Efficacy and safety of Bladder Preservation Therapy in combination with Atezolizumab and Radiation Therapy (BPT-ART) for invasive bladder cancer: Interim analysis from a multicenter, open-label, prospective phase II trial
Mené entre 2019 et 2021 sur 45 patients atteints d'un cancer de la vessie de type T2-3 ou T1 à très haut risque de récidive et n'étant pas éligibles ou refusant une cystectomie radicale, cet essai multicentrique de phase II évalue l'efficacité, du point de vue du taux de réponse pathologique complète, et la sécurité d'un traitement de préservation vésicale associant radiothérapie et atézolizumab
PURPOSE: To evaluate the safety and pathological complete response (pCR) rate of radiotherapy with atezolizumab as bladder-preserving therapy for invasive bladder cancer. PATIENTS AND METHODS: A multicenter, phase II study was conducted with clinically T2-3 or very high-risk T1 bladder cancer patients who were poor candidates for or refused radical cystectomy. Here, we report our interim analysis of pCR as a key secondary endpoint ahead of the progression-free survival rate primary endpoint. Radiotherapy (41.4 Gy to the small pelvic field and 16.2 Gy to the whole bladder) was given plus 1200 mg intravenous atezolizumab every 3 weeks. After 24 treatment weeks, response was assessed after transurethral resection and tumor programmed cell death ligand-1(PD-L1) expression was assessed using tumor-infiltrating immune cell scores. RESULTS: Forty-five patients enrolled from January 2019 to May 2021 were analyzed. The most common clinical T stage was T2 (73.3%), followed by T1 (15.6%) and T3 (11.1%). Most tumors were solitary (77.8%), small (<3 cm) (57.8%), and without concurrent carcinoma in situ (88.9%). Thirty-eight patients (84.4%) achieved pCR. High pCR rates were achieved in older patients (90.9%) and in patients with high PD-L1-expressing tumors (95.8% vs. 71.4%). Adverse events (AEs) occurred in 93.3% of patients, with diarrhea being the most common (55.6%), followed by frequent urination (42.2%) and dysuria (20.0%). The frequency of grade 3 AEs was 13.3% while no grade 4 AEs were observed. CONCLUSION: Combination therapy with radiotherapy and atezolizumab provides high pCR rates and acceptable toxicity, indicating it could be a promising option for bladder preservation therapy.
International Journal of Radiation Oncology, Biology, Physics 2023