EXCEED-ET Study Results Demonstrate Significant Efficacy, with Consistent Treatment Response Across the Overall Essential Thrombocythemia Population

Results Extend Previously Reported Positive Phase 3 SURPASS-ET Study Data, Demonstrating Superior Efficacy Compared with Anagrelide in Hydroxyurea-Resistant or Intolerant Essential Thrombocythemia with Leukocytosis

FDA Review Ongoing of Biologics License Application (sBLA) to Support Ropeginterferon alfa-2b (BESREMi®) Label Expansion

BURLINGTON, Mass, Jan. 12, 2026 — PharmaEssentia USA Corporation, a subsidiary of PharmaEssentia Corporation (TWSE: 6446), a global biopharmaceutical innovator based in Taiwan leveraging deep expertise and proven scientific principles to deliver new biologics in hematology and oncology, today announced positive topline results from its Phase 2b EXCEED-ET clinical trial of ropeginterferon alfa-2b-njft in patients with essential thrombocythemia (ET).

The EXCEED-ET study (NCT05482971) is a North America–based, single-arm, Phase 2b clinical trial that serves as supportive and confirmatory evidence further substantiating the scientific rationale for ropeginterferon alfa-2b-njft’s efficacy in ET. The trial enrolled 91 patients with ET, including 24 patients previously treated with hydroxyurea (HU) and 67 treatment-naïve patients, providing a broad and representative dataset across key ET patient subgroups. The trial results demonstrated a consistent efficacy and treatment response across the overall ET population, with stronger results observed in treatment-naïve patients.

Based on the overall ET population group (intent-to-treat), the response rate at months 10 and 13 was approximately 60.2%. A modified European LeukemiaNet (ELN) response was defined as meeting all three of the following criteria, with individual response rates as follows:

• Reduction in peripheral blood counts (Platelets ≤400 × 10⁹/L and WBC <9.5 × 10⁹/L): 63.7%
• Improvement or no worsening of disease-related signs (splenomegaly): 94.5%
• No bleeding or thrombotic events were observed during the period from Month 10 to Month 13: 100%

Among secondary efficacy endpoints, allele burden analysis also showed encouraging results. The mean JAK2V617F allele burden decreased from 22.2% at baseline to 15.4% at Month 13. Ropeginterferon alfa-2b-njft also demonstrated a consistent safety and tolerability profile.

In treatment-naïve patients, the response rate at months 10 and 13 was 68.0%, compared with 33.4% in patients previously treated with HU, based on preliminary top-line analyses from the EXCEED-ET study.

• Overall response
  • HU-experienced: 33.4%
  • Treatment-naïve: 68.0%
• Reduction in peripheral blood counts
  • HU-experienced: 44.0%
  • Treatment-naïve: 70.7%
• Improvement or no worsening of disease-related signs
  • HU-experienced: 79.9%
  • Treatment-naïve: 100.0%
• No bleeding or thrombotic events were observed during the period from Month 10 to Month 13
  • HU-experienced: 100%
  • Treatment-naïve: 100%

The EXCEED-ET results build on previously reported positive data from the Phase 3 SURPASS-ET study, which demonstrated the clinical benefit of ropeginterferon alfa-2b-njft in patients with ET who were resistant or intolerant to HU. The SURPASS-ET results were published in The Lancet Haematology in November 2025.

“The EXCEED-ET study results further strengthen the growing body of clinical evidence supporting the potential role of ropeginterferon alfa-2b-njft in the treatment of ET,” said Ko-Chung Lin, Ph.D., Founder and CEO of PharmaEssentia. “Together, the EXCEED-ET and SURPASS-ET studies provide complementary data across distinct treatment settings and patient populations, reinforcing the overall clinical profile of ropeginterferon alfa-2b-njft in ET and across the broader myeloproliferative neoplasm (MPN) landscape. The FDA’s review of our supplemental Biologics License Application to expand the ropeginterfapproval.2b-njft (BESREMi®) label to include patients with ET is ongoing, and we are prepared to expand commercialization into this important patient population, pending approval.”

About Essential Thrombocythemia (ET)

Essential thrombocythemia is a rare blood disorder and type of myeloproliferative neoplasm (MPN). It is characterized by the bone marrow overproducing platelets. Patients with ET are at an increased risk of blood clots, abnormal bleeding and enlarged spleens. ET is often caused by genetic mutations such as a JAK2 genetic mutation.

About BESREMi® (ropeginterferon alfa-2b-njft)

BESREMi® is the only FDA-approved treatment indicated for adults with polycythemia vera (PV) that targets the source of the disease. BESREMi® is not chemotherapy, it’s an innovative immunotherapy. Ropeginterferon alfa-2b-njft is a preferred first-line cytoreductive therapy option for both low-risk (symptomatic) and high-risk PV in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). National Comprehensive Cancer Network® (NCCN®)–preferred interventions are based on efficacy, safety, and evidence, and when appropriate, affordability.

BESREMi® holds orphan drug designation in the United States for the treatment of polycythemia vera (PV) in adults. It has received regulatory approval in over 40 countries, including from the European Medicines Agency (2019), the U.S. Food and Drug Administration (2021), and the Pharmaceuticals and Medical Devices Agency in Japan (2023). The product was developed by PharmaEssentia and is manufactured at the company’s facility in Taichung. PharmaEssentia retains full global intellectual property rights across all indications.

