A once-a-day breast cancer pill has won approval from the FDA thanks in part to clinical trials conducted by Israeli researchers. On Tuesday, GlaxoSmithKline won US approval for the pill – called Tykerb – that the drug maker hopes will launch a new era in oncology.

The FDA approved Tykerb, in combination with chemotherapy agent Xeloda, for women with metastatic or advanced breast cancer who carry the HER2 gene, and who have failed to respond to treatment with Herceptin, a rival product from Roche and Genentech.

Last year, over 300 women from medical centers around Israel, the United States, and Europe took part in trials for the drug. Dr. Bella Kaufmann, director of the breast cancer unit at the cancer research center at Tel Aviv’s Sheba Medical Center coordinated the research program including Israeli women. Other Israeli medical facilities taking part in the trial included Ichilov hospital in Tel Aviv, and Kaplan Hospital in Rehovot.

Reporting at the annual meeting of the European Society for Medical Oncology in Turkey late last year, Kaufman reported on the findings, telling colleagues that Tykerb helps women with relapsing inflammatory breast cancer. About 1% to 3% of women in the US develop the condition, although rates are higher among African-Americans – about 10%.

“It may be the most lethal form of breast cancer and there are few treatment options,” Kaufman told WebMD. “More than one-third of women have metastatic disease (cancer that has spread to other parts of the body) at the time of diagnosis, and only 40% of women are still alive three years later.”

She explained that Tykerb targets a tumor’s genetic roots, specifically two related proteins – HER2 and EGFR – that sit on the surface of inflammatory breast cancer cells and play a critical role in the growth and spread of cancer. They have a direct effect on cancer cells, stimulating the cells to proliferate, migrate, and metastasize. Tykerb attaches to the proteins, thereby blocking their action, and slowing or stopping the growth of tumor cells.

Kaufman and the Israeli researchers studied two groups of women: 32 women whose tumors had high levels of HER2 and 15 women whose tumors had high levels of EGFR but not HER2. All took one Tykerb pill once a day for at least 56 days.
Results showed that tumors shrank or stopped growing in half of the women with high HER2 levels. Seven percent of the women with high levels of EGFR but not HER2 had a similar response.

The drug was generally well tolerated. Side effects included mild skin rashes and diarrhea that could be easily managed with over-the-counter medications.

According to Kaufman, Tykerb can offer a new, highly targeted approach to fighting highly lethal breast tumors with few side effects.

After the announcement of the approval of Tykerb by the FDA, Kaufman said yesterday, “We’ve opened a new era in the struggle against breast cancer. Tykerb establishes the basis for the continued improvement in the quality of patients’ lives, focusing on changing the rate of survival from breast cancer in Israel and in the world in the next decade. We’ll already begin to see the change in the near future.”

Tykerb will be available in the US within two weeks.