Avodart/Jalyn (dutasteride, dutasteride/tamsulosin)
Company: GlaxoSmithKline
Disease: Benign prostatic hypertrophy
Global 2013 sales: $1.34 billion (£857 million)
Patent expiration date: November 2015

Avodart and its combination-pill cousin Jalyn haven't been top sellers for GlaxoSmithKline ($GSK), though they have been solid performers. As treatments for enlarged prostate and its complications, such as prostate-driven urinary problems, they're not the sort of meds to pump out big sales on price, as rare disease or cancer drugs can. Nor are they remedies for life-threatening, common maladies like diabetes or heart disease.

Glaxo meant to change all that, with a bid to win FDA approval for Avodart as a tool to prevent prostate cancer. Some early trials suggested that Avodart patients did have a lower risk of developing the disease. And it would have been a big market; the new use could have added up to $1 billion to annual sales, analysts estimate.

But a small minority of men experienced the opposite effect while taking the pills, according to the FDA. Rather than winning a cancer-prevention indication as hoped in 2011, Avodart got a warning saying that it could help fuel growth of high-risk prostate tumors.

Without the hoped-for boost in cancer prevention--and despite competition from Merck's ($MRK) Proscar and Propecia--Avodart has continued to deliver hundreds of millions in sales annually and blockbuster-level revenue in recent years. Obviously, Glaxo was in no hurry to lose patent protection for the med. The company successfully fought off a patent challenge by Watson Laboratories (now Actavis ($ACT)) and its fellow generics maker Barr Pharmaceuticals, winning backing from a federal judge for its patent that expires in November 2015.

Meanwhile, Glaxo has managed to grow Avodart's sales rather impressively in emerging markets. By cutting prices in developing countries, the company pumped up volumes to the point where Avodart's emerging markets sales grew 76%.

For more:
Merck's Propecia and Proscar linked to sexual dysfunction
Watson seeks to market generic Avodart
FDA denies cancer-prevention use for GlaxoSmithKline's Avodart

-- Tracy Staton (email | Twitter)