Gilead Sciences is acquiring Calistoga Pharmaceuticals for $375 million. The aim is to broaden its expertise and pipeline in oncology and inflammatory diseases. Calistoga could earn up to an additional $225 million if certain milestones are achieved. Gilead anticipates that the deal will close in the second quarter and plans to finance the acquisition through available cash on hand.
Calistoga is focused on developing compounds that selectively target isoforms of phosphoinositide-3 kinase (PI3K). This pathway has been shown to be a central signaling pathway for cellular proliferation, survival, and trafficking. Calistoga’s pipeline is largely at the preclinical stage, with applications in oncology and inflammation.
The company’s lead product candidate, CAL-101, is reportedly a specific inhibitor of the PI3K delta isoform. PI3K delta is preferentially expressed in leukocytes involved in a variety of inflammatory and autoimmune diseases and hematological cancers. CAL-101 is currently in Phase II studies as a single agent in patients with refractory indolent non-Hodgkin lymphoma and in combination with rituximab in treatment-naïve elderly patients with chronic lymphocytic leukemia.
Commenting on the takeover of Calistoga, Norbert W. Bischofberger, Ph.D., Gilead’s evp R&D and CSO, says, “Building on the recent acquisitions of CGI Pharmaceuticals and Arresto Biosciences, this acquisition serves to further broaden Gilead’s pipeline and expertise in the areas of oncology and inflammation.”
Gilead spent $225 million to buy Arresto Biosciences, which was announced in December 2010. The company develops medicines that target enzymes involved in the synthesis of the extracellular matrix, which appear to play a role in the etiology of a variety of fibrotic diseases and cancer. Lead product AB0024 is a humanized mAb in a Phase I idiopathic pulmonary fibrosis study.
In June 2010, Gilead said that it would pay $120 million for CGI Pharmaceuticals. Gilead thus gained expertise in protein kinase biology and small molecule discovery that it expects to leverage in the development of drugs for inflammatory diseases. It also obtained a library of small molecule kinase inhibitors.