[6-K] Takeda Pharmaceutical Company Limited American Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Takeda reported positive Phase 3 results for oveporexton (TAK-861), an oral OX2R-selective agonist for narcolepsy type 1 (NT1). Two global, double-blind, placebo-controlled studies (FirstLight and RadiantLight) met all primary and secondary endpoints at week 12 with p-values <0.001 across doses (twice-daily 1mg and 2mg), showing statistically significant improvement in wakefulness, excessive daytime sleepiness, cataplexy frequency, symptom severity and quality of life.

The 12-week program enrolled 273 patients across 19 countries; more than 95% of completers entered the ongoing long-term extension. Oveporexton was generally well tolerated with no treatment-related serious adverse events reported; the most common adverse events were insomnia and urinary urgency/frequency. Takeda said these Phase 3 results do not have a significant impact on its consolidated forecast for the fiscal year ending March 31, 2026.

Positive

• Both Phase 3 studies met all primary and secondary endpoints with p-values <0.001 across doses.
• Broad symptomatic benefit reported: improvements in wakefulness (MWT), ESS, weekly cataplexy rate, symptom severity (NSS-CT) and quality of life (SF-36, EQ-5D-5L).
• Large, global program: 273 patients across 19 countries with >95% of completers enrolling in the long-term extension.
• No treatment-related serious adverse events reported and safety profile consistent with prior studies.
• Regulatory progress: Breakthrough Therapy designation from FDA and China NMPA for excessive daytime sleepiness in NT1.

Negative

• Adverse events observed: most common were insomnia and urinary urgency/frequency (mostly mild to moderate).
• No significant impact on FY2026 forecast reported, indicating limited near-term financial effect from these results.

Insights

Financial Analyst

TL;DR: Positive clinical readout but limited near-term financial effect on FY2026 guidance.

From a capital-markets perspective, two pivotal Phase 3 trials meeting all primary and secondary endpoints with p<0.001 is a strong clinical de-risking event that increases the probability of regulatory submissions and future commercial value. The program size (273 patients across 19 countries) and high LTE enrollment support durability and retention. However, Takeda explicitly stated no significant impact on FY2026 consolidated forecast, indicating expected near-term revenue or expense changes are not material to current guidance. Investors should view this as a material clinical milestone with potential medium-term value creation rather than an immediate financial catalyst.

Clinical Development Expert

TL;DR: Robust Phase 3 efficacy and tolerability data support oveporexton as a potential first-in-class oral orexin therapy for NT1.

The trials demonstrated clinically meaningful improvements across wakefulness (MWT), subjective sleepiness (ESS), weekly cataplexy rate (median percent change >80%), symptom severity (NSS-CT) and quality-of-life measures (SF-36, EQ-5D-5L). The majority on 2/2mg reached normative MWT and ESS thresholds, and nearly all treated participants reported improvement on PGI-C. Safety was consistent with prior studies and no treatment-related serious adverse events were observed. Combined with Breakthrough Therapy designations, these data support advancing global regulatory submissions and long-term evaluation.

FORM 6-K

U.S. SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of September 2025

Commission File Number: 001-38757

TAKEDA PHARMACEUTICAL COMPANY LIMITED

(Translation of registrant’s name into English)

1-1, Nihonbashi-Honcho 2-Chome

Chuo-ku, Tokyo 103-8668

Japan

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  ☒            Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

Information furnished on this form:

EXHIBIT

Exhibit Number
1						Takeda Presents Orexin Data from Landmark Oveporexton (TAK-861) Phase 3 Program in Narcolepsy Type 1 at World Sleep 2025
99.1						Takeda’s Leading Orexin Franchise Oveporexton Phase 3 Data & Commercial Readiness

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

						TAKEDA PHARMACEUTICAL COMPANY LIMITED
Date: September 8, 2025						By:			/s/ Norimasa Takeda
									Norimasa Takeda Chief Accounting Officer and Corporate Controller

Takeda Presents Orexin Data from Landmark Oveporexton (TAK-861) Phase 3 Program in Narcolepsy Type 1 at World Sleep 2025

SINGAPORE, OSAKA, Japan and CAMBRIDGE, Massachusetts, September 8, 2025 – Takeda (TSE:4502/NYSE:TAK) will present data from two global Phase 3 double-blind, placebo-controlled studies of oveporexton (TAK-861), a potential first-in-class investigational oral orexin receptor 2 (OX2R)-selective agonist in narcolepsy type 1 (NT1), during multiple oral presentations at the World Sleep 2025 Congress in Singapore beginning at 3:15 p.m. SGT today. Please refer to the attached press release and presentation for details.

