R84 is a selective, fully human monoclonal antibody that blocks the cancer-promoting agent vascular endothelial growth factor.
The study results showed that tumor-associated macrophages are reduced after R84 therapy. In addition, the data showed that when given for a prolonged period, R84 decreased microvessel density and expression of VEGFR2, demonstrating that the antibody is acting to reduce VEGF-induced angiogenesis in tumor tissue.
Treatment with R84 reduced the growth of well-established breast tumors by 55%, equivalent to the reduction achieved with Avastin. The researchers also demonstrated that R84 and Avastin were equally effective at controlling tumor growth in a preclinical model of sarcoma. In every preclinical tumor model evaluated thus far, the anti-tumor activity of R84 has been comparable to that of Avastin.
Peregrine in association with Affitech has filed a patent application for R84 with the US Patent and Trademark Office to preserve the right to obtain patent protection in the US, EU and the rest of the world.
Steven King, president and CEO of Peregrine, said: “We are delighted that R84 is generating similar, and potentially superior, results in preclinical cancer models. As a result of these positive developments, we are initiating additional preclinical studies to advance R84 as our next potential clinical candidate.”