strategy ^.3) In 1993, the oral calcineurin inhibitor tacrolimus, which was launched as an anti-rejection agent in organ transplantation, was extended to various autoimmune diseases. In 1999, topical tacrolimus was launched for the treatment of atopic dermatitis. tacrolimus has shown efficacy in suppressing disease that is difficult to control with topical steroids, and has become a major weapon in the treatment of difficult-to-treat lesions, especially on the face and neck. Since the immunosuppressive mechanism of tacrolimus is completely different from that of steroids, the use of both drugs has made it possible in an increasing number of cases to reduce the amount of steroids. However, the development of new drugs to meet the unmet needs of atopic dermatitis patients has been required due to the limitations of efficacy, adverse events associated with long-term continuous use, and the inability to treat erosions and ulcers due to the risk of elevated blood levels ^.3) Even before tacrolimus, calcineurin inhibitors were used to prevent rejection of renal transplants. Although the calcineurin inhibitor cyclosporine, which had been used to suppress renal transplant rejection prior to tacrolimus, was extended to atopic dermatitis patients who were refractory to existing treatments in 2008, it took almost 20 years from the launch of topical tacrolimus until patients had access to a treatment with a new mechanism of action.

Table 5 shows the evolution of target molecules and approval ages of new pharmacologic agents: in 2018, the first antibody drug was approved for atopic dermatitis refractory to existing therapies; in 2020, the first topical JAK inhibitor was approved for atopic dermatitis; and from 2020 to 2021, three oral JAK inhibitors were approved for refractory to existing therapies. In 2022, a topical PDE4 inhibitor was approved, and in 2023-2024, three new antibody drugs were approved for treatment of refractory cases. Although many of these new drugs are strictly regulated for use by specialized centers and physicians under the "Guidelines for the Promotion of Optimal Use " ¹²⁾, the volume of prescriptions for new drugs is increasing significantly as indicated earlier. The new pharmacological action specifically inhibits the JAK-STAT signaling pathway by interleukins (ILs), which induces the Th2-type inflammatory response that is the main etiological factor, and the clinical effects (mainly improvement of itchiness and barrier function) that are expressed according to the molecule that acts have each been ^reported3), 3), it is thought that we are getting closer to the realization of "personalized medicine" that satisfies the unmet needs of each patient through specific pharmacological actions, not to mention the improvement of QOL such as itching and sleep disturbance, which are common problems of atopic dermatitis patients. At the same time, drugs with new pharmacological actions are characterized by adverse events such as serious infections, and clinicians have little accumulated information.

5. conclusion

Pediatric patients with atopic dermatitis suffer not only from symptoms, but also from various daily stresses that are considered to be a burden and strongly influence the change in symptoms. Parents are also expected to give special consideration to diet, environment, and medical expenses. The importance and value of pediatric care is increasing for Japanese society, which is facing an extremely low birthrate and aging population. Research-based pharmaceutical companies need to further engage in sustained innovation as part of their mission so that new therapeutic agents can fulfill the unmet needs of patients and their parents at a high level, improve quality of life, and realize well being. The active participation of patients and their guardians in the development of new drugs is an important factor in increasing the accuracy of the target product profile (TPP), which is the blueprint for the drug discovery concept. We believe that creating an environment in which outcome reports from patients, guardians, and caregivers are collected and evaluated in the practice, development, and daily life will be an essential element of Japan's future healthcare policy in order to continuously create innovative new drugs and to accurately evaluate the value of the new drugs that are created.

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