Bristol-Myers Squibb Company and CytomX Therapeutics, Inc., a biopharma company developing investigational Probody therapeutics to treat cancer, have expanded their 2014 strategic collaboration to discover therapies that will include as many as eight additional targets using CytomX’s Probody platform.

Probody therapeutics are designed to leverage unique conditions in the tumor microenvironment to enhance tumor-targeting features of an antibody and reduce drug activity in healthy tissues. Probody therapeutics bind selectively to cells within tumor tissue with reduced binding to healthy tissue, potentially improving or creating a therapeutic window. These therapeutics may also have application in other diseases where proteases are dysregulated in affected tissues.

Under the original collaboration, BMS selected four oncology targets, and to date, has progressed the CTLA-4 Probody therapeutic to Investigational New Drug-enabling studies and the three other programs are in the lead discovery and optimization phase.

BMS will have exclusive worldwide rights to develop and commercialize Probody therapeutics for as many as six additional oncology targets and two non-oncology targets. CytomXwill receive an upfront payment of $200 million and research funding over the course of the research term. CytomX will also be eligible to receive as much as $448 million in future development, regulatory and sales milestones for each collaboration target, as well as royalties on sales.

“CytomX’s Probody platform has enhanced our discovery research as we seek to direct the therapeutic effects of immunotherapy in a more targeted approach against tumors,” said Carl Decicco, Ph.D., head of Discovery, BMS. “We look forward to working more extensively with CytomX on this innovative and potentially disruptive approach in oncology as well as other disease areas.”

“This expanded collaboration with Bristol-Myers Squibb gives CytomX the opportunity to further the reach of our potentially transformational Probody technology and provides us with additional financial and strategic flexibility to build our company,” said Sean McCarthy, D. Phil., president and chief executive officer of CytomX. “With CX-072 in Phase 1/2, and CX-2009 approaching clinical studies, our broad wholly-owned pipeline is poised for initial proof of concept as we aim to reinvent therapeutic antibodies.”