Positive Phase 3 Results Support ZIIHERA® as HER2-Targeted Therapy-of-Choice and Combination with TEVIMBRA® and Chemotherapy as New Standard of Care in First-Line HER2-Positive Locally Advanced or Metastatic Gastroesophageal Adenocarcinoma

ZIIHERA plus TEVIMBRA and chemotherapy demonstrated clinically meaningful and statistically significant improvements in PFS and OS versus trastuzumab and chemotherapy

ZIIHERA plus chemotherapy showed a clinically meaningful and statistically significant improvement in PFS versus trastuzumab and chemotherapy, and a clinically meaningful effect with a strong trend toward statistical significance for OS at the first interim analysis

First Phase 3 trial in 15 years to demonstrate a clinical benefit in this patient population with a novel HER2-targeted therapy

BeOne Medicines Ltd. (NASDAQ:ONC, HKEX: 06160, SSE: 688235)), a global oncology company, today announced positive top-line results from the Phase 3 HERIZON-GEA-01 trial evaluating ZIIHERA^® (zanidatamab), a HER2-targeted bispecific antibody, in combination with chemotherapy, with or without PD-1 inhibitor TEVIMBRA^® (tislelizumab), as first-line treatment for HER2-positive (HER2+) locally advanced or metastatic gastroesophageal adenocarcinoma (GEA), including cancers of the stomach, gastroesophageal junction, and esophagus.

Both ZIIHERA plus TEVIMBRA and chemotherapy and ZIIHERA plus chemotherapy demonstrated clinically meaningful and highly statistically significant improvements in progression-free survival (PFS) compared to the control arm, trastuzumab plus chemotherapy.

ZIIHERA plus TEVIMBRA and chemotherapy also demonstrated clinically meaningful and statistically significant improvements in overall survival (OS), and ZIIHERA plus chemotherapy demonstrated a clinically meaningful effect with a strong trend toward statistical significance for OS compared to the control arm at the time of this first analysis. The trial is ongoing with an additional planned OS interim analysis for ZIIHERA plus chemotherapy currently expected in mid-2026.

These PFS and OS benefits were observed in the ZIIHERA plus TEVIMBRA and chemotherapy arm versus the control arm in both PD-L1 positive and PD-L1 negative subgroups. Supportive of the primary efficacy endpoints, both combination arms demonstrated improvements in the key secondary endpoints of objective response rate (ORR) and duration of response (DOR) versus the control arm.

"Gastric, gastroesophageal junction, and esophageal adenocarcinoma remain major global health challenges, particularly in advanced stages where outcomes are still poor," said Dr. Sun Young Rha, Professor of Medical Oncology at the Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea, and investigator on the HERIZON-GEA-01 study. "The positive results of this trial demonstrate that zanidatamab-based combination regimens have the potential to reshape clinical practice for the first-line treatment of HER2-positive metastatic gastroesophageal disease."

"These results represent meaningful progress for a patient community in urgent need of new treatment options. With the high incidence of GEA across many regions where we hold rights to ZIIHERA, we have the opportunity to deliver a major advancement for patients in an area of high unmet need," said Mark Lanasa, M.D., Ph.D., Chief Medical Officer, Solid Tumors at BeOne. "This milestone underscores our dedication to advancing therapies for gastrointestinal cancers and demonstrates the potential of TEVIMBRA as an anti-PD-1 backbone in combination regimens. We look forward to collaborating with health authorities in our licensed territories, and to expanding TEVIMBRA's label to include this combination."

The safety profile of ZIIHERA in combination with chemotherapy, with and without TEVIMBRA, was generally consistent with the known safety profile of each agent with no new safety signals observed in the two investigational combination arms and supports the overall benefit-risk profile of ZIIHERA for use in this indication.

These data will be submitted for presentation at a major medical meeting in the first quarter of 2026.

