Anglo-Swedish drugmaker AstraZeneca’s Arimidex (anastrazole) has been granted full clearance by the US Food and Drug Adminstration as an adjuvant therapy of early-stage breast cancer in postmenopausal women.

In September 2002 the FDA cleared a supplemental New Drug Application for the already-marketed anticancer agent under its accelerated approval process [[06/09/02/b]], which is given to a drug that has yet to show a clinical benefit but indicates a patient benefit in an at-risk population. Accelerated approval was based on strong results from the ATAC (Arimidex Tamoxifen Alone or in Combination) trial, one of the world’s largest breast cancer treatment studies, which remains one of the longest running studies investigating treatment after surgery for early breast cancer.

Complete five-year data from the ATAC trial, as requested by the FDA for full marketing approval, was unveiled in December 2004 [[09/12/04/b]], and showed that Arimidex significantly cut the relative risk of breast cancer recurrence by 17% over Nolvadex (tamoxifen), the previous gold standard of treatment.

According to the firm, the drug is the only aromatase inhibitor with study results touting full five years of efficacy and safety in the primary adjuvant setting. Moreover, it now represents the only agent in its class with proven superior efficacy in disease-free survival to tamoxifen, which should help the firm capture the controlling slice of this highly lucrative market. Sales of Arimidex in the second quarter alone jumped 50% over the comparable quarter last year to edge over the $1 billion-dollar mark [[29/07/05/d]].