Switzerland-based Novartis has announced encouraging results from a pivotal Phase III trial demonstrating the efficacy of Afinitor (everolimus) tablets in significantly delaying tumour growth in HER2-positive advanced breast cancer.
The study met the primary endpoint of progression-free survival (PFS) by demonstrating 22% reduction in the risk of disease progression with the addition of everolimus, an mTOR inhibitor, to trastuzumab and vinorelbine in heavily pretreated patients.
Emory University School of Medicine department of haematology and medical oncology educational affairs professor and vice-chair and lead study author Ruth O'Regan said the data demonstrates everolimus' impact in heavily pretreated HER2 positive advanced breast cancer patients.
"Everolimus works differently than available treatment options for HER2 positive advanced breast cancer by inhibiting mTOR, and may offer an important new option for physicians and their patients," O'Regan said.
Median time to progression in the everolimus combination arm of the breast cancer trials of oral everolimus-3 (BOLERO-3) study was 7.0 months compared to 5.8 months in the placebo combination arm.
About 27% of patient population was pretreated with a lapatinib-containing regimen, while all the subjects showed resistance to trastuzumab-containing regimens.
The overall survival findings, the trial's main secondary endpoint, have not been matured yet, however no new adverse events were noted in the trial.
Neutropenia, stomatitis, anaemia, leukopenia, fatigue, pyrexia, diarrhoea, nausea, decreased appetite and constipation are the most common all-grade adverse reactions, while the most common Grade 3-4 adverse reactions included neutropenia, leukopenia, anaemia, stomatitis, fatigue, febrile neutropenia, diarrhoea, pyrexia, nausea, hyperglycemia and thrombocytopenia.
Novartis Oncology, oncology development and medical affairs global head Alessandro Riva said; "Our previous advanced breast cancer studies have proven that everolimus plays a key role in treating women with hormone-receptor positive, HER2 negative advanced breast cancer, and now we know it may have a substantial impact in HER2 positive advanced breast cancer."
Image: Excised human breast tissue, showing a stellate area of cancer 2cm in diameter. Photo: John Hayman.