Bristol-Myers Squibb and CytomX Therapeutics, a biopharmaceutical company developing investigational Probody therapeutics for the treatment of cancer, have announced an expansion of their 2014 strategic collaboration to discover novel therapies that will include up to eight additional targets using CytomX’s proprietary Probody platform.

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

As part of the original collaboration signed in May 2014 to discover, develop and commercialize Probody therapeutics, Bristol-Myers Squibb selected four oncology targets, including CTLA-4. In the collaboration to date, Bristol-Myers Squibb 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.

“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, Bristol-Myers Squibb. “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. “With CX-072 in phase I/II, 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.”

Under the terms of the agreement, CytomX will grant Bristol-Myers Squibb exclusive worldwide rights to develop and commercialize Probody therapeutics for up to six additional oncology targets and two non-oncology targets. Bristol-Myers Squibb will make an upfront payment of $200 million to CytomX and, in addition, will provide research funding over the course of the research term. CytomX will also be eligible to receive up to $448 million in future development, regulatory and sales milestone payments for each collaboration target, as well as tiered royalties from the mid-single digits to low-double digits on net sales of each product commercialized by Bristol-Myers Squibb.