-Achievement of clinical candidate is the first in the multi-target collaboration and triggers a $5 million milestone payment to CytomX-

-CytomX-retained US co-commercialization and economic rights for select programs-

SOUTH SAN FRANCISCO, CA, USA I January 26, 2023 I CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of conditionally activated, localized biologics, today announced that it achieved a clinical candidate milestone under its TCB agreement with Astellas. The clinical candidate is the first Probody® TCB molecule to progress in the collaboration and will trigger a $5 million dollar milestone payment to CytomX. CytomX and Astellas are also collaborating on additional conditionally activated TCB programs with CytomX eligible to receive future preclinical, clinical and commercial milestones. CytomX retains a cost share and co-commercialization option on a select number of targets.

“We are pleased with the achievement of the first Probody® TCB clinical candidate in our collaboration with Astellas and that our discovery and research capabilities in this important modality continue to deliver next-generation, localized drug candidates. We look forward to continuing to partner with Astellas in advancing novel TCBs towards the clinic and potentially making a significant contribution in bringing the power of T-cell engaging therapies to a broader set of patients with cancer,” said Dr. Marcia P. Belvin, Ph.D., senior vice president and head of research at CytomX.

“The progress with Astellas highlights our strategy to create value through a broad, diversified pipeline of wholly-owned and partnered therapeutic programs as well as expanding our research and development efforts in the field of TCBs. T-cell engaging therapies hold tremendous promise; however, the potency of this modality can lead to widespread activation of the immune system and a narrow therapeutic window. Localizing T-cell activity to the tumor microenvironment could result in important breakthroughs for patients, and the Probody® platform has potential to address this challenge,” said Sean McCarthy, D.Phil., chief executive officer and chairman of CytomX Therapeutics.

About CytomX Therapeutics
CytomX is a clinical-stage, oncology-focused biopharmaceutical company dedicated to destroying cancer differently. By pioneering a novel class of conditionally activated biologics, powered by its Probody® technology platform, CytomX’s goal is to transcend the limits of current cancer treatments. CytomX’s robust and differentiated pipeline comprises seven therapeutic candidates across multiple treatment modalities including antibody-drug conjugates (“ADCs”), T-cell engaging bispecific antibodies (“TCBs”), and immune modulators such as cytokines and checkpoint inhibitors (“CPIs”). CX-2029 is an investigational conditionally activated antibody-drug conjugate (ADC) directed toward CD71 and is being developed in collaboration with AbbVie. CytomX’s clinical pipeline also includes cancer immunotherapeutic candidates against validated targets such as the CTLA-4-targeting Probody therapeutics, BMS-986249 and BMS-986288, partnered with Bristol Myers Squibb, as well as CX-904, a conditionally activated T-cell-engaging bispecific antibody targeting the epidermal growth factor receptor (EGFR) on tumor cells and the CD3 receptor on T cells, which is partnered with Amgen. In addition, CytomX has a diverse preclinical portfolio of wholly-owned assets including CX-801, an interferon alpha-2b Probody cytokine that has broad potential applicability in traditionally immuno-oncology sensitive as well as insensitive (cold) tumors and CX-2051, a conditionally activated ADC directed toward EpCAM, with potential applicability across multiple EpCAM-expressing epithelial cancers. CytomX has also established strategic collaborations with multiple leaders in oncology, including AbbVie, Amgen, Astellas, Bristol Myers Squibb, Regeneron and Moderna. For more information about CytomX and how it is working to make conditionally activated treatments the new standard-of-care in the fight against cancer, visit www.cytomx.com and follow us on LinkedIn and Twitter.

SOURCE: CytomX Pharmaceuticals