Shanghai, China, January 19, 2026 – ImmuneOnco Biopharmaceuticals (Shanghai) Inc. ("ImmuneOnco", HKEX stock code: 01541.HK) announced that its subsidiary, ImmuneCare Biopharmaceuticals (Shanghai) Co., Ltd. ("ImmuneCare"), has successfully completed enrollment of all subjects in the first cohort of the Multiple Ascending Dose (MAD) study for IMC-003/IMM72 (ActRIIA-Fc fusion protein) in pulmonary arterial hypertension (PAH). This marks another significant milestone achieved rapidly following the successful completion of the Single Ascending Dose (SAD) stage in early January 2026, signifying a comprehensive acceleration of the clinical development progress for IMC-003.

The successful completion of enrollment for the first MAD cohort fully demonstrates the professional execution capabilities and efficient collaborative standards of ImmuneCare's clinical research team. The enrolled subjects are postmenopausal women with low bone mineral density. The study will further evaluate the safety, tolerability, pharmacokinetics/pharmacodynamics (PK/PD) characteristics, and preliminary efficacy of IMC-003 under multiple-dose conditions. This will accumulate critical data for subsequent Phase II clinical studies in PAH patients and provide key support for expanding the clinical trial protocol design for osteoporosis indications.

Pulmonary arterial hypertension (PAH) is a malignant, progressive pulmonary vascular disease characterized by persistently elevated pulmonary arterial pressure and pulmonary vascular resistance (PVR). Patients typically experience early symptoms including dyspnea, decreased exercise capacity, chest tightness, and fatigue. Without timely treatment, the disease progressively deteriorates, ultimately leading to right heart failure and death. Untreated PAH patients have an extremely low 5-year survival rate, earning the disease the moniker "cardiovascular cancer." Merck's novel drug Winrevair™, approved in the United States in March 2024, became the only therapy capable of reversing disease progression in this field. In its first full year post-launch, it achieved over US$1 billion in sales, establishing itself as a blockbuster drug.

IMC-003 is an independently developed activin receptor type IIA (ActRIIA)-Fc fusion protein by ImmuneCare, featuring a mechanism of action similar to Winrevair™ that fundamentally improves the homeostasis of vascular smooth muscle cells and pulmonary vascular remodeling from a pathogenic perspective. Compared to Winrevair™, IMC-003 possesses unique differentiated characteristics. Its extracellular domain of the ActRIIA receptor has been genetically engineered to enhance binding and blocking activity against the ligand Activin A while improving drug quality homogeneity. In Sugen5416-hypoxia and monocrotaline (MCT)-induced pulmonary arterial hypertension animal models, IMC-003 demonstrated superior efficacy compared to Winrevair™. The high selectivity of IMC-003 for Activin A enables the potential for achieving favorable therapeutic effects at lower clinical doses, possibly reducing bleeding risk and demonstrating a better safety profile.

Dr. Wenzhi Tian, Founder, Chairman, CEO and CSO of ImmuneOnco, and Founder of ImmuneCare, stated:

"The successful completion of enrollment for the first MAD cohort of IMC-003 represents another critical milestone in ImmuneCare's R&D progress in the field of pulmonary arterial hypertension, a serious disease area. Our goal is to provide PAH patients worldwide with safer and more effective treatment options through innovative molecular design. We currently hold a leading position domestically in drug development targeting this pathway. We anticipate obtaining complete Phase I data within 2026 and advancing this differentiated innovative therapy to Phase II clinical trials and commercialization at the earliest opportunity."