About the HERIZON-GEA-01 Phase 3 Trial

HERIZON-GEA-01 (NCT05152147) is a global, randomized, open-label Phase 3 trial, conducted jointly with Jazz Pharmaceuticals, to evaluate and compare the efficacy and safety of ZIIHERA plus chemotherapy, with or without TEVIMBRA, to the standard of care (trastuzumab plus chemotherapy) as first-line treatment for adult patients with advanced/metastatic HER2+ GEA. The trial randomized 914 patients from approximately 300 trial sites in more than 30 countries. Appropriate patients for this trial had unresectable locally advanced, recurrent or metastatic HER2+ GEA (adenocarcinomas of the stomach or esophagus, including the gastroesophageal junction), defined as 3+ HER2 expression by IHC or 2+ HER2 expression by IHC with ISH positivity per central assessment. Patients were randomized to the three trial arms: ZIIHERA in combination with chemotherapy and TEVIMBRA; ZIIHERA in combination with chemotherapy; and trastuzumab plus chemotherapy. The trial is evaluating dual primary endpoints, PFS per blinded independent central review (BICR) and OS.

About Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinoma (GEA) is the fifth most common cancer worldwide, and approximately 20% of patients have HER2-positive disease^.1,2,3 HER2-positive GEA has high morbidity and mortality, and patients are urgently in need of new treatment options. The overall prognosis for patients with GEA remains poor, with a global five-year survival rate of less than 30% for gastric cancer and about 19% for GEA.⁴

About ZIIHERA^® (zanidatamab)

ZIIHERA (zanidatamab) is a bispecific human epidermal growth factor receptor 2, or HER2-directed antibody that binds to two extracellular sites on HER2. Binding of zanidatamab with HER2 results in internalization leading to a reduction in HER2 expression of the receptor on the tumor cell surface. Zanidatamab induces complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). These mechanisms result in tumor growth inhibition and cell death in vitro and in vivo.⁵

Zanidatamab is being developed in multiple clinical trials as a targeted treatment option for patients with solid tumors that express HER2. Zanidatamab is approved in China for treating HER2-high-expression biliary tract cancer (BTC). ZIIHERA also has been approved in both the U.S. and the European Union for eligible BTC patients. Zanidatamab is being developed by Jazz and BeOne under license agreements from Zymeworks, which first developed the molecule. BeOne has licensed zanidatamab from Zymeworks in Asia (excluding India and Japan), Australia and New Zealand. Jazz Pharmaceuticals has rights in all other countries.

ZIIHERA is a registered trademark of Zymeworks BC Inc.

About TEVIMBRA (tislelizumab)

TEVIMBRA is a uniquely designed humanized immunoglobulin G4 (IgG4) anti-programmed cell death protein 1 (PD-1) monoclonal antibody with high affinity and binding specificity against PD-1. It is designed to minimize binding to Fc-gamma (Fcγ) receptors on macrophages, helping to aid the body's immune cells to detect and fight tumors.

TEVIMBRA is the foundational asset of BeOne's solid tumor portfolio and has shown potential across multiple tumor types and disease settings. The global TEVIMBRA clinical development program includes almost 14,000 patients enrolled to date in 35 countries and regions across 70 trials, including 22 registration-enabling studies. TEVIMBRA is approved in at least one indication in 47 markets, and more than 1.8 million patients have been treated globally.

U.S. Indication and Important Safety Information for TEVIMBRA (tislelizumab-jsgr) injection

IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS

Severe and Fatal Immune-Mediated Adverse Reactions

TEVIMBRA is a monoclonal antibody that belongs to a class of drugs that bind to either the programmed death receptor-1 (PD-1) or PD-ligand 1 (PD-L1), blocking the PD-1/PD-L1 pathway, thereby removing inhibition of the immune response, potentially breaking peripheral tolerance and inducing immune-mediated adverse reactions.

Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue. Immune-mediated adverse reactions can occur at any time after starting treatment with a PD-1/PD-L1 blocking antibody. While immune-mediated adverse reactions usually manifest during treatment with PD-1/PD-L1 blocking antibodies, immune-mediated adverse reactions can also manifest after discontinuation of PD-1/PD-L1 blocking antibodies. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated reactions.

