(HealthDay News) — Adding palbociclib (Ibrance) to standard hormone therapy may benefit patients with advanced hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2−) breast cancer over hormone therapy alone, according to a new study. The findings were published online May 30 in the New England Journal of Medicine to coincide with presentation at the annual meeting of the American Society of Clinical Oncology, held from May 29 to June 2 in Chicago.
Nicholas Turner, MD, PhD, of the Institute of Cancer Research in London, and colleagues randomly assigned 521 women (median age, 57 years) to receive either palbociclib plus the standard hormone therapy fulvestrant, or fulvestrant with a placebo pill. All of the study participants had advanced HR+/HER2− breast cancer and worsened or relapsed after they had taken initial hormone therapy. The researchers assessed progression-free survival.
The average time to progression in the palbociclib/fulvestrant group was 9.2 months, compared to 3.8 months in the fulvestrant-alone group, the investigators found. Adding palbociclib was so effective that the trial was stopped early so that those who were in the control group could also be offered the medication. Patients taking the combination treatment had a small increase in fatigue, hair thinning, and mouth soreness compared to the solo-therapy group, Turner told HealthDay. They were also more likely to get infections. Only a few women dropped out due to side effects.
A longer follow-up is needed to see the effect of the medication on the women’s overall survival, not just keeping the cancer under control, Turner said. The researchers are also studying the possibility of using palbociclib in women with early-stage HR+ breast cancer.
The study was funded in part by Pfizer, the manufacturer of palbociclib.