The market for breast cancer drug treatments in seven major markets will decline this year to a value of $9.3 billion, but will then rise to reach $10.6 billion in 2020, according to new forecasts.

By 2020, targeted agents produced by Roche, Genentech and Chugai will account for nearly half the market, adds the report, which is produced by Decision Resources and examines market prospects in the US, France, Germany, Italy, Spain, the UK and Japan.

Sales declines resulting from erosion for some key agents by generic and biosimilar competitors will be offset by an annual increase in the incidence of breast cancer in these markets, and by the launch and uptake of premium-priced emerging therapies, says the study.

In particular, it forecasts that generic erosion of Sanofi's Taxotere (docetaxel), Roche/Chugai's Xeloda (capecitabine) and Eli Lilly's Gemzar (gemcitabine), plus the aromatase inhibitors, will constrain market growth.

Breast cancer is one of the best-served oncology indications, but significant clinical and commercial opportunities exist for agents that can penetrate this lucrative market, the authors suggest.

"12 drugs are in Phase III development for breast cancer, a majority of which are targeted therapies," comments Decision Resources analyst Niamh Buckley. "We forecast that, through 2020, only three novel targeted therapies will gain approval for this indication - Novartis' (everolimus) and Roche/Genentech/Chugai's pertuzumab and trastuzumab-DM1 [T-DM1]," adds Dr Buckley.

The report forecasts that while Roche/Genentech/Chugai's Herceptin (trastuzumab) will lose patent protection in the world's major pharmaceutical markets over the next 10 years, the three firms' overall human epidermal growth factor (HER2)-positive breast cancer franchise will increase by more than $1 billion by 2020. 

Biosimilar erosion of perception is expected to minimal, initially, and to be offset by the companies' launch of two second-generation HER-targeted monoclonal antibody therapeutics - pertuzumab and T-DM1 - as well as a subcutaneous formation of Herceptin, says the report, which forecasts that, by 2020, Roche/Genentech/Chugai's HER2-targeted agents will account for nearly half the total market for breast cancer therapies.

The report also projects that the drug-treatable population for first-line therapy will decrease from 89,800 in 2010 to 87,000 in 2025.

"The decreasing trend in recurrence risk, in conjunction with early stage at diagnosis, will drive this decrease in first-line treatable populations," forecasts Decision Resources analyst Alison Isherwood. "HR+/HER2- patients will dominate the first-line therapy patient population, at 45%, followed by HER2+ (HR+ and HR-) patients at 31% and HR-/HER2- (triple negative) patients at 25%," says Dr Isherwood.