The purpose of this study is to learn about the safety and effects of the study medicine (Disitamab Vedotin) in people with non-muscle invasive bladder cancer. This study is seeking participants whose bladder cancer is still in early stages, has not spread outside of the bladder, has been removed with surgery, and is high risk. Each participant was assigned to one of two study treatment groups: One group is given Disitamab Vedotin and BCG.The second group is given BCG only and will not receive Disitamab Vedotin.

HERO: A Phase III Randomized Controlled Trial of Disitamab Vedotin (DV) Combined with Bacillus Calmette-Guérin (BCG) in BCG-Naïve Patients with HER2-Expressing, High-Risk Non-Muscle-Invasive Bladder Cancer

This Phase 3, open-label, randomized, controlled clinical trial will enroll approximately 182 patients, who will be assigned in a 1:1 ratio to one of two treatment groups:

Group A: Disitamab Vedotin plus BCG (induction and maintenance therapy)

Group B: BCG alone (induction and maintenance therapy)

The study is designed to demonstrate the superiority of Disitamab Vedotin combined with BCG (during both induction and maintenance phases) over BCG alone in prolonging event-free survival (EFS) among BCG-naïve participants with high-risk, HER2-expressing non-muscle invasive bladder cancer.

Inclusion Criteria

1. Age ≥ 18 years.
2. Histologically confirmed high-risk, non-muscle-invasive urothelial carcinoma of the bladder (UCC) (with >50% urothelial carcinoma as the predominant histological component), defined by the presence of any of the following: a. T1 tumor; b. High-grade Ta tumor; c. Carcinoma in situ (CIS).
3. Complete resection of all Ta/T1 papillary lesions (including patients with concomitant CIS). The most recent Transurethral Resection of Bladder Tumor (TURBT) must have been performed within 12 weeks prior to randomization. A second TURBT was required if indicated per current local applicable guidelines.
4. HER2 expression (IHC 1+/2+/3+) as confirmed by immunohistochemistry (IHC) testing at the local institution's pathology department.
5. Unwillingness or ineligibility to undergo radical cystectomy.
6. Eastern Cooperative Oncology Group (ECOG) performance status (PS) of ≤ 2.
7. Signed informed consent form (ICF).

Exclusion Criteria

1. Histologically confirmed evidence of muscle-invasive (T2 or higher), locally advanced, or metastatic urothelial carcinoma, or the presence of concurrent extravesical non-muscle-invasive urothelial carcinoma.
2. Histopathological findings of pure small cell carcinoma, pure adenocarcinoma, pure squamous cell carcinoma, or pure squamous CIS of the bladder.
3. History of upper tract urothelial carcinoma (except for cases with no recurrence within 2 years following radical treatment for UTUC).
4. Prior therapy with any other type of HER2-targeted inhibitor.
5. Major surgery within 2 weeks prior to randomization.
6. Any other condition that, in the investigator's judgment, would make the patient unsuitable for participation in this study.

Individual Participant Data is protected.