AstraZeneca is discontinuing US sales of its cancer drug Nolvadex (tamoxifen) from June, after mounting competition from generic products has substantially eroded sales of the brand.

A spokeswoman for AstraZeneca told PharmaTimes World News that the decision was made on “dwindling demand for the product, annual US sales of which have dropped to just a few million dollars.”

Nolvadex pulled in global sales of just $114 million last year, down from $134 million in 2004, but “AstraZeneca has no plans to discontinue manufacture of tamoxifen in the UK, which supplies the rest of the world.”

She went on to say that, given the growing popularity of generic tamoxifen, “discontinuation of Nolvadex in the US will in no way restrict patient access to the drug,” which for many years was considered the gold standard of cancer treatment.

Industry observers already believe that tamoxifen's crown will be stolen by the likes of AstraZeneca’s newer cancer drug, the aromatase inhibitor Arimidex (anastrazole), as well as Novartis' Femara (letrozole) and Pfizer's Aromasin (exemestane).

Data published at the end of 2004 showed that five years of treatment with Arimidex was more effective than the standard five-year tamoxifen therapy in terms of survival, and that the agent cut the relative risk of breast cancer recurrence by 17% over Nolvadex.