How Genentech Engineered Antibodies to Starve Tumors of Blood

A 2007 Genentech patent describing specific lab-made antibodies that block a protein called VEGF, which tumors use to grow new blood vessels.

What it covers

This patent describes a humanized antibody designed to bind tightly to Vascular Endothelial Growth Factor (VEGF). VEGF is a protein that signals the body to grow new blood vessels. By blocking this signal, the antibody prevents tumors from building the blood supply they need to expand. The patent specifically claims the precise amino acid sequences for the antibody's 'variable domains'—the parts that actually grab onto the VEGF protein—ensuring it binds with high affinity.

What it doesn't cover

• —Does not cover antibodies that bind to targets other than VEGF.
• —Does not cover naturally occurring, non-humanized antibodies.
• —Does not cover therapeutic methods of treating patients, only the antibody composition itself.
• —Does not cover antibody sequences that fall outside the specific amino acid variations defined in the claims.

The clever bit

The inventors used 'humanization' to make a mouse-derived antibody look like a human protein to our immune system, preventing the body from attacking the medicine while maintaining the high-affinity binding of the original mouse version.

Why it matters

This technology is the foundation for anti-angiogenic therapy, a major pillar of modern oncology. By cutting off the nutrient supply to tumors, these antibodies transformed cancer treatment from purely cytotoxic (killing cells) to targeted biological intervention. It paved the way for drugs like bevacizumab, which have been used to treat various cancers and eye diseases.

Real-world examples

• 1.Avastin (bevacizumab)
• 2.Lucentis (ranibizumab)