In a Swiss phase II trial (SAKK 06/19) reported at the 2026 ASCO Annual Meeting (Abstract 4503) and published in the Journal of Clinical Oncology, Cathomas et al found that the addition of intravesical recombinant bacillus Calmette-Guérin (rBCG) to perioperative chemoimmunotherapy was associated with high rates of pathologic complete response and pathologic overall response in patients with muscle-invasive bladder cancer (MIBC).
Study Details
In the multicenter study, 47 patients eligible for cisplatin and radical cystectomy with lymph node dissection (RC-LND) were enrolled between April 2022 and April 2025. Patients received rBCG instilled intravesically on days 1, 8, and 15. Atezolizumab was initiated on day 1 concurrently with rBCG and was repeated every 3 weeks for a total of four doses. Chemotherapy was started on day 22 and consisted of four cycles of gemcitabine and cisplatin every 3 weeks. RC-LND had to be performed within 4 to 8 weeks after completion of the last chemotherapy cycle. Adjuvant therapy with atezolizumab (every 3 weeks for 13 cycles) was administered only in patients with > ypT1 ypN0.
Key Findings
Among the 47 patients, 7 did not undergo RC-LND, with 6 declining and 1 being deemed unfit for surgery.
rBCG was instilled in 95% of patients, with 78% receiving all three doses. On central review, pathologic complete response was achieved in 27 (68%) of 40 patients (one-sided 95% confidence interval [CI] = 53%). Pathologic overall response was achieved in 33 (83%) of 40 patients (95% CI = 67%–93%).
At time of analysis, 12-month event-free survival was 90% (95% CI = 76%–96%) and 12-month overall survival was 96% (95% CI = 84%–99%).
Treatment-related adverse events of any grade, grade 3, and grade 4 occurred for 42%, 9%, and 0% of patients receiving rBCG; 55%, 15%, and 2% receiving atezolizumab; and 96%, 38%, and 17% receiving chemotherapy. One patient died as a result of surgery.
The investigators concluded: “To our knowledge, this is the first trial combining intravesical rBCG with chemoimmunotherapy in MIBC, demonstrating high [pathologic complete response and pathologic overall response] rates that warrant further investigation in prospective randomized trials.”
Richard Cathomas, MD, of Division of Oncology/Hematology, Kantonsspital Graübunden, Chur, Switzerland, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was supported by Roche. For full disclosures of the study authors, visit ascopubs.org.
