Amgen and CytomX Therapeutics are set to co-develop a Probody T-cell engaging bispecific against the Epidermal Growth Factor Receptor (EGFR),

The EGFR is a highly-validated oncology target expressed on multiple human cancer types. Probody T-cell engaging bispecifics are antibody constructs capable of directing cytotoxic T-cells in tumour microenvironments. In preclinical studies, CytomX's Probody versions of EGFRxCD3 bispecific therapeutics induced tumour regressions and increased the therapeutic window for EGFR.

Under the terms of the agreement, Amgen and CytomX will co-develop a Probody T-cell engaging bispecific against EGFRxCD3 with CytomX leading early development. Amgen will lead later development and commercialisation with global late-stage development costs shared between the two companies.

Amgen will make an upfront payment of $40 million and purchase $20 million of CytomX common stock. CytomX will be eligible to receive up to $455 million in development, regulatory and commercial milestones for the EGFR program. Amgen will lead global commercial activities with CytomX able to opt into a profit share in the US and receive tiered, double-digit royalties on net product sales outside of the US.

Amgen will also receive exclusive worldwide rights to develop and commercialise up to three additional, undisclosed targets. Should Amgen  pursue all of these targets, CytomX will be eligible to receive up to $950 million in additional upfront and milestone payments and high single-digit to mid-double digit royalty payments on any resulting products. CytomX will also receive the rights from Amgen to an undisclosed preclinical T-cell engaging bispecific programme; Amgen is eligible to receive milestones and royalty payments on any resulting products from this programme.