Monoclonal antibodies (mAbs) target and bind to certain tumour antigens, but these antigens may also be expressed on healthy tissue, according to CytomX, a California-based biotech firm which is developing ‘probody’ therapies through its proprietary platform.
Probodies are fully recombinant, ‘masked’ antibodies which remain inert in healthy cells but become active in the presence of certain disease-associated proteases tumour tissue, offering more specific targeting and fewer toxic side effects.
“The proceeds from this financing will help enable CytomX to advance our proprietary pipeline of Probody Drug Conjugates and Probodies against cancer immunotherapy checkpoint targets towards the clinic,” said CytomX CEO Sean McCarthy, who added the firm was also pursuing Probody applications with bispecific antibodies and engineered T-cell therapies.
The $20m Series C round of financing was led by Pfizer’s investment division, with participation from Third Rock Ventures, Canaan Partners and the Roche Venture Fund.
In June 2013, Pfizer struck a deal to develop and commercialise a number of Probody-Drug Conjugates (PDCs), paying CytomX $25m upfront with a further $610m in regulatory and sales milestones.
In a statement yesterday, Elaine Jones executive director of Venture Capital at Pfizer Venture Investments said the Biopharma giant “has been impressed with the Probody platform” since signing the deal.
“Cytomx’s platform provides an important advance for both antibodies and antibody-drug conjugates, enabling the potential development of novel therapeutics against a broader number of targets while minimising the possibility for on-target toxicity,” she added.
Last year, CytomX forged a PDC pact with ImmunoGen and a discovery and development collaboration with Bristol-Myers Squibb for up to four oncology targets using the Probody platform.