Early identification and management of immune-mediated adverse reactions are essential to ensure safe use of PD-1/PD-L1 blocking antibodies. Monitor patients closely for symptoms and signs that may be clinical manifestations of underlying immune-mediated adverse reactions. Evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. In cases of suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate.

Withhold or permanently discontinue TEVIMBRA depending on severity. In general, if TEVIMBRA requires interruption or discontinuation, administer systemic corticosteroid therapy (1 to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose immune-mediated adverse reactions are not controlled with corticosteroids.

Immune-Mediated Pneumonitis

TEVIMBRA can cause immune-mediated pneumonitis, which can be fatal. In patients treated with other PD-1/PD-L1 blocking antibodies, the incidence of pneumonitis is higher in patients who have received prior thoracic radiation.

Immune-mediated pneumonitis occurred in 4.9% (96/1972) of patients receiving TEVIMBRA, including fatal (0.1%), Grade 4 (0.3%), Grade 3 (1.6%) and Grade 2 (1.9%) adverse reactions. Pneumonitis led to permanent discontinuation of TEVIMBRA in 38 (1.9%) patients and withholding of TEVIMBRA in 32 (1.6%) patients.

Seventy-four (77.1%) of the 96 patients received systemic corticosteroids. Sixty-five (67.7%) of the 96 patients received high-dose systemic corticosteroids. Immune-mediated pneumonitis resolved in 50% of the 96 patients. Of the 32 patients in whom TEVIMBRA was withheld for pneumonitis, 20 (62.5%) reinitiated TEVIMBRA after symptom improvement; of these, 2 (10%) patients had recurrence of pneumonitis.

Immune-Mediated Colitis

TEVIMBRA can cause immune-mediated colitis, which can be fatal. Cytomegalovirus (CMV) infection/reactivation has been reported in patients with corticosteroid-refractory immune-mediated colitis treated with PD-1/PD-L1 blocking antibodies. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude alternative etiologies.

Immune-mediated colitis occurred in 0.8% (16/1972) of patients receiving TEVIMBRA, including Grade 3 (0.3%) and Grade 2 (0.4%) adverse reactions. Colitis led to permanent discontinuation of TEVIMBRA in 4 (0.2%) patients and withholding of TEVIMBRA in 5 (0.3%) patients. Twelve (75%) of the 16 patients received systemic corticosteroids. Eight (50%) of the 16 patients received high-dose systemic corticosteroids. Two (12.5%) of the 16 patients received immunosuppressive treatment. Immune-mediated colitis resolved in 93.8% of the 16 patients. All 5 patients in whom TEVIMBRA was withheld for colitis reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of colitis.

Immune-Mediated Hepatitis

TEVIMBRA can cause immune-mediated hepatitis, which can be fatal.

Immune-mediated hepatitis occurred in 1.2% (24/1972) of patients receiving TEVIMBRA, including fatal (0.1%), Grade 4 (0.2%), Grade 3 (0.5%) and Grade 2 (0.4%) adverse reactions. Immune-mediated hepatitis led to permanent discontinuation in 3 (0.2%) patients and withholding of TEVIMBRA in 13 (0.7%) patients. Eighteen (75%) of the 24 patients received systemic corticosteroids. Thirteen (54.2%) of the 24 patients received high-dose systemic corticosteroids. Two patients (8.3%) of the 24 patients received immunosuppressive treatment. Immune-mediated hepatitis resolved in 70.8% of the 24 patients. Of the 13 patients in whom TEVIMBRA was withheld for hepatitis, 7 (53.8%) reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of hepatitis.

Immune-Mediated Endocrinopathies

Adrenal Insufficiency

TEVIMBRA can cause immune-mediated adrenal insufficiency. For Grade 2 or higher adrenal insufficiency, initiate symptomatic treatment, including hormone replacement as clinically indicated. Withhold TEVIMBRA depending on severity.

