The Novartis healthcare group in Basel says the European Union has approved its Femara drug for the treatment of advanced breast cancer in post-menopausal women.
Femara also received approval from Britain's Medicine Control Agency for first-line breast cancer treatment under a separate national procedure, the group said.
A Novartis statement on Friday said that approval of the treatment was based on a study which showed that Femara delayed the progression of advanced breast cancer for 9.4 months, compared to six months for tamoxifen, the standard therapy.
"This is exciting news for the thousands of post-menopausal women with advanced breast cancer because Femara presents a more effective option than the gold standard tamoxifen in treating their disease," said Dr Henning Mouridsen, a professor at Copenhagen University Hospital and lead investigator for the drug trial.
The study also showed favourable differences on overall tumour response rates, clinical benefits, and time to treatment failure.
Novartis said adverse reactions to Femara were generally mild to moderate, the most commonly reported being bone pain, hot flushes, back pain, nausea and arthralgia.
Earlier this month, Femara received approval from the United States Food and Drug Administration.
swissinfo with agencies