SHANGHAI, China, November 11, 2026 — ImmuneOnco Biopharmaceuticals (Shanghai) Inc. (“ImmuneOnco” or the “Company”, HKEX: 01541) today announced the poster presentation of the latest results from the Phase Ib/II study of amulirafusp alfa (IMM0306/IMC-002), the Company’s internally developed CD47×CD20 bispecific fusion protein, in patients with moderate-to-severe active systemic lupus erythematosus (SLE), at the 2026 American College of Rheumatology (ACR) Annual Meeting (ACR 2026). Data are as of September 7, 2026.

Molecular design: dual-targeting synergy

Amulirafusp alfa (IMM0306/IMC-002) is a novel myeloid cell engager (MCE) built on ImmuneOnco’s mAb-Trap platform. It simultaneously targets CD47 and CD20 and is now in clinical development for SLE. In August 2026, the U.S. Food and Drug Administration (FDA) cleared the Company’s investigational new drug (IND) application for IMM0306 in SLE — a key step in the global clinical development of the molecule in autoimmune disease.

Study design: multicenter, open-label, dose escalation

The study was led by Peking University People’s Hospital and enrolled patients with moderate-to-severe active SLE who met the 2019 EULAR/ACR classification criteria, had a SLEDAI-2K score of ≥6 and a BILAG-2004 score of ≥1A or ≥2B. The present analysis of the Phase Ib data included 33 patients across the 0.8, 1.2 and 1.6 mg/kg cohorts.

At baseline, 84.8% of patients were female, and median age was 34 years (range 19–63). Mean SLEDAI-2K was 12.1 (range 6–22); 21.2% of patients had at least one BILAG-2004 grade A domain and 78.8% had a score of at least 2B. Renal involvement was present in 57.6% of patients, with mucocutaneous and musculoskeletal involvement each present in 63.6%, and 33.3% had proteinuria >0.5 g/24 h. All patients were receiving glucocorticoids at baseline, 84.8% antimalarials and 75.8% immunosuppressants; 15.2% had previously received biologic therapy.

Efficacy: high response rates with durability

IMM0306 demonstrated encouraging efficacy in patients with SLE. At Week 24, SRI-4 response rates were 71.4%, 72.7% and 90.9% in the 0.8, 1.2 and 1.6 mg/kg cohorts, respectively; at Week 52, response rates were 66.7%, 75.0% and 100%, respectively, suggesting durability. The 100% at Week 52 corresponds to 3 of 3 patients in the 1.6 mg/kg cohort who had reached the Week 52 assessment.

In addition, most patients with arthritis, rash, alopecia or vasculitis at baseline showed improvement in clinical symptoms, and anti-dsDNA antibodies and complement C3/C4 levels showed trends toward improvement over time.

Safety: generally well tolerated, with no dose-limiting toxicities or cytokine release syndrome

No dose-limiting toxicities (DLTs) were observed at any dose level, and IMM0306 showed a favorable safety profile across the 0.8–1.6 mg/kg cohorts. Most treatment-related adverse events (TRAEs) were grade 1–2. The most common grade ≥3 TRAE was decreased platelet count (3/33, 9.1%), and all cases resolved. One patient (3.0%) discontinued treatment because of a TRAE. No cytokine release syndrome (CRS) and no serious infections were observed.

Pharmacodynamics: deep depletion, reversible reconstitution and stable immunoglobulin levels

Pharmacodynamic analyses showed that peripheral CD19+ B cells were depleted to<5 cells/µL in all patients after the first four doses. From approximately 8 weeks after the first dose, naïve B cells began to reconstitute, while plasmablasts remained suppressed and IgG levels remained stable.

Based on these encouraging data, a randomized, double-blind, placebo-controlled Phase II study is ongoing to further evaluate the efficacy and safety of IMM0306.

Dr. Wenzhi Tian, Chairman, Chief Executive Officer and Chief Scientific Officer of ImmuneOnco, said:

“Amulirafusp alfa (IMM0306) is the first macrophage-based MCE molecule designed and developed by our company. Because macrophages are concentrated in tissues and organs, activating them is expected to clear pathogenic B lymphocytes within affected tissues and thereby deliver durable efficacy. The data presented at ACR 2026 provide early clinical validation of this design concept in SLE — deep depletion, reversible reconstitution and durable responses can be achieved together. We will continue to advance the clinical development of this program.”

Dr. Zhuli Wu, Chief Medical Officer of ImmuneOnco, commented:

“IMM0306 is an innovative bispecific fusion protein targeting CD47 and CD20 that acts on pathogenic B cells with precision through a dual mechanism of action, achieving effective inhibition and clearance of diseased cells. Data presented at the 2026 EULAR Congress had already shown encouraging efficacy and a favorable safety profile; the Phase Ib/II data presented at ACR 2026 further demonstrate the therapeutic potential of IMM0306 in patients with active SLE — SRI-4 response rates at Week 24 reached 90.9%, the trend was maintained through 52 weeks of follow-up, clinical symptoms continued to improve, the overall safety profile was favorable, and grade ≥3 treatment-related adverse events were infrequent. A randomized, double-blind Phase II study is ongoing, and the subcutaneous formulation has begun enrollment. IMM0306 has the potential to become a differentiated treatment option that combines efficacy, safety and greater dosing convenience.”

Note on the data

All clinical data described in this press release are derived from the ACR 2026 poster, with a data cut-off date of September 7, 2026. The Phase Ib study was open-label and dose-escalating and included a limited number of patients; the number of evaluable patients varies by visit. These results may not be predictive of outcomes in larger or randomized studies.

Forward-Looking Statements

This press release contains forward-looking statements that reflect the Company’s current expectations and views of future events. These statements are based on assumptions and are subject to known and unknown risks, uncertainties and other factors that could cause actual results to differ materially. Forward-looking statements include, without limitation, statements regarding the clinical development, regulatory pathway and commercial potential of amulirafusp alfa (IMM0306/IMC-002); the design, timing and outcome of ongoing and planned clinical trials; and the Company’s ability to obtain regulatory approvals. Such statements are not guarantees of future performance and speak only as of the date of this press release. The Company undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law.

Cautionary Statement under Rule 18A.05 of the Rules Governing the Listing of Securities on The Stock Exchange of Hong Kong Limited

The Company cannot assure that amulirafusp alfa (IMM0306/IMC-002) will successfully complete clinical development, obtain regulatory approval or ultimately be commercialized. The Company’s prospects depend on numerous factors beyond its control. Shareholders and potential investors are advised to exercise caution when dealing in the securities of the Company.