The topline results of these studies were disclosed on July 14, 2025 in, “Takeda Announces Positive Results from Two Pivotal Phase 3 Studies of Oveporexton (TAK-861) in Narcolepsy Type 1”.

Media Contact:			Investor Contact:
Rachel Wallace rachel.wallace2@takeda.com			Christopher O’Reilly christopher.oreilly@takeda.com

Results from these studies have no significant impact on the full year consolidated forecast for the fiscal year ending March 31, 2026.

###

Takeda Presents Orexin Data from Landmark Oveporexton (TAK-861) Phase 3 Program in Narcolepsy Type 1 at World Sleep 2025

–Takeda is the Leader in Orexin Science and is on Track to Submit Global Regulatory Applications Starting in Fiscal Year 2025

–Four Orexin Oral Presentations from Phase 3 Pivotal Studies Highlight Statistically Significant and Clinically Meaningful Improvement in Narcolepsy Type 1 Symptoms Demonstrating the Potential for a New Era of Care

–Oveporexton was Generally Well-Tolerated with Safety Profile Consistent with Previous Clinical Studies

SINGAPORE, OSAKA, Japan and CAMBRIDGE, Massachusetts, September 8, 2025 – Takeda (TSE:4502/NYSE:TAK) will present data from two global Phase 3 double-blind, placebo-controlled studies of oveporexton (TAK-861)1, a potential first-in-class investigational oral orexin receptor 2 (OX2R)-selective agonist in narcolepsy type 1 (NT1), during multiple oral presentations at the World Sleep 2025 Congress in Singapore beginning at 3:15 p.m. SGT today.

Both the FirstLight (TAK-861-3001) and RadiantLight (TAK-861-3002) studies met all primary and secondary endpoints demonstrating statistically significant improvement across a broad range of NT1 symptoms compared to placebo with p-values of <0.001 across all doses (twice-daily 1mg/twice-daily 2mg) at week 12. Oveporexton was generally well-tolerated with a safety profile consistent across clinical studies to date. No serious treatment-related adverse events were reported. The most common adverse events were insomnia, urinary urgency and frequency.

NT1 is a chronic, rare neurological disease caused by the loss of orexin neurons in the brain that results in a range of debilitating symptoms, which can severely impact every aspect of life. Currently, the standard available therapies only partially address some of the symptoms people face. As an orexin agonist, oveporexton is designed to fully address a broad range of NT1 symptoms by targeting the underlying orexin deficiency.

“Our research has shown that the loss of orexin is the cause of narcolepsy type 1, which results in symptoms like excessive daytime sleepiness and cataplexy,” said Dr. Emmanuel Mignot, M.D., Ph.D., principal investigator for the FirstLight Phase 3 study and one of the presenting authors. “Takeda’s groundbreaking efforts targeting the orexin receptor 2 in clinical studies led to positive Phase 3 results for oveporexton, bringing us a major step closer to having the first orexin therapy that addresses the underlying cause of narcolepsy type 1—with the potential of transforming the current treatment paradigm.”

Oveporexton was discovered in our Takeda labs. The Phase 3 oveporexton program is one of the largest, most comprehensive development programs for NT1. The studies investigated 14 primary and secondary endpoints over a total of 12 weeks in 273 patients across 19 countries. More than 95 percent of the participants who completed the studies enrolled in the ongoing long-term extension (LTE) study.

The oral presentations at World Sleep include data from objective and patient-reported measures of wakefulness, cataplexy, symptom severity and quality of life, including2,3,4,5:

•Wakefulness: Oveporexton improved excessive daytime sleepiness demonstrating statistically significant improvement from baseline in mean sleep latency on the Maintenance of Wakefulness Test (MWT) and in Epworth Sleepiness Scale (ESS) scores at week 12 across doses compared to placebo. The majority of participants treated with the 2/2mg dose achieved wakefulness within normative range (≥20 min) on the MWT, and close to 85 percent of participants achieved ESS scores comparable to healthy individuals (≤10).