Immune-mediated adrenal insufficiency occurred in 0.4% (8/1972) of patients receiving TEVIMBRA, including Grade 4 (0.1%), Grade 3 (0.1%) and Grade 2 (0.3%) adverse reactions. Adrenal insufficiency did not lead to permanent discontinuation of TEVIMBRA. TEVIMBRA was withheld in 7 (0.4%) patients. All 8 patients received systemic corticosteroids. Three (37.5%) of the 8 patients received high-dose systemic corticosteroids. Adrenal insufficiency resolved in 25% of the 8 patients. Of the 7 patients in whom TEVIMBRA was withheld for adrenal insufficiency, 5 (71.4%) reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of adrenal insufficiency.

Hypophysitis

TEVIMBRA can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms associated with mass effect such as headache, photophobia, or visual field defects. Hypophysitis can cause hypopituitarism. Initiate hormone replacement as clinically indicated. Withhold or permanently discontinue TEVIMBRA depending on severity.

Hypophysitis/hypopituitarism occurred in 0.2% (4/1972) of patients receiving TEVIMBRA, including a Grade 2 (0.2%) adverse reaction. No TEVIMBRA treatment discontinuation was required, while treatment was withheld in 1 (0.1%) patient. Three (75%) of the 4 patients received systemic corticosteroids. One (25%) of the 4 patients received high-dose systemic corticosteroids. Hypophysitis/hypopituitarism did not resolve in the 4 patients. For the 1 patient where TEVIMBRA was withheld for hypophysitis/hypopituitarism, there was no recurrence of hypophysitis/hypopituitarism.

Thyroid Disorders

TEVIMBRA can cause immune-mediated thyroid disorders. Thyroiditis can present with or without endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement for hypothyroidism or institute medical management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue TEVIMBRA depending on severity.

Thyroiditis: Immune-mediated thyroiditis occurred in 1.2% (24/1972) of patients receiving TEVIMBRA, including Grade 2 (0.5%) adverse reactions. Thyroiditis did not lead to permanent discontinuation of TEVIMBRA. TEVIMBRA was withheld in 3 (0.2%) patients. Two (8.3%) of the 24 patients received systemic corticosteroids. Thyroiditis resolved in 41.7% of the 24 patients. All three patients in whom TEVIMBRA was withheld for thyroiditis reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of thyroiditis.

Hyperthyroidism: Immune-mediated hyperthyroidism occurred in 4.8% (95/1972) of patients receiving TEVIMBRA, including Grade 3 (0.1%) and Grade 2 (0.9%) adverse reactions. Hyperthyroidism led to the permanent discontinuation of TEVIMBRA in 1 (0.1%) patient and withholding of TEVIMBRA in 4 (0.2%) patients. One (1.1%) of the 95 patients received systemic corticosteroids. Hyperthyroidism resolved in 75.8% of the 95 patients. Of the 4 patients in whom TEVIMBRA was withheld for hyperthyroidism, 3 (75%) reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of hyperthyroidism.

Hypothyroidism: Immune-mediated hypothyroidism occurred in 12.7% (250/1972) of patients receiving TEVIMBRA, including Grade 4 (0.1%) and Grade 2 (6.8%) adverse reactions. TEVIMBRA was not permanently discontinued in any patient, while treatment was withheld in 7 (0.4%) patients. Two (0.8%) of the 250 patients received systemic corticosteroids and 158 patients (63.2%) received hormone replacement therapy. Hypothyroidism resolved in 31.6% of the 250 patients. The majority (51.6%) of patients with hypothyroidism required long-term thyroid hormone replacement. Of the 7 patients in whom TEVIMBRA was withheld for hypothyroidism, 6 (85.7%) reinitiated TEVIMBRA after symptom improvement; of these, none of the patients had recurrence of hypothyroidism.

Type 1 Diabetes Mellitus, which can present with Diabetic Ketoacidosis

Diabetes mellitus has been reported with PD-1/PD-L1 blocking antibodies. Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with insulin as clinically indicated. Withhold or permanently discontinue TEVIMBRA depending on severity.

