It’s not often that researchers get to report good news for cancer patients, but this week at the San Antonio Breast Cancer Symposium, researchers announced encouraging results from studies of two cancer medications that appeared to keep women’s disease from advancing.
In the first trial of 808 women with advanced breast cancer, an experimental drug from Genentech called pertuzumab stalled patients’ cancer for a median of 18 months when added to standard treatment, compared with a year for patients who got usual treatment alone. Whether or not it improves patients’ survival isn’t clear yet, but the study is ongoing.
Pertuzumab attacks the same target as the cancer drug Herceptin, cells that overproduce a protein known as HER2 that promotes tumor growth. Pertuzumab works in a slightly different, but complementary way, and together the drugs appear to slow down the disease. About 20% to 25% of breast cancers are positive for HER2 — these are the women who might benefit from the new pairing of drugs. “Pertuzumab is a winner,” Dr. Eric Winer of the Dana Farber Cancer Center told the Associated Press. Winer was not affiliated with the study.
The second trial involved Novartis AG’s drug everolimus (Afinitor), which is normally used to suppress the immune system of organ transplant patients. Researchers coupled the drug with an aromatase inhibitor in a trial of 724 women, and the combo slowed progression of metastatic breast cancer by four months, compared with the aromatase inhibitors alone. “These results establish a new standard of care for this group of patients,” Dr. Gabriel Hortobagyi, professor of medicine at MD Anderson Cancer Center and lead author of the study, which was presented at the conference and published in the New England Journal of Medicine, told Medpage Today.
Until now, treating advanced breast cancer has been a game of catch-up, in which doctors cycle through all available hormone therapies in a desperate attempt to stay ahead of the disease. But the latest results suggest that patients may be able to get off that treatment treadmill by adding everolimus, which targets a pathway that cancer cells need to survive. Overall, women getting everolimus had seven months with no disease progression, compared with three in the group that did not get the drug.
Because neither drug combination is yet approved by the Food and Drug Administration for use in treating breast cancer, and pertuzumab is still experimental, additional studies will need to validate the results and show that the drugs can extend survival of patients longer than those that are currently available. Another catch: the drugs are likely to be very expensive, up to $10,000 a month, the AP reports.
Doctors are hopeful that confirmation will come soon. Regarding the everolimus trial, Dr. Vered Stearns, the co-director of the Breast Cancer Program at Johns Hopkins University, told Medpage Today: “The superiority of the combination is statistically and clinically significant and I anticipate that will lead to approval and clinical use within a year or less.”