•Cataplexy: Oveporexton demonstrated significant reduction in weekly cataplexy rate over 12 weeks across doses compared to placebo (median of percent change from baseline more than 80%). Median cataplexy free days compared to placebo improved from 0 days at baseline to 4-5 days per week at week 12. Cataplexy is a defining symptom for NT1 and is the sudden loss of muscle tone triggered by strong emotions.

•Symptom Severity: Oveporexton showed statistically significant changes from baseline in the narcolepsy severity scale (NSS-CT) total score compared to placebo with more than 70 percent of participants reporting the lowest severity level (mild; score 0-14) across doses. Oveporexton also resulted in statistically significant improvements in overall narcolepsy symptoms as assessed by the self-rated Patient Global Impression of Change (PGI-C) scale with nearly all treated participants (97%) reporting improvements.

•Quality of Life: Oveporexton resulted in statistically significant improvements in quality of life reaching scores in the normative range as assessed by the Short Form-36-item (SF-36) survey. These outcomes were supported by significant improvements on exploratory endpoints including the EuroQol 5-Dimension 5-Level (EQ-5D-5L).

•Safety Profile: Across both studies, oveporexton was generally well-tolerated. No treatment-related serious adverse events were observed. Consistent with our experience from previous clinical studies, the most common adverse events were insomnia, urinary urgency and frequency. Most adverse events were mild to moderate.

“We are leveraging our leadership in orexin science and development with the aim to bring oveporexton to patients expeditiously in partnership with health authorities,” said Sarah Sheikh, M.Sc., B.M., B.Ch., MRCP, Head, Neuroscience Therapeutic Area Unit and Global Development at Takeda. “We are excited to share these transformative results at World Sleep, which demonstrate the potential for a new era of care defined by multiple treatment measures that matter to patients.”

Takeda will share other presentations during the World Sleep Congress in oral and poster sessions, including the impact of stigma on people with NT1, evaluations of sleep algorithms and orexin biomarkers for more accurate NT1 diagnosis and additional analyses from the oveporexton Phase 2b study, including patient satisfaction with treatment survey and impact on cognition, microsleeps and napping.

Results from the Phase 3 studies have no significant impact on the full year consolidated forecast for the fiscal year ending March 31, 2026.

Takeda Investor Conference Call and Webcast Details

Takeda will host an investor call to discuss the Phase 3 data and market opportunity for oveporexton today, September 8, at 7:30-8:45 p.m. SGT/7:30-8:45 a.m. EDT (8:30-9:45 p.m. JST). Presentation slides and a virtual meeting registration link are now available here. An on-demand replay of the webcast will be made available on Takeda’s website after the conclusion of the event. 

About Oveporexton (TAK-861)

Oveporexton (TAK-861) is an investigational orexin receptor 2 (OX2R)-selective agonist, which selectively stimulates the OX2R to restore signaling and address the underlying orexin deficiency that causes narcolepsy type 1 (NT1). By activating OX2Rs, oveporexton is designed to promote wakefulness and reduce abnormal rapid eye movement (REM)-sleep like phenomena, including cataplexy, to address the broad spectrum of daytime and nighttime symptoms.

About the FirstLight and RadiantLight Phase 3 Orexin Studies

FirstLight (TAK-861-3001; NCT06470828) and RadiantLight (TAK-861-3002; NCT06505031) are global, multicenter, placebo-controlled studies to evaluate the efficacy, safety and tolerability of oveporexton compared to placebo in patients with narcolepsy type 1 (NT1) over 12 weeks. The studies were conducted in 19 countries with enrollment completed within six months. The FirstLight study enrolled 168 participants randomized to one of three dosing arms (twice-daily 2mg, 1mg and placebo). The RadiantLight study enrolled 105 participants randomized to two dosing arms (twice-daily 2mg and placebo). The primary endpoint in both studies was improvement in excessive daytime sleepiness (EDS) as measured by the Maintenance of Wakefulness Test (MWT), a standard measure of wakefulness. Key secondary endpoints included improvement in EDS as measured by the Epworth Sleepiness Scale (ESS) and in the Weekly Cataplexy Rate (WCR), a measure evaluating cataplexy. The studies also evaluated the effect of oveporexton on participants' ability to maintain attention, participants’ overall quality of life, the spectrum of narcolepsy symptoms and daily life functions, as well as the safety and tolerability of oveporexton.