Diabetes mellitus occurred in 0.9% (18/1972) of patients receiving TEVIMBRA, including Grade 4 (0.1%), Grade 3 (0.4%) and Grade 2 (0.4%) adverse reactions. TEVIMBRA was permanently discontinued in 3 (0.2%) patients and TEVIMBRA treatment was withheld in 3 (0.2%) patients. Twelve (66.7%) patients received insulin therapy for diabetes mellitus. Diabetes mellitus resolved in 27.8% of the 18 patients. Of the 3 patients in whom TEVIMBRA was withheld for diabetes mellitus, none of the patients reinitiated TEVIMBRA after symptom improvement.

Immune-Mediated Nephritis with Renal Dysfunction

TEVIMBRA can cause immune-mediated nephritis, which can be fatal.

Immune-mediated nephritis with renal dysfunction occurred in 0.3% (5/1972) of patients receiving TEVIMBRA, including Grade 3 (0.1%) and Grade 2 (0.2%) adverse reactions. TEVIMBRA was permanently discontinued in 1 (0.1%) patient and treatment was withheld in 3 (0.2%) patients. Three (60%) of the 5 patients received systemic corticosteroids. All 3 (60%) of the 5 patients received high-dose systemic corticosteroids. Nephritis with renal dysfunction resolved in 40.0% of the 5 patients. Of the 3 patients in whom TEVIMBRA was withheld for nephritis, 2 (66.7%) reinitiated TEVIMBRA after symptom improvement and one (50%) patient had recurrence of nephritis.

Immune-Mediated Dermatologic Adverse Reactions

TEVIMBRA can cause immune-mediated rash or dermatitis. Cases of severe cutaneous adverse reactions (SCARs), including exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), have been reported, some with fatal outcome. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate non-exfoliative rashes. Withhold or permanently discontinue TEVIMBRA depending on severity.

Immune-mediated dermatologic adverse reactions occurred in 15.3% (301/1972) of patients receiving TEVIMBRA, including Grade 4 (0.1%), Grade 3 (0.9%) and Grade 2 (3.5%) adverse reactions. Dermatologic adverse reactions led to permanent discontinuation of TEVIMBRA in 2 (0.1%) patients and withholding of TEVIMBRA in 18 (0.9%) patients. Thirty (10.0%) of the 301 patients received systemic corticosteroids. Thirteen (4.3%) of the 301 patients received high-dose systemic corticosteroids. Immune-mediated skin reactions resolved in 190 (63.1%) of the 301 patients. Of the 18 patients in whom TEVIMBRA was withheld for dermatologic adverse reactions, 15 (83.3%) reinitiated TEVIMBRA after symptom improvement; of these, 1 (6.7%) patient had recurrence of immune-mediated dermatologic adverse reactions.

Other Immune-Mediated Adverse Reactions

The following clinically significant immune-mediated adverse reactions occurred at an incidence of less than 1% each in 1972 patients who received TEVIMBRA: myositis, myocarditis, arthritis, polymyalgia rheumatica, and pericarditis.

The following additional clinically significant immune-mediated adverse reactions have been reported with other PD-1/PD-L1 blocking antibodies, including severe or fatal cases.

Cardiac/Vascular: Vasculitis.

Nervous System: Meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia gravis (including exacerbation), Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy.

Ocular: Uveitis, iritis, and other ocular inflammatory toxicities can occur. Some cases can be associated with retinal detachment. Various grades of visual impairment, including blindness, can occur. If uveitis occurs in combination with other immune-mediated adverse reactions, consider a Vogt-Koyanagi-Harada-like syndrome, as this may require treatment with systemic steroids to reduce the risk of permanent vision loss.

Gastrointestinal: Pancreatitis including increases in serum amylase and lipase levels, gastritis, duodenitis.

Musculoskeletal and Connective Tissue: Polymyositis, rhabdomyolysis and associated sequelae including renal failure.

Endocrine: Hypoparathyroidism.

Other (Hematologic/Immune): Hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis, systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi lymphadenitis), sarcoidosis, immune thrombocytopenic purpura, solid organ transplant rejection, other transplant (including corneal graft) rejection.

