IVAX gets US go-ahead for generic Nolvadex

IVAX Corp has been granted final approval in the USA for a genericversion of AstraZeneca's breast cancer drug Nolvadex (tamoxifen citrate) in 10mg and 20mg tablet formulations. The approval marks the start of true competition in the market for the widely-used anti-estrogen; aside from Nolvadex, a generic version has been sold under license by Barr Laboratories since 2001, when AstraZeneca and Barr settled in a patent litigation suit (Marketletters passim).

IVAX' approval was followed swiftly by similar clearances for tamoxifen products from Mylan Laboratories, Teva Pharmaceuticals, Barr and Andrx Pharmaceuticals. Combined sales of Nolvadex and Barr's licensed generic reached around $500 million last year. The approvals were made possible by the expiry of AstraZeneca's pediatric exclusivity for Nolvadex on February 20.

The impact of the new generics is likely to be felt more fiercely by Barr than AstraZeneca, as the latter has seen the importance of Nolvadex wane in recent years as other drugs, and notably the follow-up breast cancer agent Arimidex (anastrozole), have gained ground. In 2002, sales of Nolvadex were $480 million worldwide, a decline of 22% on 2001, and down 27% to $337 million in the USA alone. And Barr is already experiencing problems with tamoxifen; sales of the drug by the firm declined $100 million to approximately $37 million in the second quarter of fiscal 2003, its most recent set of results, due to the depletion of its distributed tamoxifen inventory.