Updated results from the pivotal phase II study, IMvigor 210, of the investigational cancer immunotherapy Atezolizumab ( MPDL3280A ) in people with locally advanced or metastatic urothelial carcinoma ( mUC ) were presented at the 2016 Genitourinary Cancers Symposium of the American Society of Clinical Oncology ( ASCO GU ).
Median overall survival ( mOS ) in this heavily pre-treated population was 11.4 months [ 95% CI: 9.0, NE ] in people with higher levels of PD-L1 expression, and 7.9 months [ 95% CI: 6.6, 9.3 ] in the overall study population.
The study also showed that 84% ( n=38/45 ) of people who responded to Atezolizumab continued to respond regardless of their PD-L1 status, when the results were assessed with longer median follow-up of 11.7 months.
Median duration of response has not yet been reached.
Atezolizumab was well tolerated and adverse events were consistent with those observed in previous updates.
IMvigor 210 is an open-label, multicentre, single-arm phase II study that evaluated the safety and efficacy of Atezolizumab in people with locally advanced or mUC, regardless of PD-L1 expression.
People in the study were enrolled into one of two cohorts.
Cohort 1 comprised those who had received no prior therapies for locally advanced or mUC, but who were ineligible for first-line Cisplatin-based therapy. The results for this cohort are not yet mature.
Cohort 2, for which updated results were announced, included people whose disease had progressed during or following previous treatment with a Platinum-based chemotherapy regimen ( heavily pretreated ), 41% of people in the study had 2 or more treatments in the metastatic setting. People received a 1200-mg intravenous dose of Atezolizumab on day 1 of 21-day cycles until progressive disease ( Cohort 1 ) or loss of clinical benefit ( Cohort 2 ).
Co-primary endpoints of the study included confirmed RECIST v1.1 ORR per central IRF and investigator-assessed modified RECIST ORR.
Secondary endpoints included duration of response, overall survival, progression-free survival and safety.
People were selected by histology, prior lines of therapy and PD-L1 expression on tumour-infiltrating immune cells ( IC ), using an investigational immunohistochemistry test that is being developed by Roche Tissue Diagnostics.
Atezolizumab is an investigational monoclonal antibody designed to target and bind to a protein called PD-L1, which is expressed on tumour cells ( TCs ) and tumour-infiltrating immune cells ( ICs ).
PD-L1 interacts with PD-1 and B7.1, both found on the surface of T cells, causing inhibition of T cells. By blocking this interaction, Atezolizumab may enable the activation of T cells, restoring their ability to effectively detect and attack tumour cells. ( Xagena )
Source: Roche, 2016