AstraZeneca said the United States Food and Drug Administration (FDA) granted an additional six month exclusivity period to market its breast cancer drug Arimidex (anastrozole), by granting paediatric exclusivity to the product.
The patent, extended to June 2010, had been scheduled to expire in December 2009.
Arimidex is currently approved in the US for postmenopausal women with various breast cancer related indications.
Dr John Patterson, executive director, Development, AstraZeneca said "Pre-clinical and clinical data supported the investigation of the therapeutic potential of Arimidex in paediatric conditions that manifest symptoms resulting from increased oestrogen production, for example: gynecomastia in pubertal boys and precocious puberty in girls with McCune-Albright Syndrome (MAS). While pleased to have been able to work with the FDA in investigating the potential benefits of Arimidex in these settings, AstraZeneca will not be seeking an indication in either of these paediatric conditions based on trial results."
AstraZeneca submitted a proposed paediatric study request to the United States Food and Drugs Administration (FDA) in 1999, in response to which the FDA issued a Written Request, which outlined four clinical studies to investigate the potential health benefits of Arimidex in two paediatric conditions: gynecomastia in pubertal boys and precocious puberty in girls with McCune-Albright Syndrome (MAS). The purpose of these studies was to examine the safety, efficacy and pharmacokinetics of Arimidex in these paediatric populations where an unmet need currently exists.
The Study 0006 (gynecomastia) did not show any evidence for an effect of Arimidex versus placebo in the treatment of moderate-to-severe pubertal gynecomastia; whereas Study 0046 (McCune Albright syndrome) suggested that Arimidex does not demonstrate a clear benefit in the treatment of precocious puberty in the heterogeneous population of girls with the rare disease of MAS. There was no observed benefit in terms of reducing the frequency of vaginal bleeding, decreasing the rate of increase in bone age or reducing growth rate in the overall group. Based on these results that AstraZeneca said it won't seek approval for the two paediatric indications.
In the US, Arimidex sales reached $507 million for the nine months of 2007. Arimidex has a market leading 38.3 percent share of total prescriptions for hormonal treatments for breast cancer. Sales for the nine months were up 15 percent, with total prescriptions 6 percent higher than last year.
AstraZeneca is a major international healthcare business engaged in the research, development, manufacture and marketing of prescription pharmaceuticals and the supply of healthcare services. It is one of the world's leading pharmaceutical companies with healthcare sales of $26.47 billion and leading positions in sales of gastrointestinal, cardiovascular, neuroscience, respiratory, oncology and infection products.