"We know the least about Aromasin because it is the newest of the three, " Osborne says.

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But Leung speculates that Aromasin might someday be part of a molecular cocktail--and that cocktail may include Celebrex.

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's aromatase inhibitor Aromasin, it improved survival without tumor growth to a median 7.4 months, compared with Aromasin alone.

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And Pharmacia (nyse: PHA - news - people ) has a similar but slightly different drug, Aromasin.

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Novartis studied Afinitor in a study of 724 patients who randomly received either Afinitor plus the breast cancer drug Aromasin or a placebo plus Aromasin.

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Aromasin is being tested against tamoxifen in clinical trials now.

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On Friday the drug was approved for use in combination with Aromasin for postmenopausal women with recurring HER2-negative breast cancer, after treatment with the drugs Femara and Arimidex.

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Leung is also excited about Aromasin, the so-called aromatase inactivator.

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Aside from Arimidex, there are two others: Aromasin, made by Pharmacia (nyse: PHA - news - people ), and Femera, made by Novartis (nyse: NVS - news - people ).

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