Clinical Trial Activity in Japan and Taiwan (2015-2025): Trends and Phase Distribution

Multi-regional clinical trials have become standard practice in modern drug development. Today, it is common for sponsors to include sites across North America, Europe, and the Asia-Pacific (APAC) region within a single global program.

While much of the recent attention on APAC has focused on rapid growth within China, Japan and Taiwan also notable locations for inclusion within global studies.

This article uses ClinicalTrial.Gov data to take a look at Phase 1-4 clinical trial activity in Japan and Taiwan from 2015 through 2025, assessing:

• How frequently trials are initiated in each country
• How activity is distributed across clinical phases
• Any notable trends in trial activity over the last decade

Note: All data used in this article were collected via ClinicalTrials.Gov in February 2026. Because registration practices vary by country and study type, this article best reflects trends in multinational pharmaceutical studies and should not be interpreted as a comprehensive count of all clinical research conducted within Japan or Taiwan.

Phase 1-4 Clinical Trials in Japan

Overall, clinical trial activity in Japan has remained relatively consistent over the past decade, according to data from ClinicalTrials.Gov. In total, there were nearly 9,000 trials within Japan (covering all categories – recruiting, completed, terminated, active – and including behavioral and device trials that are not assigned a Phase) registered in ClinicalTrials.Gov as of February 2026.

Of note:

• Between 2015 and 2025, the number of trials initiated each year in Japan has generally falls within a consistent range.
• Trial volume peaked in 2021, likely due to the industry-wide increase in active trials due to COVID-19.
• In the past, Japan’s regulations mandated a Phase 1 trial with healthy Japanese volunteers (J-Ph1) prior to participation in a multiregional trial. However, a new notification issued in December 2023 clarified that an additional J-Ph1 is not required unless deemed necessary. While there was a slight decrease in Phase 1 trials started in Japan from 2024 to 2025, it will be interesting to further assess how this updated regulation will impact the clinical trial landscape in Japan going forward.

Taiwan: Phase 1-4 Clinical Trials in ClinicalTrials.Gov

In total, there were over 12,000 trials within Taiwan (covering all categories – recruiting, completed, terminated, active – and including behavioral and device trials that are not assigned a Phase) registered in ClinicalTrials.Gov as of February 2026.

Of note:

• Taiwan’s lowest year of initiated registered trials was 2016 (approximately 225 Phase 1-4 trials)
• Since 2018, activity has been relatively stable with only modest year-to-year variation
• Phase 2/3 trials account for the largest share of activity, supporting the interpretation that Taiwan is most often included as part of a global program

Over the past decade, Japan and Taiwan have remained reliable participants in multinational clinical research.

Of course, translating this activity into operational decisions requires consideration of regulatory pathways, in-country representation requirements, study design strategy, and coordination across regions.