Bladder-Preserving Combined-Modality Therapy for Localized Muscle-Invasive Bladder Cancer
Posted: Wednesday, July 7, 2021
Xavier Garcia del Muro, MD, PhD, of the Institut Català d’Oncologia L’Hospitalet del Llobregat, Barcelona, and colleagues evaluated the feasibility, toxicity, and activity of the monoclonal antibodies durvalumab plus tremelimumab with concurrent radiotherapy in patients with localized muscle-invasive bladder cancer. During the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4505), these researchers reported their findings from the multicenter phase II IMMUNOPRESERVE-SOGUG trial, indicating this bladder-preserving combined-modality approach appears feasible and safe with high efficacy in these individuals.
“Bladder-preserving combined-modality therapies constitute an alternative to radical cystectomy for selected patients,” the investigators commented. “In preclinical studies, [the] combination of radiation [therapy] and dual checkpoint blockade appears to activate nonredundant immune mechanisms, potentiating antitumor activity.”
A total of 32 patients underwent transurethral resection of the tumor, followed by treatment with 1,500 mg of durvalumab plus 75 mg of tremelimumab every 4 weeks for three doses. After 2 weeks, normofractionated external-beam radiotherapy was initiated at doses of 46 Gy to the minor pelvis and 64 to 66 Gy to the bladder. Salvage cystectomy was offered to patients with either residual or relapsed disease.
The majority of patients (81%) achieved a complete response, based on tumor site biopsy after treatment. Two patients underwent salvage cystectomy because of muscle-invasive bladder cancer and T1 relapses, respectively, after a median follow-up of 6.1 months. The estimated rates of disease-free survival with an intact bladder, disease-free survival, and overall survival at 6 months were 76%, 80%, and 93%, respectively.
Nearly all patients (97%) experienced adverse events related to radiotherapy and/or immunotherapy; diarrhea (41%) and urinary disorders (37.5%) were reported most frequently. More than a quarter of patients (31%) experienced grade 3 or 4 treatment-related adverse events; gastrointestinal toxicity (12.5%), acute kidney failure (6%), and hepatitis (6%) were most frequent among this population.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.