AACR 2019 Snapshot: A First Look at Predictive Biomarker Data from a Combination Study of Pelareorep + Keytruda® in Pancreatic Cancer
AACR 2019 was an important conference for us. We’ve been investigating the potential utility of a biomarker to help predict a patients response to receiving pelareorep combined with other immunotherapies, such as checkpoint inhibitors. This study is a first look at the utility of T cell clonality as a predictor of response to therapy, and we’re very excited about it.
Of 11 patients with pancreatic cancer treated in a phase 1b study of pelareorep combined with Merck’s checkpoint inhibitor, Keytruda®, T cell clone expansion and low T cell diversity was clearly correlated with improved overall survival. This helps confirm our hypothesis that pelareorep does indeed induce T cell expansion and also suggests that a simple blood draw could be used to predict treatment response.
Our findings have significant implications for the multiple programs in our pipeline. In the short term, this biomarker is being confirmed in our development programs and could accelerate future clinical trials of pelareorep by identifying patients most likely to respond to treatment, both predictively and prognostically. We expect T cell clonality will be a biomarker in our phase 3 registration study in metastatic breast cancer, and it could potentially cut the number of patients needed in the trial from 450 to under 300, as well as shorten the duration of the study by as much as 9 – 12 months.