Combining a targeted drug with hormone therapy could extend survival for some women with advanced breast cancer, according to new trial results.
Women taking the drug palbociclib (Ibrance) alongside hormone therapy lived 7 months longer on average than those taking hormone treatment and a placebo. But statistical tests showed that the results should be treated with caution.
The drug had greater benefits in women whose breast cancer had previously responded to hormone therapy alone. These women lived an average of 10 months longer with the combination treatment than those treated with the hormone therapy, called fulvestrant (Faslodex), and the placebo.
Professor Charles Swanton, Cancer Research UK’s chief clinician, called the findings “very encouraging”.
“Although the treatment gave some people with breast cancer precious extra months, it’s not a cure, and won’t work for everyone,” he said. “So, we need to understand more about breast cancer’s weak spots and exploit them to develop even more effective treatments in the future.”
The results were published in the New England Journal of Medicine and presented at the European Society of Medical Oncology congress in Munich, Germany.
Breast cancers can be grouped based on different molecules that are found on the surface of the cancer cells. This trial involved 521 women whose breast cancer had hormone receptor molecules on their surface but didn’t carry a molecule called HER2. Everyone on the trial had previously taken hormone therapy.
When these breast cancers stop responding to other treatments, women are offered chemotherapy instead, which can often have debilitating side effects.
The trial found that adding palbociclib to the hormone therapy in women with advanced, hormone-sensitive breast cancer might delay their need for chemotherapy.
Women taking the combination treatment started chemotherapy around 18 months after the trial began, compared with 9 months in women taking hormone therapy and the placebo.
In total, 3 years after the study began, 5 in 10 women who received the combination treatment were still alive, compared to 4 in 10 women who received hormone therapy and the placebo.
Turner, et al. (2018) Overall Survival with Palbociclib and Fulvestrant in Advanced Breast Cancer. NEJM. DOI: 10.1056/NEJMoa1810527