Points of View Trends in the Calculation of New Drugs, Focusing on Supplementary Drug Prices
-Trends before and after the NHI drug price reform in FY2024 (survey until August 2025) -Trends before and after the NHI drug price reform in FY2024 (survey until August 2025)

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Kumi Yoshino, Senior Researcher, Pharmaceutical and Industrial Policy Research Institute

SUMMARY

1. Introduction

NHI (National Health Insurance) drug prices for new drugs in Japan are determined based on the rules stipulated in the "Standards for Calculating NHI Drug Prices " ¹⁾. The NHI has been analyzing the impact of the NHI reform on the NHI drug price system, and has published several reports on this subject in the NHI News. ^{3, 4)} In No. 64, we analyzed the impact of the FY2018 NHI overhaul on NHI drug prices at the time of listing ^.3) And in No. 73, we examined the impact of the FY2012 NHI price reform on the NHI price for new drugs in Japan. ⁴⁾ In the following two reports, we examine the impact of the NHI price reform on the NHI price for new drugs in Japan. No.73, we tentatively analyzed and reported the impact of the FY2024 NHI drug price reforms on the prices of drugs at the time of entry into the market, mainly on the supplementary drug prices ^.4) However, the FY 2018 overhaul has not yet been fully implemented. However, unlike No. 64, which analyzed the FY2018 fundamental reform after a certain period of time had elapsed, No. 73, which surveyed before and after the FY2012 reform, was only a tentative analysis because only three drug prices were listed after the reform. This time, one year has passed since the last survey, and we have more data to analyze, so we decided to update the survey.

Survey Methodology

The survey was generally conducted in the same manner as in Policy Research Institute News No. ⁷³⁴⁾. Specifically, the survey was conducted using the same method as in Policy Research Institute News No. 73.4) Specifically, the survey was conducted on new active ingredients listed as new drugs from April 2018 to August 2025. For drugs containing new active ingredients listed as new drugs from April 2018 to August 2025, information on the drug price at the time of listing (drug price calculation method, correction additions, and additions for promotion of new drug creation and resolution of off-label drug use (hereinafter referred to as "new drug creation additions")) was obtained from the Central Social Insurance Medical Council's (hereinafter referred to as "Chuikyo") "New Drug List " ^{5) and other sources}. The same ingredient and the same dosage form were analyzed as a single product.

The data collection method was changed from No. 73 regarding the applicability of the additional fee for new drug creation, etc. In No. 73, the analysis was based on the descriptions in the Chuikyo documents as with other additional fee systems, but the additional fee for new drug creation, etc. at the time of listing was not included in the Chuikyo documents until after listing in August 2018 ^.6) The data collection method was also changed from No. 73, 6 ⁾ However, since the addition of new drug creation, etc. at the time of listing was not listed in the Chuikyo materials until August 20186) , it was determined that a survey based solely on the Chuikyo materials would not be able to compile all the data.

The NHI drug price system is reformed every two years, and various changes are made each time, but in FY2018, there was a particularly large review as a fundamental reform, with significant changes in the supplementary drug price and the additional drug price for the creation of new ^drugs3). In particular, there were major systemic changes in the supplemental cost and the supplemental cost for new drug creation, etc.3). The period covered by No. 73 was from April 2018 to August 2024. Since the purpose of this report is to update the survey of No. 73, the survey period was set to April 2018 onward, as in the previous survey, and two accessions in FY2024 (November 2024 and March 2025) and four accessions in FY2025 (April, May, July, and August) that were included since the previous survey were added to the scope. The reason for one more listing in this report (FY2025) than in No.73 (FY2024) for the latest year is that the timing of new drug approvals has increased from four to seven times per ^{year9, 10)} due to the increased timing of new drug approvals.

Although the current survey added data for the most recent year since the previous survey, only one year and five months (69 drugs containing new active ingredients) were listed after the FY2024 system reform, and compared to the data before the system reform (243 drugs containing new active ingredients listed in FY 2018-2023), both the period and number of The number of new active ingredient-containing drugs is small. Therefore, it should be presented in advance that this report is a survey and analysis of the impact of the FY2024 NHI drug price reform on the calculation status centered on the supplemental fee, based on data as of August 2025.

