Immunotherapy scores a first win against some breast cancers
For the first time, one of the new immunotherapy drugs has shown promise against breast cancer in a large study that combined it with chemotherapy to treat an aggressive form of the disease. But the benefit for most women was small, raising questions about whether the treatment is worth its high cost and side effects.
Results were discussed Saturday at a cancer conference in Munich and published by the New England Journal of Medicine.
Drugs called checkpoint inhibitors have transformed treatment of many types of cancer by removing a chemical brake that keeps the immune system from killing tumor cells. Their discovery recently earned scientists a Nobel Prize. Until now, though, they haven’t proved valuable against breast cancer.
The new study tested one from Roche called Tecentriq plus chemo versus chemo alone in 902 women with advanced triple-negative breast cancer. About 15 percent of cases are this type — their growth is not fueled by the hormones estrogen or progesterone, or the gene that Herceptin targets, making them hard to treat.
Women in the study who received Tecentriq plus chemo went two months longer on average without their cancer worsening compared with those on chemo alone — a modest benefit. The combo did not significantly improve survival in an early look before long-term follow-up is complete.
Previous studies found that immunotherapies work best in patients with high levels of a protein that the drugs target, and the plan for the breast cancer study called for analyzing how women fared according to that factor if Tecentriq improved survival overall.
The drug failed that test, but researchers still looked at protein-level results and saw encouraging signs. Women with high levels who received the combo treatment lived roughly 25 months on average versus about 15 months for women given chemo alone.