CytomX starts dosing in Phase I/II trial of CX-2009 to treat solid tumours

US-based biopharmaceutical firm CytomX Therapeutics has started dosing patients in a Phase I/II clinical trial (PROCLAIM CX-2009) of CX-2009 for the treatment of patients with select advanced solid tumours.

CX-2009 is a probody drug conjugate (PDC) being developed to target CD-166 antigen expressed in various types of tumours such as breast, endometrial and prostate cancers.

PDC targets the antigen particularly in the tumour microenvironment and delivers a tubulin-destabilising maytansine payload called DM4 to the cancer cells. 

The dose-finding Phase I/II trial will investigate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary anti-tumour activity of CX-2009 as a monotherapy. 

The trial will include subjects with several types of tumours such as non-small cell lung, breast, ovarian, endometrial, cholangiocarcinoma (bile duct cancer), head and neck and castration-resistant prostate cancers. 

"We could potentially treat a number of cancers for which few, if any, treatment options exist."

CytomX Therapeutics president and CEO Sean McCarthy said: "With CX-2009, we are leveraging the high levels of CD-166 on many types of cancer cells despite its presence on normal tissue.

"By targeting CD-166 and localising the activity of the CX-2009 probody therapeutic to the tumour, we could potentially treat a number of cancers for which few, if any, treatment options exist."

The Phase I/II trial is part of the firm’s international modular umbrella clinical trial programme called PROCLAIM designed for development of probody therapeutics.

In 2014, CytomX signed a licence agreement to develop PDCs using its antibody masking technology and tumour-selective protease substrates in conjunction with ImmunoGen’s potent antibody drug conjugate cell-killing agents and engineered linkers.