2-1. Calculation Method

The calculation methods applicable to drugs containing new active ingredients are mainly the comparable drug effect method and the cost accounting ^method4). There are (I) and (II) similar drug effect comparison methods, Therefore, the analysis after the addition of the correction was limited to the similar drug effect comparison method (I) and the cost accounting method.

2-2. Additional fee for correction

The supplemental cost increases that may be applicable to drugs containing new active ingredients when they are listed on the market are the additions to the usefulness system (additions to the breakthrough system, additions to the usefulness system (I), and additions to the usefulness system (II)), which evaluate innovation and usefulness in terms of efficacy, safety, etc., and the additions to the market for drugs that are small but highly necessary in terms of medical care (additions to the marketability system (I), additions to the marketability system (II), and additions to the marketability system (III), IV). ), Additional Marketability Payment (II), Additional Special Use Payment, Additional Pediatric Payment), and an additional payment to incentivize early launch of drugs in Japan (Additional Pioneer Payment, Additional Expedited Introduction Payment). Specifically, the NHI drug price reform in FY2024 made a number of changes, including the addition of additional requirements to the Additional Fee for Utility, which is an additional fee to evaluate the usefulness of drugs, the flexible use of the additional fee for marketability and pediatric drugs, the establishment of the Additional Fee for Expedited Introduction as an incentive for early introduction of new drugs into Japan, and the addition of new drugs to be covered under the Additional Fee for New Drug Creation, a system to maintain the drug price after listing on the market4) . ^4). This report is an update of No. 73, a survey on the impact of these system changes.

Results

3-1. Current Status of Calculation Method

(1) Ratio of calculation method (drugs containing new active ingredients)

Regarding the calculation methods used for drugs containing new active ingredients listed in FY 2018-2025 (April, May, July, and August for FY 2025), we surveyed the number of drugs and their ratios in the comparable drug effect method (I) and the cost accounting method. The results showed that although there were some fluctuations from year to year, in recent years, the similar drug effect comparison method (I) accounted for 60-70% and the cost accounting method for 20-30% (Figure 1). The trend was similar to the previous year. The number of similar drugs (II) was at least 3 per year until FY2021, but has been decreasing in recent years.

(2) Ratio of calculation method (by dosage form)

By mode of administration, the ratio of the cost accounting method has tended to be the same or higher for injectable drugs than for oral drugs, but by FY2025 (by the August listing), the similar drug effect comparison method (I) will account for 50% (4/8) and the cost accounting method 38% (3/8) for oral drugs, and for injectable drugs, the similar drug effect comparison method (I) will account for 88% (7/8) and the cost accounting method For injectable drugs, the similar drug effect comparison method (I) accounted for 88% (7/8) and the cost accounting method for 13% (1/8), indicating that the ratio of the cost accounting method was higher for drugs for internal use. As it is still midway through the fiscal year and the number of products is still small, future trends need to be monitored closely.

3-2. Current Status of Additional Calculation Methods

(1) Current status of additional fee for usefulness

Regarding the addition to the usefulness system, we first examined the applicable status of the addition to the usefulness system: for drugs containing new active ingredients listed in FY 2018 and later, we surveyed the percentage of drugs that fell under the addition to the usefulness system, the addition to the usefulness system (I), and the addition to the usefulness system (II) by calculation method using the similar drug effect comparison method (I) and the cost accounting method. As a result, the percentage of drugs that were added to the usefulness system was 42% (64/153) in FY 2018-2023 for the similar drug effect comparison method (I), 55% (26/47) in FY 2024 and later (until August listing in 2025), and 70% (49/70) in FY 2018-2023 for the cost accounting method, and 70% (49/70) in FY 2024 and later (August listing in 2025) for the similar drug effect comparison method (II). Compared to the situation in April-August 2024 analyzed in No. 73 (similar drug efficacy comparison method (I): 70% (14/20), cost accounting method: 100% (10/10)), the usefulness system from April 2024 to August 2025 analyzed in this study was 55% (26/47) in FY24 and after (until August in 2025), while it was 70% (49/70) in FY 2018-2023 in the cost accounting method (Figure 2 pie chart). However, the increase in the percentage of cases falling under the usefulness-based addition was observed before and after the 2024 NHI drug price reform, which was similar to No. 73. Also, the change in the percentage of cases falling under the additional fee for usefulness (I) was significant for all calculation methods (similar drug effect comparison method (I): 7% (11/153) to 19% (9/47); cost accounting method: 14% (10/70) to 40% (8/20); Figure 2 pie chart), similar to No.73 ^.4).

