SHANGHAI, 17 June, 2026— Hansoh Pharmaceutical Group Co., Ltd. (“Hansoh Pharma,” 03692.HK) today announced that encouraging results from the Phase 2 study of Ris-Rez (ARTEMIS-002), in patients with heavily pretreated R/R sarcomas, were presented in the Rapid Oral Session at the ESMO Targeted Anticancer Therapies Asia Congress (2026), held from 12-14 June in Hong Kong SAR, China.

Risvutatug Rezetecan (Ris-Rez, previously known as HS-20093/GSK5764227) is a B7-H3–targeted antibody–drug conjugate (ADC) under clinical development for solid tumors. At ESMO TAT Asia 2026, long-term follow-up results were presented for adult and adolescent (12-<18 years) patients with osteosarcoma, as well as for adult patients with soft tissue sarcoma (STS) from this study. The pharmacokinetic (PK) and translational results were also disclosed.

The study results showed:

● As of September 20, 2025, a total of 68 patients with R/R sarcomas (42 adult osteosarcomas patients in cohort 1; 20 other sarcomas patients in cohort 2; 6 adolescent osteosarcoma patients in cohort 3) were enrolled. At baseline, most patients had extensive metastasis and were heavily treated with a median of 2 - 3 prior therapy lines.

● Anti-tumor activity in osteosarcoma: Among the 45 evaluable osteosarcoma patients from Cohorts 1 and 3, the ORRs at the 8.0 mg/kg and 12.0 mg/kg doses were 6.7% and 20.0%, respectively, with corresponding median PFS of 4.0 months and 8.3 months, respectively. With longer follow-up, the OS data for the 8.0 mg/kg osteosarcoma cohort have been updated, with a median OS of 24.5 months, 12.0 mg/kg osteosarcoma cohort’s median OS not yet reached. The ORRs for adult and adolescent patients at the 12.0 mg/kg dose were 20.8% and 16.7%, respectively, with corresponding median PFS of 8.4 months and 6.1 months, respectively.

● Promising anti-tumor activity observed in patients with soft tissue sarcoma (STS): A total of 13 STS patients were enrolled. With a median follow-up duration of 22.1 months, cORR was 23.1%, DCR was 92.3%, the median PFS was 9.4 months, and median OS was 22.6 months.

●  Manageable safety profile: With longer follow-up, the safety profile of Ris-Rez remained consistent with previous reports. The most common CTCAE Grade (G)≥3 Treatment-Related Adverse Events (TRAEs) were hematological toxicities, which were largely reversible and manageable with standard supportive care.

●  PK characteristics and biomarker analysis: Single-dose PK showed approximately dose-proportional exposure escalation from 8.0 to 12.0 mg/kg, with no meaningful accumulation upon repeat dosing; exposures were comparable between adult and adolescent patients, and no B7-H3 expression-outcome relationship was observed in osteosarcoma.

A confirmatory phase 3 study (NCT06935409/ CTR20251474) is evaluating Ris-Rez 12.0 mg/kg Q3W for the efficacy and safety in R/R osteosarcoma in Chinese patients. 

Details of the rapid oral presentation are as follows:

◆ Poster Title: ARTEMIS-002: A Phase 2 Study of Risvutatug Rezetecan (Ris-Rez) in Patients with Relapsed or Refractory Sarcomas

◆ Session: Rapid Oral presentation

◆ Abstract No.: FPN: 4RO

◆ Date/Time: 11:45 - 13:00, Sun, June 14, 2026 UTC+8

◆ Presenter: Lu Xie; Peking University People’s Hospital, Beijing, China

About Risvutatug Rezetecan

Risvutatug Rezetecan (Ris-Rez, previously known as HS-20093, GSK5764227), a B7-H3-targeted ADC self-developed by Hansoh Pharma, is composed of a fully human anti-B7-H3 monoclonal antibody covalently linked to topoisomerase inhibitor (TOPOi) payload. As of now, Ris-Rez has entered phase 3 clinical research for the treatment of osteosarcoma indication and small cell lung cancer indication in China, and is also undergoing multiple proofs of concept (PoC) clinical studies for the treatment of small cell lung cancer, non-small cell lung cancer, head and neck cancer, prostate cancer, esophageal squamous cell carcinoma, colorectal cancer and other solid tumors.

In December 2023, Hansoh Pharma granted GSK an exclusive worldwide license, excluding Chinese mainland, Hong Kong, Macau and Taiwan, to develop, manufacture and commercialize Ris-Rez, which is currently undergoing Phase 1 and Phase 3 clinical trials overseas by GSK.

In February 2025, the National Medical Products Administration (NMPA) listed Ris-Rez as a Breakthrough-Therapy-Designated (BTD) Drug, with the proposed indication for the treatment of patients with osteosarcoma who have progressed on at least two prior lines of therapy.

In January 2025, GSK disclosed that the US Food and Drug Administration (FDA) granted Breakthrough Therapy Designation for Ris-Rez being evaluated for the treatment of adult patients with relapsed for refractory osteosarcoma who have progressed on at least two prior lines of therapy.

About Osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor, accounting for 35% of all malignant bone tumors and it has been included in China's “List of Rare Diseases" ^[1]. The median onset age of osteosarcoma is 20 years old, making it the most prevalent primary malignant bone tumor in children and adolescents. Approximately 20-30% of patients who present with localized (non-metastatic) osteosarcoma and 80% of those who present with metastatic osteosarcoma will progress to an advanced stage (recurrence or metastasis) ^[2]. The 5-year survival rate for patients with advanced osteosarcoma is only about 20% ^[3]. Globally, treatment options for relapsed or refractory osteosarcoma following first-line chemotherapy are extremely limited, with no standard of care available ^[4-5], which highlights a significant unmet clinical need.

About Soft Tissue Sarcoma

Soft tissue sarcomas (STS) represent a heterogeneous group of cancers, comprising over 100 distinct histotypes and accounting for less than 1% of all adult solid tumors ^[6]. The primary management strategy for localized disease typically involves surgery, however, despite optimal local treatment, up to 40% of STS patients develop metastatic disease, which often results in fatal progression ^[7]. The standard first-line treatment for STS involves anthracycline-based regimens, which are used across nearly all subtypes and result in a median PFS of approximately six months ^[8]. Upon disease progression, second-line treatments such as gemcitabine, dacarbazine, ifosfamide and target treatment (e.g. Anlotinib, Pazopanib, Regorafenib) are selected based on tumor isotype ^[5]. Upon disease progression following two prior lines of therapy, available therapeutic alternatives dwindle substantially, with an absence of sanctioned treatment options – a reality that underscores a critical gap in patient care.

References

1. Strauss SJ, et al. Ann Oncol. 2021;32(12):1520-1536.

2. Durfee RA, et al. Rheumatol Ther. 2016 Dec;3(2):221-243.

3. Meltzer PS, et al. N Engl J Med. 2021;385(22):2066-2076.

4. National Comprehensive Cancer Network (NCCN). NCCN clinical practice guidelines in oncology (NCCN Guidelines): bone cancer. August 20, 2024. Version 1.2025. Accessed 24 October 2024. 

5. Chinese Society of Clinical Oncology (CSCO). CSCO clinical practice guidelines: bone and soft tissue cancer (2024)

6. Sbaraglia M, et al. Pathologica. 2021;113(2):70–84.

7. Coindre JM, et al. J Clin Oncol. 1996;14(3):869–77.

8. Italiano A, et al. Cancer. 2011;117(5):1049–54.