RC48-ADC in Adjuvant/Salvage Treatment of HER2 Positive Non-muscle-invasive Bladder Cancer

Inclusion Criteria: Be willing and able to provide written informed consent/assent for the trial. Life expectancy ≥12 weeks. Have a histologically-confirmed diagnosis of high-risk non-muscle-invasive (according to 2023 NCCN guidelines for bladder cancer) transitional cell carcinoma of the bladder. Subjects with tumors of mixed transitional/non-transitional cell histology are allowed, but transitional cell carcinoma must be the predominant histology. Have been treated with adequate BCG therapy and failed (according to 2023 EAU guidelines for NMIBC, for salvage treatment arm). Have elected not to undergo, or are considered ineligible for radical cystectomy, as determined by the treating surgeon. Have tumor tissues for HER2 IHC evaluation and have a HER2 expression score of HER2 2+ or HER2 3+ reviewed by an independent pathologist at the central laboratory. Have a performance status of 0, 1 or 2 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale. Demonstrate adequate organ function. Female subjects of childbearing potential must have a negative urine or serum pregnancy test within 7 days prior to receiving the first dose of study medication. Male subjects of childbearing potential (Section 5.7.2) must agree to use an adequate method of contraception starting with the first dose of study therapy through 6 months after the last dose of study therapy. Exclusion Criteria: Has muscle-invasive (i.e. T2, T3, T4) locally advanced non-resectable or metastatic urothelial carcinoma. Has concurrent extra-vesical (i.e. urethra, ureter or renal pelvis) non-muscle invasive transitional cell carcinoma of the urothelium. Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks of the first dose of treatment. Has undergone any intervening intravesical chemotherapy or immunotherapy from the time of most recent cystoscopy/TURBT to starting trial treatment. (Note: A single dose of intravesical treatment given as part of the most recent cystoscopy/TURBT, during the screening period, such as with chemotherapy as per local / regional practices, is acceptable.). Allergic to study therapy. Has a known additional malignancy that has had progression or has required active treatment in the last five years. Has an active autoimmune disease that has required systemic treatment in past 2 years. Have diseases that may interfere with the study treatment or severe and uncontrolled concomitant diseases. Has had an allogeneic tissue/solid organ transplant.