When the annual trend was checked, compared to No.73, which was analyzed in the middle of the fiscal year, the applicable ratio to the usefulness system addition decreased significantly in FY2024, mainly in the similar drug effect comparison method (I) (FY2024 April to August (14/20): ^70%4) and FY2024 annual: 53% (19/36) (Figure 2 bar graph)).

On the other hand, as of August, FY2025 had the highest percentage for all calculation methods during the survey period (Figure 2 bar graph, Comparable drug effect comparison method (I): 64%, cost accounting method: 100%). The next section discusses the additional cost of usefulness-based drugs.

Next, we examined the addition rate for the addition of usefulness-based products. The average addition rate for the usefulness-based additions was 18.3%, 20.0%, and 31.4% in FY 2018, 2024, and 2025, respectively, which were slightly higher than in the other years, and FY 2025 showed the highest rate in the survey period (Figure 3). (Figure 3). However, the trend of the addition rate throughout the year in FY2025 is considered to be dependent on future trends.

(2) Additional fee for marketability, additional fee for pediatric patients

Next, we examined the marketability additions and the pediatric additions. The percentage of drugs falling under either the Marketability Additions ((I) or (II)) or the Pediatric Additions was surveyed for drugs containing new active ingredients that were listed in FY 2018 or later. As a result, the percentage was 16% (24/153) in FY 2018-2023 for the similar drug efficacy comparison method (I), but 28% (13/47) in FY 2024 and thereafter (until August listing in 2025), and 59% (41/70) in FY 2018-2023 for the cost accounting method (I), but 59% (41/70) in FY 2024 and thereafter ( The overall increase trend before and after the NHI price reform in 2024 was similar to that of No.73, but the situation from April to August 2024 analyzed in No.73 (similar drug effect comparison method (I): 45% (9/20), cost accounting method: 70% (7/20)) was different from that of No.73 (similar drug effect comparison method (I): 45% (9/20), cost accounting method: 70% (7/20)). However, compared to the situation from April to August 2024 analyzed in No. 73 (similar drug effect comparison method (I): 45% (9/20), cost accounting method: 70% (7/10)), the applicable rate was lower for the similar drug effect comparison method (I) from April 2024 to August 2025 analyzed in this ^report4). However, when looking at the individual additions, the percentage of marketability additions (I) in the similar drug effect comparison method (I) was lower from April 2024 to August 2025 than in the similar drug effect comparison method (I) from April to August 2024 to August 2025.4 ⁾ The percentage of marketability addition (I) in the similar drug effect comparison method (I) was 10% (2/20) in April-August 2024 and 11% (5/47) from April 2024 to August 2025 (Fig. 4), while the percentage of pediatric addition was 35% (7/20) in April-August 2024 and 17% (8/47) from April 2024 to August 2025 (Fig. 4), showing a difference. A difference was observed.

Furthermore, we examined the addition rate of the addition for marketability and the addition for pediatric patients: we examined the average rate of the addition for marketability (I) and the addition for pediatric patients for drugs containing new active ingredients calculated by the similar drug effect comparison method (I) or cost accounting method after FY 2018, and found that the rate for marketability (I) had consistently remained 10 The results of the survey showed that the average rates of additions to the marketability index (I) and the additions to the pediatric index were 11.1% and 13.3%, respectively, in FY2024 and FY2025, the first time the rates exceeded 10% (Figure 5, top). In FY2024, the average value of the addition for pediatric patients was 10%, while in FY2025 it was 5%, but we refrain from discussing the trend since only one product was added in FY2025. For the survey on the addition to the pediatric drug benefit scheme, including drugs other than those containing new active ingredients and those added at the time of revision, please refer to Policy Research Institute News No. 75, along with the status of ^approval12).