About Takeda’s Orexin Franchise

Takeda is the leader in orexin science with a franchise of tailored orexin assets in preclinical and clinical stages with optimized profiles for various orexin disorders. Orexin is a key regulator of sleep and wake patterns and contributes to other essential functions including attention, mood, metabolism and respiration. Oveporexton (TAK-861) is the lead investigational orexin receptor 2 (OX2R) agonist asset in Takeda’s orexin franchise and received Breakthrough Therapy designation for the treatment of excessive daytime sleepiness in narcolepsy type 1 (NT1) from the U.S. Food and Drug Administration and the Center for Drug Evaluation of China’s National Medical Products Administration. The company is also investigating other orexin agonists in populations with orexin levels in the normal range, including TAK-360, an oral OX2R agonist initially being investigated for the treatment of narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) in Phase 2 studies, and other potential indications where orexin signaling is implicated. Additional preclinical assets are also in development including TAK-495, which is expected to enter the clinic in fiscal year 2025.

About Takeda

Takeda is focused on creating better health for people and a brighter future for the world. We aim to discover and deliver life-transforming treatments in our core therapeutic and business areas, including gastrointestinal and inflammation, rare diseases, plasma-derived therapies, oncology, neuroscience and vaccines. Together with our partners, we aim to improve the patient experience and advance a new frontier of treatment options through our dynamic and diverse pipeline. As a leading values-based, R&D-driven biopharmaceutical company headquartered in Japan, we are guided by our commitment to patients, our people and the planet. Our employees in approximately 80 countries and regions are driven by our purpose and are grounded in the values that have defined us for more than two centuries. For more information, visit www.takeda.com.

Media Contacts:

Japanese Media

Yuko Yoneyama

yuko.yoneyama@takeda.com

U.S. and International Media

Rachel Wallace

rachel.wallace2@takeda.com

Important Notice

For the purposes of this notice, “press release” means this document, any oral presentation, any question-and-answer session and any written or oral material discussed or distributed by Takeda Pharmaceutical Company Limited (“Takeda”) regarding this release. This press release (including any oral briefing and any question-and-answer in connection with it) is not intended to, and does not constitute, represent or form part of any offer, invitation or solicitation of any offer to purchase, otherwise acquire, subscribe for, exchange, sell or otherwise dispose of, any securities or the solicitation of any vote or approval in any jurisdiction. No shares or other securities are being offered to the public by means of this press release. No offering of securities shall be made in the United States except pursuant to registration under the U.S. Securities Act of 1933, as amended, or an exemption therefrom. This press release is being given (together with any further information which may be provided to the recipient) on the condition that it is for use by the recipient for information purposes only (and not for the evaluation of any investment, acquisition, disposal or any other transaction). Any failure to comply with these restrictions may constitute a violation of applicable securities laws.

The companies in which Takeda directly and indirectly owns investments are separate entities. In this press release, “Takeda” is sometimes used for convenience where references are made to Takeda and its subsidiaries in general. Likewise, the words “we”, “us” and “our” are also used to refer to subsidiaries in general or to those who work for them. These expressions are also used where no useful purpose is served by identifying the particular company or companies.

Forward-Looking Statements

This press release and any materials distributed in connection with this press release may contain forward-looking statements, beliefs or opinions regarding Takeda’s future business, future position and results of operations, including estimates, forecasts, targets and plans for Takeda. Without limitation, forward-looking statements often include words such as “targets”, “plans”, “believes”, “hopes”, “continues”, “expects”, “aims”, “intends”, “ensures”, “will”, “may”, “should”, “would”, “could”, “anticipates”, “estimates”, “projects”, “forecasts”, “outlook” or similar expressions or the negative thereof. These forward-looking statements are based on assumptions about many important factors,

