PI3Kδ signaling inhibition after treatment with the PI3Kδ inhibitor INCB040093. PI3Kδ and JAK1 inhibition as measured using an in vitro assay from whole blood samples (mononuclear cells) obtained on day 15 of cycle 1 from patients receiving INCB040093 at doses of (A) 100 mg BID, (B) 150 mg BID, and (C) 300 mg QD. No target inhibition was observed predose.