Infusion-Related Reactions

TEVIMBRA can cause severe or life-threatening infusion-related reactions. Infusion-related reactions occurred in 5% (99/1972) patients receiving TEVIMBRA, including Grade 3 or higher (0.2%) reactions. Monitor patients for signs and symptoms of infusion-related reactions.

Slow the rate of infusion for mild (Grade 1) and interrupt the infusion for moderate (Grade 2) infusion-related reactions. For severe (Grade 3) or life-threatening (Grade 4) infusion-related reactions, stop infusion and permanently discontinue TEVIMBRA.

Complications of Allogeneic HSCT

Fatal and other serious complications can occur in patients who receive allogeneic hematopoietic stem cell transplantation (HSCT) before or after being treated with a PD-1/PD-L1 blocking antibody. Transplant-related complications include hyperacute graft-versus-host disease (GVHD), acute GVHD, chronic GVHD, hepatic veno-occlusive disease after reduced intensity conditioning, and steroid-requiring febrile syndrome (without an identified infectious cause). These complications may occur despite intervening therapy between PD-1/PD-L1 blockade and allogeneic HSCT.

Follow patients closely for evidence of transplant-related complications and intervene promptly. Consider the benefit versus risks of treatment with a PD-1/PD-L1 blocking antibody prior to or after an allogeneic HSCT.

Embryo-Fetal Toxicity

Based on its mechanism of action, TEVIMBRA can cause fetal harm when administered to a pregnant woman. Animal studies have demonstrated that inhibition of the PD-1/PD-L1 pathway can lead to increased risk of immune-mediated rejection of the developing fetus resulting in fetal death. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with TEVIMBRA and for 4 months after the last dose.

ADVERSE REACTIONS

First-line Treatment of Unresectable Advanced or Metastatic Esophageal Carcinoma (ESCC)

Permanent discontinuation of TEVIMBRA due to adverse reactions occurred in 13% of patients. The adverse reaction which resulted in discontinuation in ≥2% of patients was pneumonitis (2.2%).

Dosage interruptions of TEVIMBRA due to adverse reactions occurred in 52% of patients. Adverse reactions which required dosage interruption in ≥2% of patients were neutrophil count decreased (7%), fatigue (6%), pneumonia (6%), anemia (4.3%), neutropenia (4.3%), white blood cell count decreased (4.3%), rash (3.7%), dysphagia (2.8%), platelet count decreased (2.8%), pyrexia (2.8%), and diarrhea (2.2%).

The most common (≥20%) adverse reactions, including laboratory abnormalities were decreased neutrophil count, decreased sodium, increased glucose, anemia, fatigue, decreased appetite, increased AST, decreased potassium, increased serum creatinine, decreased calcium, increased ALT, diarrhea, stomatitis, and vomiting.

Previously Treated Unresectable Advanced or Metastatic ESCC

Permanent discontinuation of TEVIMBRA due to an adverse reaction occurred in 19% of patients. Adverse reactions which resulted in permanent discontinuation in ≥1% of patients were hemorrhage, pneumonitis (including pneumonitis and immune-mediated pneumonitis), and pneumonia.

Dosage interruptions of TEVIMBRA due to an adverse reaction occurred in 23% of patients. Adverse reactions which required dosage interruptions in ≥2% of patients were pneumonia, pneumonitis, and fatigue.

The most common (≥20%) adverse reactions, including laboratory abnormalities, were increased glucose, decreased hemoglobin, decreased lymphocytes, decreased sodium, decreased albumin, increased alkaline phosphatase, anemia, fatigue, increased AST, musculoskeletal pain, decreased weight, increased ALT, and cough.

Treatment of Previously Untreated Unresectable or Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma (G/GEJ)

Permanent discontinuation of TEVIMBRA due to an adverse drug reaction occurred in 16% of patients. Adverse drug reactions which resulted in permanent discontinuation in ≥1% of patients were death, fatigue, and pneumonitis.

