SEATTLE--(BUSINESS WIRE)--Calistoga Pharmaceuticals, Inc., the leader in the development of delta-isoform-selective phosphatidylinositol 3 kinase (PI3K) inhibitors for the treatment of cancer and inflammatory diseases, today announced the initiation of a Phase 2 combination trial of CAL-101, the company’s oral, delta-selective PI3K inhibitor, plus rituximab (Rituxan®) in previously untreated, elderly patients with chronic lymphocytic leukemia (CLL).