Combining the newly developed drug palbociclib with hormone therapy substantially extends the lives of women with advanced breast cancer. The study was presented at the European Society of Medical Oncology congress in Munich, Germany.
The Guardian reports scientists have announced that women with metastatic cancer who were given the combination therapy lived seven months longer than those who were treated with hormones alone. And in women who had previously responded to hormone therapy, these extended survival times reached an average of 10 months.
“These results indicate that we can now offer women with incurable breast cancer some precious extra survival time before their condition worsens. It is very encouraging,” said Professor Nick Turner of the Institute of Cancer Research, who led the study.
The report says researchers from the Royal Marsden NHS Foundation Trust were also involved in the study, which was funded by the drug’s manufacturer, Pfizer. A total of 521 women with advanced, hormone-sensitive breast cancer took part.
The trial examined what effect palbociclib had on women’s overall survival rates when their advanced breast cancer stopped responding to other treatments. Usually the only option then available is chemotherapy, which can have debilitating side-effects. The researchers sought to find out if the drug could delay the need for chemotherapy.
The report says their analysis revealed that women who received the combination treatment survived for an average of 34.9 months – 6.9 months longer than those who received only hormone treatment. Three years after they were enrolled in the study, 49.6% of women who received both palbociclib and hormones were still alive, compared with 40.8% of women who were treated with hormones alone.
However, Baroness Delyth Morgan, CEO of Breast Cancer Now – while welcoming the study – said she was concerned that the new treatment might not reach National Health Service (NHS) breast cancer patients because its appraisal methodology had not been updated to cope with modern combination therapies. “We simply cannot let research progress like this pass NHS patients by, and we urge for reform to the appraisal methodology to ensure new and effective combination therapies can be made available quickly at a price the NHS can afford.”
The UK still has one of the lowest breast cancer survival rates in western Europe, and this year about 11,5000 women will lose their lives to the condition.
Background: The cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor palbociclib, in combination with fulvestrant therapy, prolongs progression-free survival among patients with hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative advanced breast cancer. We report the results of a prespecified analysis of overall survival.
Methods: We randomly assigned patients with hormone-receptor–positive, HER2-negative advanced breast cancer who had progression or relapse during previous endocrine therapy to receive palbociclib plus fulvestrant or placebo plus fulvestrant. We analyzed overall survival; the effect of palbociclib according to the prespecified stratification factors of presence or absence of sensitivity to endocrine therapy, presence or absence of visceral metastatic disease, and menopausal status; the efficacy of subsequent therapies after disease progression; and safety.
Results: Among 521 patients who underwent randomization, the median overall survival was 34.9 months (95% confidence interval [CI], 28.8 to 40.0) in the palbociclib–fulvestrant group and 28.0 months (95% CI, 23.6 to 34.6) in the placebo–fulvestrant group (hazard ratio for death, 0.81; 95% CI, 0.64 to 1.03; P=0.09; absolute difference, 6.9 months). CDK4/6 inhibitor treatment after the completion of the trial regimen occurred in 16% of the patients in the placebo–fulvestrant group. Among 410 patients with sensitivity to previous endocrine therapy, the median overall survival was 39.7 months (95% CI, 34.8 to 45.7) in the palbociclib–fulvestrant group and 29.7 months (95% CI, 23.8 to 37.9) in the placebo–fulvestrant group (hazard ratio, 0.72; 95% CI, 0.55 to 0.94; absolute difference, 10.0 months). The median duration of subsequent therapy was similar in the two groups, and the median time to the receipt of chemotherapy was 17.6 months in the palbociclib–fulvestrant group, as compared with 8.8 months in the placebo–fulvestrant group (hazard ratio, 0.58; 95% CI, 0.47 to 0.73; P<0.001). No new safety signals were observed with 44.8 months of follow-up.
Conclusions: Among patients with hormone-receptor–positive, HER2-negative advanced breast cancer who had sensitivity to previous endocrine therapy, treatment with palbociclib–fulvestrant resulted in longer overall survival than treatment with placebo–fulvestrant. The differences in overall survival in the entire trial group were not significant.
Nicholas C Turner, Dennis J Slamon, Jungsil Ro, Igor Bondarenko, Seock-Ah Im, Norikazu Masuda, Marco Colleoni, Angela DeMichele, Sherene Loi, Sunil Verma, Hiroji Iwata, Nadia Harbeck, Sibylle Loibl, Fabrice André, Kathy Puyana Theall, Xin Huang, Carla Giorgetti, Cynthia Huang Bartlett, Massimo Cristofanilli