A Clinical Study Evaluating the Efficacy and Safety of Disitamab Vedotin Combined With PD-1 Inhibitor and Radiotherapy as Bladder-preserving Therapy in Patients With Localized HER2-high Expressing Muscle-invasive Bladder Urothelial Carcinoma Following Maximal Transurethral Resection

Prior treatment

• Previous treatment with anti-PD-1, anti-PD-L1, and anti-PD-L2, including adjuvant therapy phase;
• Those who have received systemic chemotherapy, radiation therapy, or other anti-tumor treatments (including corticosteroid therapy, immunotherapy) or participated in other clinical studies within 4 weeks before the start of treatment, or have not yet recovered from the previous toxicity (excluding 2nd degree hair loss and 1st degree neurotoxicity);
• Other serious and uncontrollable concomitant diseases that may affect the compliance of the scheme or interfere with the interpretation of the results, including active opportunistic infections or progressive (serious) infections, uncontrollable diabetes, cardiovascular diseases (Grade III or IV heart failure defined by the New York Heart Association classification, Grade II or above heart block, myocardial infarction, unstable arrhythmia or unstable angina pectoris in the past six months, cerebral infarction in three months, etc.) or lung diseases (interstitial pneumonia, obstructive pulmonary disease, and symptomatic bronchospasm history);
• Previously received live vaccination within 4 weeks before the start of treatment;
• Previously received allogeneic hematopoietic stem cell transplantation or solid organ transplantation;
• Significant surgical procedures (excluding diagnostic surgeries or TURBT) performed within the 4 weeks prior to the start of treatment;
• In the past 5 years, have had other malignant tumors that have not been cured, but do not include malignant tumors that have been clearly cured, or curable cancers such as basal or squamous cell carcinoma, localized low-risk prostate cancer, cervical in situ cancer, or breast in situ cancer; Note: Localized low-risk prostate cancer (defined as patients with stage ≤ T2b, Gleason score ≤ 7, and PSA ≤ 20ng/mL (as measured) at the time of prostate cancer diagnosis who have received curative treatment and have no biochemical recurrence of prostate-specific antigen (PSA) may participate in this study);

Other illness

• Individuals known to be allergic to recombinant humanized anti-PD-1 monoclonal antibody drugs and their components;
• Positive HIV test result;
• Active hepatitis B or C patients HBsAg or HBcAb positive individuals were simultaneously detected with HBV DNA copy number positivity (quantitative detection limit is 500IU/ml, or reaching the copy number positivity value detected by the research center); Patients of this type must undergo HBV DNA testing during screening studies; Patients with positive HCV antibody test results are only eligible for this study if their HCV RNA PCR test results are negative;
• Have a clear history of active tuberculosis;
• Active autoimmune diseases that require systematic treatment within the past 2 years (such as the use of disease regulating drugs, corticosteroids, or immunosuppressive drugs), allowing for related alternative treatments (such as thyroid hormone, insulin, or physiological corticosteroid replacement therapy for renal or pituitary dysfunction);
• Individuals with a history of substance abuse and inability to quit, or those with a history of mental disorders;

Lab values

• According to the researcher's perspective, there may be increased risks associated with participating in the study, or other severe, acute, or chronic medical or mental illnesses or laboratory abnormalities that may interfere with the interpretation of the research results.

Other

• Pregnant or lactating women;
• Large amounts of pleural or ascites accompanied by clinical symptoms or requiring symptomatic treatment;
• Simultaneous presence of upper urinary tract urothelial carcinoma (renal pelvis, ureteral urothelial carcinoma);

• Men or women aged ≥ 18 years old;
• ECOG PS:0～1;
• The subjects need to undergo maximum TURBT surgery (no need for secondary resection) and imaging diagnosis. The researchers have determined that MIBC (urothelial carcinoma as the main pathological component\>50%) is present, and plan to undergo radical cystectomy, lymph node dissection, and urinary diversion surgery;
• cT2-T4a N0 M0 （CT/MRI ± PET/CT）;
• Accept maximum TURBT;
• Have tissue examination specimens with TURBT;
• Expected survival period ≥ 3 months;
• The immunohistochemical staining result of the tissue after the last TURBT surgery was IHC 2+or 3+;
• The main organ function is normal (14 days before enrollment), which meets the following criteria:
  • The standard for blood routine examination must meet the following criteria: (no blood transfusion or treatment with granulocyte colony-stimulating factor within 14 days before enrollment):
  • HB≥90 g/L； ANC≥1.5×109 /L； PLT≥100×109 /L；
  • Non functional organic diseases must meet the following criteria:
  • T-BIL ≤ 1.5 × ULN (upper limit of normal value); ALT and AST ≤ 2.5 × ULN; If there is liver metastasis, ALT and AST should be ≤ 5 × ULN; Blood creatinine ≤ 1.5 × ULN or creatinine clearance rate (CrCl) calculated according to the Cockcroft Gault formula ≥ 50 mL/min; International normalized ratio (INR) and activated partial thromboplastin time (aPTT): ≤ 1.5 × ULN (this standard is only applicable to patients who have not received anticoagulant therapy); Patients receiving anticoagulant therapy should ensure that the anticoagulant is within the required treatment range;
• Have not received systemic corticosteroid treatment within 4 weeks prior to treatment;
• Men with reproductive ability or women with the possibility of pregnancy must use highly effective contraceptive methods during the trial (such as oral contraceptives, intrauterine devices, abstinence control or barrier contraception combined with spermicides), and continue contraception for 12 months after the end of treatment;
• The subjects voluntarily joined the study, signed informed consent forms, had good compliance, and cooperated with follow-up.