(3) Additional fee for new drug creation, etc.

The survey was conducted on the percentage of drugs that were subject to the additional payment for new drug creation, etc. for drugs containing new active ingredients that were calculated based on the similar drug effect comparison method (I) or cost accounting method in FY 2018 or later. As with No. 73, a comparison was made for each reform (every two years), since the requirements for the Additional Allowance for New Drug Creation, etc., have been added for each reform. As a result, the percentage of the items covered by the "Additional Drug Value Added" was 62% (32/52), 56% (24/43), 64% (37/58), and 79% (37/47) for the "Comparable Drug Value" method (I), and 89% (16/18), 59% (16/27), 76% (19/25), and 95% (19/20) for the cost accounting method, showing that the percentage of the items covered by the "Additional Drug Value Added" method was the highest after the fiscal 2024 NHI price reforms for all calculation methods. The highest percentages were obtained after the reform of the NHI drug price system in FY2024 for all calculation methods (Figure 6 pie chart). On the other hand, looking at annual trends, the percentage for all calculation methods consistently exceeded 70% from FY2023 onward, although there was a large year-to-year variation in the cost accounting method, which has a small number of cases (Figure 6 bar graph).

3-3. Analysis of the Impact of the System Change on the Additional Calculation

The results of the survey in the previous section, 3-2. Current status of supplemental payments, etc., compared before and after the system reform, do not allow a general analysis of the impact of the system alone, since the target drugs themselves differ. Therefore, for the purpose of analysis focusing more on the impact of the system, the survey was limited to items that were newly established or expanded under the FY2024 NHI drug price reform.

(1) Applicability to newly established/expanded items

First, we examined the applicability of the newly established/expanded requirements for each category, i.e., additional fee for usefulness, additional fee for marketability/additional fee for pediatric patients, additional fee for rapid introduction, and additional fee for new drug creation, etc. (Table 1).

As for the newly established/expanded requirements for the Additional Indications for New Drug Creation, No. 73 reported cases of (1) - d (different drug discovery and manufacturing process), (1) - e (no new drug with a new mechanism of action listed for a long period in the target therapeutic area) and (3) - f (improvement in important secondary endpoints) ⁴⁾, but in FY2025, (3) - e (improvement in a specific population based on a new mechanism of action) was added to (1) - f (improvement in an important secondary endpoint). (Effect in a specific population based on the mechanism of action) in FY2025. This means that if we include (2)-2-b, which may have been applicable to two products, ¹³⁾ we can consider that all the expanded requirements are now applicable to all the products.

The number of cases falling under the "flexible operation of the addition rate" introduced for the addition of marketability/pediatric drugs increased steadily from the latter half of FY2024 onward, with 7 out of 20 (35.0%) of the additions for marketability (I).

In addition, the number of items falling under the additional fee for expedited introduction, which was newly established under the FY2024 NHI drug price reform, increased by 2 items in the second half of FY2024, bringing the total to 4 items, but there were no applicable cases as of August in FY2025.

As for the additional fee for creation of new drugs, five out of 56 (8.9%) products (pediatric requirement: 4 products, composition efficacy product sales identical: 1 product) met the introduced requirements at the present time.

(2) Impact of system changes on items falling under newly established/expanded categories

The impact of the change on "applicability" and "addition rate" for these items (including the two items in parentheses) summarized in Table 1 was then examined.

