Trial Design: Open-label, international, multicentre window of opportunity phase II trial that aims to evaluate the effects of short-term preoperative therapy with atezolizumab in patients with histologically confirmed (T2-T4a) transitional cell carcinoma of the bladder. Eligible patients will receive 2 x 3 weekly cycles of atezolizumab pre-cystectomy and will be followed up for 2 years post cystectomy to collect survival and disease status data. The efficacy of atezolizumab will be assessed on CT/MRI scan images and tumour tissue samples collected at baseline and after treatment with atezolizumab. ABACUS includes an extensive translational program.
ABACUS met its primary endpoint and study result were reported as an oral abstract at ASCO 2018.
Toxicity and Surgical Complication Rates of Neoadjuvant Atezolizumab in Patients with Muscle-invasive Bladder Cancer Undergoing Radical Cystectomy: Updated Safety Results from the ABACUS Trial. Szabados B, Rodriguez-Vida A, Durán I, et al. Eur Urol Oncol. 2021 Jun;4(3):456-463.
Clinical efficacy and biomarker analysis of neoadjuvant atezolizumab in operable urothelial carcinoma in the ABACUS trial. Powles T, Kockx M, Rodriguez-Vida A, et al. Nat Med. 2019 Nov;25(11):1706-1714.
A phase II study investigating the safety and efficacy of neoadjuvant atezolizumab in muscle invasive bladder cancer (ABACUS). Thomas Powles, Alejo Rodriguez-Vida, Ignacio Duran et al. Journal of Clinical Oncology (2018) 36:15_suppl, 4506 - 4506
Cancer Research UK website A trial looking at MPDL3280A before surgery for bladder cancer (ABACUS)