The treatment of muscle-invasive urothelial carcinoma (MIUC) with adjuvant atezolizumab did not improve disease-free survival (DFS) compared with observation, according to results of the phase 3 IMvigor010 trial published in The Lancet Oncology.
MIUC is associated with a high recurrence rate despite standard therapy. The aim of this trial was to determine if adjuvant atezolizumab improved DFS.
The open-label, phase 3 IMvigor010 trial (ClinicalTrials.gov Identifier: NCT02450331) randomly assigned 809 patients with MIUC to receive adjuvant atezolizumab (n=406) or observation only (n=403).
All patients underwent radical cystectomy or nephroureterectomy with lymph node dissection plus neoadjuvant chemotherapy for stage ypT2-4a or ypN+ tumors.
The primary endpoint was DFS in the intention-to-treat population. At a median follow-up of 21.9 months, DFS was similar between the atezolizumab and observation-only groups.
The median DFS was 19.4 months in the atezolizumab group and 16.6 months in the observation-only group (hazard ratio [HR], 0.89; 95% CI, 0.74-1.08; P =.24). Most subgroups favored observation, including the subgroup with a high PD-L1 expression level.
The median overall survival was not reached in either group, with a 12-month rate of 88% and 81% in the atezolizumab and observation groups, respectively.
Grade 3 or 4 treatment-related adverse events occurred in 16% of patients in the atezolizumab group, with the most common being arthralgia, increased alanine aminotransferase, and colitis. Treatment discontinuation due to an adverse event occurred in 16% of patients.
“The trial did not meet its primary endpoint of improved [DFS] in the atezolizumab group over observation,” the authors concluded. “These data do not support the use of adjuvant checkpoint inhibitor therapy in the setting evaluated in IMvigor010 at this time.”
Disclosures: This research was supported by F Hoffmann-La Roche/Genentech. All of the study authors declared an affiliation with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Bellmunt J, Hussain M, Gschwend JE, et al. Adjuvant atezolizumab versus observation in muscle-invasive urothelial carcinoma (IMvigor010): a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol. 2021;22(4):525-537. doi:10.1016/S1470-2045(21)00004-8