Immunotherapy breakthrough in treatment of aggressive breast cancers
- Combined with chemotherapy, a new immunotherapy drug has shown promise against hard-to-treat breast cancer. But the benefit for most patients was small
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.
The results were discussed at a cancer conference in Munich, Germany, and published by the New England Journal of Medicine.
Drugs called checkpoint inhibitors have transformed the treatment of many types of cancer by removing a chemical brake that keeps the immune system from killing tumour 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 per cent of cases are this type – their growth is not fuelled by the hormones oestrogen 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 analysing how women fared according to that factor if Tecentriq improved survival overall.