including the following, which could cause actual results to differ materially from those expressed or implied by the forward-looking statements: the economic circumstances surrounding Takeda’s global business, including general economic conditions in Japan and the United States and with respect to international trade relations; competitive pressures and developments; changes to applicable laws and regulations, including tax, tariff and other trade-related rules; challenges inherent in new product development, including uncertainty of clinical success and decisions of regulatory authorities and the timing thereof; uncertainty of commercial success for new and existing products; manufacturing difficulties or delays; fluctuations in interest and currency exchange rates; claims or concerns regarding the safety or efficacy of marketed products or product candidates; the impact of health crises, like the novel coronavirus pandemic; the success of our environmental sustainability efforts, in enabling us to reduce our greenhouse gas emissions or meet our other environmental goals; the extent to which our efforts to increase efficiency, productivity or cost-savings, such as the integration of digital technologies, including artificial intelligence, in our business or other initiatives to restructure our operations will lead to the expected benefits; and other factors identified in Takeda’s most recent Annual Report on Form 20-F and Takeda’s other reports filed with the U.S. Securities and Exchange Commission, available on Takeda’s website at: https://www.takeda.com/investors/sec-filings-and-security-reports/ or at www.sec.gov. Takeda does not undertake to update any of the forward-looking statements contained in this press release or any other forward-looking statements it may make, except as required by law or stock exchange rule. Past performance is not an indicator of future results and the results or statements of Takeda in this press release may not be indicative of, and are not an estimate, forecast, guarantee or projection of Takeda’s future results.

Medical Information

This press release contains information about products that may not be available in all countries, or may be available under different trademarks, for different indications, in different dosages, or in different strengths. Nothing contained herein should be considered a solicitation, promotion or advertisement for any prescription drugs including the ones under development.

References

1.The topline results of these studies were disclosed on July 14, 2025 in, “Takeda Announces Positive Results from Two Pivotal Phase 3 Studies of Oveporexton (TAK-861) in Narcolepsy Type 1”.

2.Mignot E, Arnulf I, Plazzi G, et al. Efficacy and safety of Oveporexton (TAK-861), an oral orexin receptor 2 agonist for the treatment of narcolepsy type 1: results from a phase 3 randomized study in Europe, Japan, and North America. Presented at: World Sleep Congress 2025; 2025 Sep 8; Singapore.

3.Dauvilliers Y, Antczak J, Buntinx E, et al. Efficacy and safety of Oveporexton (TAK-861) for the treatment of narcolepsy type 1: results from a phase 3 randomized study in Asia, Australia, and Europe. Presented at: World Sleep Congress 2025; 2025 Sep 8; Singapore.

4.Sivam S, Hsiao S, Du Y, et al. Effect of the Oral Orexin Receptor 2 Agonist Oveporexton (TAK-861) on Quality of Life in Individuals with NT1 over 21 weeks. Presented at: World Sleep Congress 2025; 2025 Sep 8; Singapore.

5.Barateau L, Arnulf I, Dauvilliers, Y, et al. Effect of Oral Orexin Receptor 2 Agonist Oveporexton (TAK-861) on the Severity of Symptoms in Individuals With Narcolepsy Type 1: Results From Two Phase 3 Studies. Presented at: World Sleep Congress 2025; 2025 Sep 8; Singapore.

FAQ

What were the primary outcomes of Takeda's Phase 3 trials for oveporexton (TAK)?

Both FirstLight and RadiantLight met all primary and secondary endpoints at week 12, showing statistically significant improvement in wakefulness and other NT1 symptoms with p<0.001 across doses.

How many patients and countries were included in the Phase 3 program for TAK-861?

The program enrolled 273 patients across 19 countries, and more than 95% of participants who completed the studies entered the ongoing long-term extension.

What clinical benefits did oveporexton demonstrate in narcolepsy type 1?

Improvements were shown in MWT wakefulness, ESS sleepiness scores, weekly cataplexy rate (median percent change >80%), symptom severity (NSS-CT), and quality-of-life measures (SF-36, EQ-5D-5L).

Were there any serious safety concerns reported for oveporexton?

No treatment-related serious adverse events were observed; most common adverse events were insomnia and urinary urgency/frequency and were mostly mild to moderate.

Does Takeda expect these Phase 3 results to change its financial guidance for fiscal 2026?

No: Takeda stated the Phase 3 results have no significant impact on the full year consolidated forecast for the fiscal year ending March 31, 2026.