Dosage interruption of TEVIMBRA in the TEVIMBRA plus chemotherapy arm due to an adverse drug reaction occurred in 49% of patients. Adverse drug reactions which required dosage modifications in ≥2% of patients were, platelet count decreased (12%), neutrophil count decreased (10%), neutropenia (6%), white blood cell count decreased (6%), increased AST (4.8%), increased ALT (3.8%), increased blood bilirubin (3%), COVID-19 (3%), thrombocytopenia (2.8%), leukopenia (2.6%), pneumonitis (2.2%), and pneumonia (2%).

The most common (≥20%) adverse reactions, including laboratory abnormalities, for TEVIMBRA in combination with chemotherapy were nausea, fatigue, decreased appetite, anemia, peripheral sensory neuropathy, vomiting, decreased platelet count, decreased neutrophil count, increased aspartate aminotransferase, diarrhea, abdominal pain, increased alanine aminotransferase, decreased white blood cell count, decreased weight, and pyrexia.

INDICATIONS

TEVIMBRA is a programmed death receptor-1 (PD-1)-blocking antibody indicated for:

Esophageal Cancer

• in combination with platinum-containing chemotherapy for the first-line treatment of adults with unresectable or metastatic esophageal squamous cell carcinoma (ESCC) whose tumors express PD-L1 (≥1).
• as a single-agent, for the treatment of adults with unresectable or metastatic ESCC after prior systemic chemotherapy that did not include a PD-(L)1 inhibitor.

Gastric Cancer

• in combination with platinum and fluoropyrimidine-based chemotherapy for the first-line treatment of adults with unresectable or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma whose tumors express PD-L1 (≥1).

Please see full U.S. Prescribing Information including the U.S. Medication Guide.

The information in this press release is intended for a global audience. Product indications vary by region.

About BeOne Medicines

BeOne Medicines is a global oncology company domiciled in Switzerland that is discovering and developing innovative treatments that are more accessible to cancer patients worldwide. With a portfolio spanning hematology and solid tumors, BeOne is expediting development of its diverse pipeline of novel therapeutics through its internal capabilities and collaborations. With a growing global team of nearly 12,000 colleagues spanning six continents, the Company is committed to radically improving access to medicines for far more patients who need them. To learn more about BeOne, please visit www.beonemedicines.com and follow us on LinkedIn, X, Facebook and Instagram.

Forward-Looking Statement

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws, including statements regarding the potential benefits of ZIIHERA and TEVIMBRA; zanidatamab-based regimens' potential to reshape clinical practice; TEVIMBRA's potential as an anti-PD-1 backbone in combination regimens; BeOne's commitment to advancing therapies for gastrointestinal cancers; BeOne's plans to expand TEVIMBRA's label to include this combination; BeOne's expectations regarding ZIIHERA's and TEVIMBRA's clinical development and regulatory milestones; BeOne's plans to present the data at a future medical meeting; and BeOne's plans, commitments, aspirations, and goals under the heading "About BeOne Medicines." Actual results may differ materially from those indicated in the forward-looking statements as a result of various important factors, including BeOne's ability to demonstrate the efficacy and safety of its drug candidates; the clinical results for its drug candidates, which may not support further development or marketing approval; actions of regulatory agencies, which may affect the initiation, timing, and progress of clinical trials and marketing approval; BeOne's ability to achieve commercial success for its marketed medicines and drug candidates, if approved; BeOne's ability to obtain and maintain protection of intellectual property for its medicines and technology; BeOne's reliance on third parties to conduct drug development, manufacturing, commercialization, and other services; BeOne's limited experience in obtaining regulatory approvals and commercializing pharmaceutical products and its ability to obtain additional funding for operations and to complete the development of its drug candidates and achieve and maintain profitability; and those risks more fully discussed in the section entitled "Risk Factors" in BeOne's most recent quarterly report on Form 10-Q, as well as discussions of potential risks, uncertainties, and other important factors in BeOne's subsequent filings with the U.S. Securities and Exchange Commission. All information in this press release is as of the date of this press release, and BeOne undertakes no duty to update such information unless required by law.

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