YANTAI, China, June 5, 2023 /PRNewswire/ -- RemeGen Co., Ltd. ("RemeGen" or "the Company") (9995.HK, SHA: 688331), a commercial-stage biotechnology company,  announced the latest clinical research results on disitamab vedotin (RC48) at this year's American Society of Clinical Oncology (ASCO) Annual Meeting, taking place June 2-6, 2023, in Chicago.

Researchers tested disitamab vedotin and toripalimab in combination on patients diagnosed with locally advanced or metastatic urothelial carcinoma (la/mUC). The objective of the study was to determine the safety and efficacy of this treatment approach. A total of 41 la/mUC patients were enrolled in the open-label multicenter trial. Patients were administered different doses of disitamab vedotin and toripalimab every two weeks intravenously as part of the trial. While the primary focus of the study was to evaluate the safety of disitamab vedotin, the researchers also conducted ancillary studies to determine the effectiveness of the treatment in managing urothelial carcinoma, while examining specific biomarkers in the tumor biopsies. This comprehensive approach aimed to gain insights into whether this treatment combination could provide benefits to patients with advanced or metastatic urothelial carcinoma.

The combination of disitamab vedotin and toripalimab showed promising results in patients with advanced or metastatic urothelial carcinoma. No dose-limiting toxicity was observed, and the recommended dose was disitamab vedotin 2mg/kg plus toripalimab 3mg/kg every two weeks. By the cutoff date of Nov. 18, 2022, the confirmed Objective Response Rate (cORR) was 73.2% (95%CI: 57.1, 85.8), including 9.8% Complete Response (CR). In the HER2 IHC 3+/2+ and IHC 1+ subgroups, the confirmed ORRs were noted as 83.3% and 64.3% respectively. The median Duration of Response (mDOR) was observed to be 8.2 months. For treatment-naive patients, the confirmed ORR stood at 76.0%. The Disease Control Rate (DCR) was reported at 90.2% (95% CI, 76.9–97.3). This was coupled with a median Progression-Free Survival (PFS) of 9.2 months (95%CI: 5.7-10.3) and a 2-year Overall Survival (OS) rate of 63.2%.

"Treating locally advanced or metastatic urothelial carcinoma remains a substantial unmet clinical need," stated Professor Guo Jun of Peking University Cancer Hospital, who is also the principal investigator of the study. "In clinical practice, we find that approximately 90% of la/mUC patients show HER2 expression at IHC 1+ or above. It is gratifying to showcase the updated long-term survival data at this year's ASCO Annual Meeting, highlighting the impressive efficacy of disitamab vedotin across varied HER2 or PD-L1 expression levels."

Fang Jianmin, CEO and Chief Scientific Officer of RemeGen, said: "We're thrilled to share updates on disitamab vedotin research at the 2023 ASCO Annual Meeting. The study further underscores the potential of disitamab vedotin, in combination with PD-1 inhibitors, for treating urothelial carcinoma. Currently, we are conducting a prospective phase III study to investigate the safety and efficacy of this combination therapy. The encouraging outcomes seen so far suggest a promising avenue for exploring disitamab vedotin across different indications."

In addition, three of RemeGen's abstracts on the novel antibody drug conjugate were selected for online publication by ASCO and are now available on ASCO's Abstract Titles Released webpage. 

In the first abstract, titled A multicenter, phase Il trial of RC48-ADC combined with radiotherapy, PD-1/L1 inhibitor sequential GM-CSF and sequential IL-2 (PRaG3.0 regimen) for salvage therapy in patients with HER2-expressing advanced solid tumors, disitamab vedotin was found to be effective with fewer side effects when given at a different schedule from once every 2 weeks to once every 3 weeks. This treatment has the potential to improve the sensitivity of patients with HER2-expressing cancers who have already undergone treatment.

In the second abstract, titled The efficacy and safety of antibody drug conjugate for high-risk non-muscle-invasive bladder cancer, disitamab vedotin was administered as a monotherapy or combined with tislelizumab. These treatments were tested on non-muscle-invasive bladder cancer (NMIBC) patients with no history of radical cystectomy and showed efficacy with manageable side effects. This treatment could potentially be a viable option for those with high-risk NMIBC. RemeGen is conducting further research to better understand how disitamab vedotin combined with tislelizumab can further improve the treatment of NMIBC.

The third abstract was titled Assessment of Her2 status in extramammary Paget disease and its implication for disitamab vedotin, a novel humanized anti-HER2 antibody-drug conjugate (ADC) therapy. According to the study, the expression rate of HER-2 was very high in extramammary Paget disease (EMPD), indicating that it may be used as a routine treatment target. Disitamab vedotin showed efficacy in these patients and need further validation.

About RemeGen Co. Ltd.

Founded in 2008, RemeGen (9995.HK, SHA: 688331) is a leading biopharmaceutical company in China committed to providing solutions to the unmet clinical needs of patients suffering from life-threatening illnesses. RemeGen has research laboratories and offices throughout China and the United States. The company is committed to discovering, developing, and commercializing innovative and differentiated biologic drugs of significant clinical value in the key therapeutic areas of autoimmune, oncology, and ophthalmic diseases.

About Disitamab Vedotin (RC48-ADC)

Disitamab vedotin (RC48-ADC) is an investigational anti-HER2 antibody-drug conjugate targeting prevalent cancers with significant unmet medical needs and is the first domestically developed ADC to receive marketing approval in China. The drug was granted conditional marketing approval in June 2021 by the National Medical Products Administration (NMPA) in China to treat locally advanced or metastatic gastric cancer. In the same month, the company submitted an Investigational New Drug (IND) application for the treatment of HER2-expressing advanced or metastatic urothelial carcinoma with disitamab vedotin. In 2021, RemeGen and Seagen Inc. entered into an exclusive license agreement to develop and commercialize disitamab vedotin in all countries outside of RemeGen's territory of Asia, excluding Japan and Singapore .

The company is implementing a differentiated development and commercial strategy for disitamab vedotin, including (i) gastric cancer (GC), (ii) urothelial carcinoma (UC), (iii) breast cancer (BC), and (iv) other HER2-expressing cancers.