First, as an impact on the "applicability of additions," we investigated whether there were any items that did not fall under additions under the previous system but became newly eligible for additions as a result of the reform. As for the "additions to the usefulness system," there was one item that was assumed to have been changed from "addition to the usefulness system (II)" to "addition to the usefulness system (I)" and two items that were assumed to have been changed from "addition to the usefulness system (I)" to "addition to the usefulness system (I)," but there were no items that were assumed to have been not applicable to any of the "addition to the usefulness system" under the previous ^system14). The following is a summary of the results of the analysis. Therefore, it can be said that the system reform contributed to the expansion of the applicable rate for each of the usefulness additions (I) and the breakthrough additions, but did not have the effect of expanding the applicable rate for the entire usefulness additions during the period studied in this paper. In other words, the main reason for the change in the rate of additions to the usefulness index (Figure 2) observed before and after the system change (before and after FY2023 and after FY2024) and during the annual transition (from FY2023 to FY2024 and FY2025) is not the system change. The impact on the applicability of the additional fee for marketability (I) and the additional fee for pediatric care was not examined, since the change in the system itself was "flexible operation of the additional fee rate". In addition, as for the additional fee for expedited introduction, it can be said that all of the four applicable items contributed not only to the rate of addition but also to the applicable rate. On the other hand, the impact on the applicability of the expanded requirements for the additional payment for new drug creation, etc. was not considered, since it was difficult to judge individually whether or not a drug was eligible for the additional payment for new drug creation, etc. even under the existing system (or whether or not it could not be eligible under requirements other than those that were expanded).

Next, for the purpose of examining the impact of the system change on the "addition ratio," the addition ratios for the items summarized in Table 1 (including the two items in parentheses) were estimated "if the system change had not been implemented" and compared with the actual addition ratios. The impact of the reform on the addition ratio for the usefulness-based addition, marketability-based addition (I), and rapid introduction addition was evaluated, and the average value of the addition ratio increased by 5 to 10 points or more due to the reform (Table 2). The average rate of addition to the list of 9 useful items increased from an average of 28.3% before the reform to 42.8% after the reform, an increase of 14.5 percentage points on ^{average15, 16, 17)}. The impact was estimated to be an increase of 2.9 percentage points (14.5% x 9 items ÷ 45 items = 2.9%). According to Figure 3, the average addition rate for usefulness-based additions was 20.0% in FY2024 and 31.4% in the first half of FY2025 (up 2.7 and 14.1 points, respectively, from FY2023), compared to 17.3% in FY2023, and when calculated as the average of 45 items in FY2024 and beyond, the average addition rate was 22.8% (5.9% compared to FY2023). The average addition rate for the 45 items after FY2024 was 22.8% (an increase of 5.5 percentage points from FY2023). This suggests that the actual change in the average addition ratio may be somewhat larger than the impact on the average addition ratio (2.9 percentage point increase in the average value) due to the system change estimated in this report. On the other hand, the average rate of addition to the marketability index (I), which was 10% before the reform, increased to 15% after the reform, an increase of 5 points on average for the seven items. The impact on the average rate of addition (I) for the 20 items that qualified for addition (I) was 1.8 percentage points (5.0% x 7 items / 20 items = 1.8%). Figure 5 shows that the average addition rate for marketability addition (I) was 11.1% in FY2024 and 13.3% in the first half of FY2025 (up 1.1 and 3.3 points, respectively, from FY2023), compared to 10% in FY2023, and when calculated as the average of 20 items in FY2024 and beyond, the average addition rate was 11.8% (up 1.8 points from FY2023). This is an increase of 1.8 percentage points from FY2023. In other words, the impact of the system change on the average addition ratio (1.8 percentage point increase in the average value) is the same as the impact of the system change estimated in this report.

The pediatric additions were not included in this study because it was particularly difficult to assume the "addition rate if the requirements had not been expanded.

Summary and Discussion

This report examines the calculation status, mainly the supplemental fee, for drugs containing new active ingredients listed from April 2018 to August 2025. The calculation method used consistently varied slightly from year to year, but the similar drug effect comparison method (I) was used most frequently. In recent years, the similar drug effect comparison method (I) accounted for 60-70%, and the cost accounting method for 20-30% (Figure 1). The number of similar drug effect comparison method (II) has been decreasing in recent years, and has been 0 to 1 since FY2023 (as of August for FY2025, Table 3). This may indicate the possibility of an increase in the development of innovative new drugs.

