The US Food and Drug Administration (FDA) has approved Novartis' Afinitor as a treatment for postmenopausal women with advanced hormone receptor-positive, HER2-negative breast cancer.
Afinitor (everolimus) has been given a green light for use alongside Pfizer's Aromasin (exemestane) in advanced breast cancer patients who have already failed treatment with aromatase inhibitors, namely Novartis' Femara (letrozole) or AstraZeneca's Arimidex (anastrozole).
Novartis said the go-ahead marks "the first major advance for US patients with advanced hormone receptor-positive breast cancer since aromatase inhibitors were introduced more than 15 years ago".
It is also the first approval of an mTOR inhibitor in the treatment of advanced hormone receptor-positive breast cancer in the US, added the firm. Afinitor has also been recommended for approval in this indication by the European Medicine Agency's Committee for Medicinal Products for Human Use (CHMP).
The approval was based on the results of the BOLERO-2 trial, which found that treatment with Afinitor plus Aromasin more than doubled median progression-free survival (PFS) to 7.8 months, compared to 3.2 months with Aromasin alone.
Endocrine therapy is likely to remain the cornerstone of treatment for hormone receptor-positive breast cancer, but most women develop resistance to these therapies, according to Novartis.
"Afinitor is the first and only treatment that boosts the effectiveness of endocrine therapy, significantly extending the time women with advanced breast cancer live without tumour progression," commented Gabriel Hortobagyi of MD Anderson Cancer Centre in the US.
"This approval redefines the treatment and management of advanced hormone receptor-positive breast cancer, offering a critical new option for physicians and patients."
Afinitor is already approved to treat four other types of malignant and non-malignant tumour, including advanced renal cell carcinoma; neuroendocrine tumours of pancreatic origin; renal angiomyolipoma and tuberous sclerosis complex (TSC); and subependymal giant cell astrocytoma associated with TSC.
These indications brought in $318m in sales in the first six months of 2012, but breast cancer could take the product to another level commercially, adding another $1bn a year in potential peak sales, according to analysts.
Meanwhile, Novartis is also developing Afinitor for gastric cancer, HER2-positive breast cancer, hepatocellular carcinoma and lymphoma, and expects to file marketing applications in these indications from 2012 onwards.