medwireNews: Advanced breast cancer patients who have failed prior endocrine treatment may receive a progression-free survival (PFS) benefit if palbociclib is added to fulvestrant, a phase III trial indicates.
The advantage accorded by the small-molecule inhibitor of CDK4 and CDK6 was irrespective of the menopausal status of the women, the team reports in The New England Journal of Medicine.
The research was concurrently presented at the annual meeting of the American Society of Clinical Oncology, held in Chicago, Illinois, USA.
The double-blind PALOMA3 trial comprised women with advanced breast cancer positive for oestrogen and/or progesterone hormone receptors but negative for epidermal growth factor receptor 2 who had progressed or relapsed during endocrine therapy.
After a median follow-up of 5.6 months, the risk of progression or death was a significant 58% lower in the 347 women randomly assigned to receive palbociclib plus fulvestrant than in the 174 participants given placebo and fulvestrant, with a median PFS of 9.2 versus 3.8 months.
And the results continued to favour palbociclib when women were stratified according to their menopausal status – with comparable hazard ratios of 0.44 and 0.41 in pre- and perimenopausal women versus postmenopausal women.
Moreover, global quality of life, as assessed by the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Core Module, was “generally maintained” in palbociclib-treated patients, but “deteriorated significantly” in those given placebo (mean change from baseline of –0.9 vs –4.0 points), say the researchers.
Neutropenia and leukopenia were the most frequent grade 3 or 4 adverse events in the palbociclib group, occurring in 62.0% and 25.2% of patients, respectively – this compared with an incidence of 0.6% for either toxicity in the placebo group.
The team led by Nicholas Turner (Royal Marsden Hospital and Institute of Cancer Research, London, UK) notes, however, that the occurrence of febrile neutropenia was low in both treatment arms, observed in 0.6% of patients given palbociclib and 0.6% of those given placebo.
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