Drug
“smart bombs” are the future of breast cancer
therapy

Using combinations of "smart bomb" cancer drugs that target specific proteins and avoid the indiscriminate cell destruction of chemotherapy may be the wave of the future for cancer patients, experts say.

Early studies show that combining targeted treatments such as Genentech's breast cancer drug Herceptin with GlaxoSmithKline's experimental treatment Tykerb may be helpful in patients who do not respond to Herceptin alone, said Jose Baselga, chief of medical oncology service at Vall d'Hebron University Hospital in Barcelona, Spain.

Targeted therapies act like smart bombs by crippling or knocking out deadly cancer cells while leaving healthy cells intact, unlike the scorched earth approach of chemotherapy which kills both healthy and unhealthy cells.

Using Herceptin and Tykerb together is just one of many drug combinations that could improve on results seen with existing targeted therapies such as ImClone Systems' colon cancer drug Erbitux and OSI Pharmaceuticals' lung cancer drug Tarceva.

"All the chemical models suggest that combinations will be superior, though the data still has to prove it," Baselga said at the annual meeting of the American Society of Clinical Oncology.

Investigators on Saturday released promising results from a mid-stage trial on lung cancer patients of Pfizer's kidney cancer drug Sutent. Now they are planning to test it in combination with Tarceva.

"Most of us feel that except for in very rare instances, tumors are driven by multiple pathways and therefore it makes sense that a multitargeted approach makes most sense," said Mark Socinski, associate professor of medicine at the University of North Carolina at Chapel Hill.

The first targeted therapies isolated single targets. Genentech's Avastin targets a protein known as vascular endothelial growth factor (VEGF), which cuts off the oxygen and nutrients tumors need to survive. Erbitux attacks the epidermal growth factor receptor (EGFR), which curtails tumor growth.

But drugs such as Sutent hit multiple targets, as does Bayer and Onyx Pharmaceuticals' kidney cancer drug Nexavar.

In the colorectal field, behind Avastin and Erbitux, comes Amgen's panitumumab, which has not yet been approved.

"The compelling argument for panitumumab is that it is multitargeting whereas Avastin only targets VEGF and Erbitux only targets EGFR," said William Li, head of the Angiogenesis Foundation. "This raises the exciting possibility that it might have better coverage and could be a competitor to both." (Reuters)