Neoadjuvant RC48 Plus Gemcitabine in HER2-Expressing MIBC

Condition(s) studied

Investigational drug(s) / intervention(s)

Gemcitabine: On Day 2 of each neoadjuvant therapy cycle, a dose of 1000 mg/m² is administered via intravenous infusion. The regimen is administered every 2 weeks (Q2W).

Toripalimab: On Day 2 of each neoadjuvant therapy cycle, a dose of 3 mg/kg is administered via intravenous infusion. The regimen is administered every 2 weeks (Q2W).

Disitamab Vedotin (RC48): On Day 1 of each neoadjuvant therapy cycle, a dose of 2 mg/kg is administered via intravenous infusion over 30-60 minutes.

Radical Cystectomy: Patients are scheduled to undergo radical cystectomy (RC) within 4 weeks after the last dose of neoadjuvant therapy, and the postoperative specimens will be assessed for pathological response.

Study summary

Objectives: To evaluate the non-inferiority of disitamab vedotin plus gemcitabine versus disitamab vedotin plus toripalimab in terms of the pathological complete response (pCR) rate as neoadjuvant therapy for muscle-invasive bladder cancer (MIBC).

This study is designed to evaluate two parallel neoadjuvant treatment strategies followed by definitive local therapy and adjuvant treatment. Eligible patients will be assigned to either the Experimental Arm, receiving neoadjuvant Disitamab Vedotin (RC48) combined with Gemcitabine, or the Active Comparator Arm, receiving neoadjuvant RC48 combined with Toripalimab. Both neoadjuvant regimens are administered every two weeks for 3 to 6 cycles, contingent upon imaging-based tumor response. Following the neoadjuvant phase, patients from both arms will proceed to receive standard Radical Cystectomy (RC) combined with Pelvic Lymph Node Dissection (PLND) within four weeks of their final dose, with a trimodality therapy (TMT) bladder-sparing approach strictly restricted to a selected minority of patients. In the postoperative phase, eligible patients will receive adjuvant therapy consisting of RC48 plus Toripalimab for 6 cycles, followed by Toripalimab maintenance monotherapy for a duration of ≤ 1 year (or a maximum of 1 year).Patients post-RC require abdominopelvic/chest imaging q3-6m; non-RC patients need cystoscopy q3m and abdominopelvic/chest CT q3-6m. Follow-up staff should proactively contact patients q3m to record imaging findings and inquire about hematuria, stomal lesions, cough/chest pain, CNS symptoms, and accurately document recurrence/progression, metastasis, death with dates.

Eligibility

Primary outcome measure(s)

• Pathological Complete Response (pCR) — Within 1 week after completion of radical cystectomy.
  Defined as the absence of residual viable tumor cells (ypT0N0) in RC+PLND specimens. Assessed post-surgery. Method: A central pathology review committee performs centralized, blinded independent review of slides from all eligible patients. Sites ship de-identified slides and clinical forms to a central lab for uniform anonymization, QC, H\&E staining, and supplementary IHC if needed. All materials are fully de-identified, presented in random order without clinical data. Two senior uropathologists (associate professor level or above) read independently; consensus is final, otherwise a third senior pathologist adjudicates blindly. ypT and ypN are recorded.

Trial sites (22)

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