By mode of administration, the ratio of cost accounting method has tended to be higher for injectable drugs than for oral drugs, but in FY2025 (up to August listing), the ratio of cost accounting method was higher for oral drugs than for injectable drugs. Since it is still in the middle of the fiscal year and the number of items is still small, the trend throughout the year will depend on future trends, but in FY2025, the three items for which the cost accounting method was used for internal use were all orphan drugs. Orphan drugs are considered to have few similar drugs due to their designation ^{requirements18)} and may be more likely to be calculated using the cost accounting method. In fact, a higher percentage of orphan drugs listed in FY2018 and later were calculated using the cost accounting method compared to other drugs (Figure 7). The reason why the ratio of cost accounting method has been higher for injectable drugs in the past was considered to be the large number of new modalities, etc. However, if the development of drugs for intractable or rare diseases increases even with existing modalities for internal use, it may be difficult to decrease the ratio of cost accounting method under the current drug price system.

As with the results of survey No.73, there was a trend of an increase in the ratio of various supplementary fees in FY2024 and later compared to FY2023 and earlier (Figures 2, 4, and 6), but in FY2024, many items showed a decrease in value compared to the previous report. In particular, the percentage of respondents who applied for the "additional fee for usefulness" and the "additional fee for pediatric patients" under the similar drug effect comparison method (I) decreased in this annual survey compared to the previous survey conducted in the middle of the fiscal year. This is thought to be due to the fact that there was a difference in the percentage of applicable claims for the additional fee for usefulness and the additional fee for pediatric use in the similar drug effect comparison method (I) between the first half and the latter half of FY2024 (Table 4). However, in light of the trends in FY2024, it is difficult to examine the trends for the entire year at this point, and it is necessary to continue to monitor trends after the NHI price reform in FY2024.

Although it is difficult to make a time-series comparison before and after the changes to the system, since the target drugs themselves differ, it is difficult to consider the impact of the system alone, but there has been a steady increase in the number of cases that correspond to the changes in the 2024 NHI drug price reform, including the newly established additional fee for usefulness, additional fee for new drug creation, and "flexible use of additional fee rates" (Table 1). One item (3)-e, which was not included in the previous survey, was also included, indicating that all cases are now included (Table 1). The above indicates that the reformed system is being applied continuously. The reform of the additional fee for usefulness was found to have an impact on the fee rate for items that met the newly established/expanded requirements, suggesting that the value of innovation in pharmaceutical products may have been evaluated more multilaterally as a result of the reform of the system. On the other hand, the expansion of the applicable rate for the additional fee based on the newly established/expanded requirements for the additional fee for usefulness did not occur at the time of this survey. Nevertheless, the fact that the percentage of drugs that qualify for the additional utility-based payment has increased since FY2024 compared to FY2023 and before suggests that, in addition to the enhancement of the evaluation of drug value through system reform, the number of drugs that should be evaluated has increased as well.

Conclusion

This report updates the status of NHI drug price calculation for drugs containing new active ingredients from the latter half of FY2024 onward, with a focus on the supplementary fee. As a result, as in the previous report, it appears that the system that was changed to evaluate innovation in the FY2024 NHI drug price reform continues to be applied. On the other hand, since there was a difference in the trend of applicable ratios for some of the supplemental payments in the first half and the second half of FY2024, the annual trend for FY2025 should also be determined based on future trends. Since the supplemental spending supplement is affected by both the creation of innovative drugs and the appropriate evaluation of drugs, it is difficult to make generalizations regarding the increase or decrease in the applicable ratio at any one point in time. However, it is possible that the system could provide important information for realizing a virtuous cycle of appropriate evaluation of innovation and sustainable creation of innovative new drugs, including an analysis of the relationship between the requirements for application of the system and the addition to the system using micro data, as attempted in this paper. We look forward to the continued transparent disclosure of information in the future.

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