REMEGEN - VOLUNTARY ANNOUNCEMENT - NMPA APPROVES MARKETING FOR THE NEW INDICATION OF TELITACICEPT FOR INJECTION (RC18) FOR THE TREATMENT OF SJOGREN'S SYNDROME(SJOGREN'S DISEASE)

RemeGen Co., Ltd.*

榮昌生物製藥 ( 煙台 ) 股份有限公司

(A joint stock company incorporated in the People's Republic of China with limited liability)

(Stock Code: 9995)

VOLUNTARY ANNOUNCEMENT

NMPA APPROVES MARKETING FOR THE NEW INDICATION OF TELITACICEPT FOR INJECTION (RC18) FOR THE TREATMENT OF

SJÖGREN'S SYNDROME（SJÖGREN'S DISEASE）

This announcement is made by RemeGen Co., Ltd. 榮昌生物製藥(煙台)股份有限公司(the "Company") on a voluntary basis.

The board of directors of the Company (the "Board") is pleased to announce that the Company has received the Drug Registration Certificate approved and issued by the National Medical Products Administration (the "NMPA"). The new indication of Telitacicept for Injection (code: RC18, brand name:泰愛®, approval number: National Medicine Approval S20210008, certificate number: 2026S01909) for the treatment of Sjögren's syndrome (Sjögren's disease) has been approved for marketing.

Pursuant to the Drug Administration Law of the People's Republic of China and relevant regulations, upon review, Telitacicept for Injection complies with the relevant requirements for drug registration. The marketing of this product for the new indication of active Sjögren' s syndrome (Sjögren's disease) (ESSDAI ≥ 5) on the basis of conventional therapy in adult patients is approved.

Telitacicept is a BLyS/APRIL dual-targeting innovative drug independently developed by the Company, and it is the world's first such molecule. BLyS (B-lymphocyte stimulator) and APRIL (a proliferation-inducing ligand) are key cytokines that promote B cell survival, differentiation, and maturation. In patients with Sjögren's disease, serum levels of BLyS and APRIL are significantly elevated, leading to B cell abnormalities and immune system disorders. By simultaneously inhibiting the binding of BLyS and APRIL to B cell surface receptors, the Telitacicept blocks abnormal B cell differentiation and maturation, thereby exerting therapeutic effects.

Sjögren's syndrome is a chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands, resulting in progressive loss of glandular secretion. In severe cases, it may involve extra-glandular organs and cause systemic damage. In 2023, a consensus conference on the nomenclature of Sjögren's syndrome was held in Rome, where it was agreed to rename Sjögren's syndrome (SS) as Sjögren's disease (SjD). SjD is a global disease with a prevalence of 0.3% to 0.7% in the Chinese population, affecting approximately 4.2 million to 9.8 million patients. The approval of this new indication is based on a nationwide multi-center, randomized, double-blind, placebo-controlled Phase III confirmatory clinical study, which is the first global dual-target biologic project for SjD that has successfully completed a Phase III trial and achieved strong positive results. The study demonstrated statistically significant reductions in ESSDAI score at week 24 in both the Telitacicept 160 mg and 80 mg groups compared with placebo, with efficacy persisting through week 48.

The approval of this new indication has further enhanced the market competitiveness of Telitacicept. Due to the characteristics of the pharmaceutical industry, the commercialization of the drugs after marketing approval is subject to various factors including policy environment, market demand and competitive landscape, which entail certain uncertainties. The Company will fulfill its information disclosure obligations in a timely manner in accordance with subsequent developments. Shareholders of the Company and potential investors are advised to exercise caution when dealing in the shares of the Company.

By order of the Board

RemeGen Co., Ltd.* Mr. Wang Weidong

Chairman and executive Director

Yantai, The People's Republic of China

June 8, 2026