Indication

BESREMi® is indicated for the treatment of adults with polycythemia vera.

Important Safety Information

Boxed WARNING: RISK OF SERIOUS DISORDERS

Interferon alfa products may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Patients should be monitored closely with periodic clinical and laboratory evaluations. Therapy should be withdrawn in patients with persistently severe or worsening signs or symptoms of these conditions. In many, but not all cases, these disorders resolve after stopping therapy.

Contraindications

Existence of or history of severe depression, suicidal ideation, or suicide attempt

Hypersensitivity to interferons or any inactive ingredients

Moderate or severe hepatic impairment

History or presence of active serious or untreated autoimmune disease

History of transplantation and receiving immunosuppressant agents

Warnings and Precautions

• Depression and Suicide: Closely monitor patients for any symptoms of psychiatric disorders and, if needed, consider psychiatric consultation and treatment or dosage modifications as listed in the full prescribing information.
• Endocrine Toxicity: Do not use BESREMi® in patients with active serious or untreated endocrine disorders associated with autoimmune disease. Evaluate thyroid function in patients who develop symptoms suggestive of thyroid disease during BESREMi® therapy. Discontinue BESREMi® in patients who develop endocrine disorders that cannot be adequately managed during treatment with BESREMi®.
• Cardiovascular Toxicity: Patients with a history of cardiovascular disorders should be closely monitored for cardiovascular toxicity during BESREMi® therapy. Avoid use of BESREMi® in patients with severe or unstable cardiovascular disease or recent stroke or myocardial infarction.
• Decreased Peripheral Blood Counts: Monitor complete blood counts at baseline, during titration, and every 3-6 months during the maintenance phase.
• Pancreatitis/Colitis/Pulmonary Toxicity: Interrupt BESREMi® treatment in patients with possible pancreatitis, colitis, or pulmonary toxicity and evaluate promptly. Consider discontinuation of BESREMi® in patients with confirmed pancreatitis or who show signs or symptoms of serious ulcerative or hemorrhagic colitis, or who develop pulmonary infiltrates or pulmonary function impairment.
• Ophthalmologic Toxicity: Advise patients to have eye examinations before and during treatment. Discontinue BESREMi® in patients who develop new or worsening eye disorders.
• Hyperlipidemia/Hepatotoxicity/Renal Toxicity: Monitor serum triglycerides, liver enzymes, hepatic function, and serum creatinine at baseline and during therapy. Avoid use of BESREMi® in patients with eGFR <30 mL/min. Discontinue BESREMi® in patients with persistently marked elevated triglycerides, evidence of hepatic decompensation, or if renal impairment develops during treatment.
• Dental and Periodontal Toxicity: Patients should have good oral hygiene and regular dental examinations.
• Dermatologic Toxicity: Consider discontinuation of BESREMi® if clinically significant dermatologic toxicity occurs.
• Driving and Operating Machinery: BESREMi® may impact the ability to drive and use machinery. Patients should not drive or use heavy machinery until they know how BESREMi® affects their abilities. Patients who experience dizziness, somnolence, or hallucination during BESREMi® therapy should avoid driving or using machinery.
• Embryo-Fetal Toxicity: Based on the mechanism of action, BESREMi® can cause fetal harm when administered to a pregnant woman. Obtain a pregnancy test in females of reproductive potential prior to initiating treatment with BESREMi®. Advise females of reproductive potential to use an effective method of contraception during treatment with BESREMi® and for at least 8 weeks after the final dose. Advise women not to breastfeed during treatment and for 8 weeks after the final dose.

Adverse Reactions

The most common adverse reactions reported in >40% of patients were influenza-like illness, arthralgia, fatigue, pruritus, nasopharyngitis, and musculoskeletal pain.

Drug Interactions

Patients on BESREMi® who are receiving concomitant drugs which are CYP450 substrates with a narrow therapeutic index should be monitored to inform the need for dosage modification. Avoid use with myelosuppressive agents, narcotics, hypnotics, or sedatives, and monitor patients receiving the combination for effects of excessive CNS toxicity.

Please see full Prescribing Information, including Boxed Warning.

About PharmaEssentia

PharmaEssentia USA Corporation, located in Burlington, Massachusetts, is a subsidiary of PharmaEssentia Corporation (TWSE: 6446). PharmaEssentia Corporation, headquartered in Taipei, Taiwan, is a global and rapidly growing biopharmaceutical innovator. Leveraging deep expertise and proven scientific principles, PharmaEssentia aims to deliver effective new biologics for challenging diseases in the areas of hematology, oncology, and immunology with one approved product and a diversifying pipeline. Founded in 2003 by a team of Taiwanese-American executives and renowned scientists from U.S. biotechnology and pharmaceutical companies, today PharmaEssentia is expanding its global presence with operations in the U.S., Japan, China, and Korea, along with a world-class biologics production facility in Taichung, Taiwan.

For more information about PharmaEssentia USA, visit the website, LinkedIn or X (formerly Twitter).

Contacts

Media Contact

Muriel Huang

Director, Investor Relations and Corporate Communication

muriel_huang@pharmaessentia.com