Big Pharma has been shedding all sorts of assets in recent years - human as well as intellectual property.

While that poses big risks for an area like Philadelphia that is home to so many large pharmaceutical companies, it can be an opportunity for new company formation.

An announcement last week involving brand-name GlaxoSmithKline P.L.C. and no-name AltheRx Inc. shows how.

Backed by a single, unidentified private investor, AltheRx acquired solabegron, a compound that GlaxoSmithKline had been studying as a treatment for overactive bladder in women and irritable-bowel syndrome. However, after taking the compound through Phase II clinical studies, GlaxoSmithKline halted work on it.

AltheRx chief executive officer Shawn O'Brien said it had taken his three-person firm about a year to complete the deal. "There are tons of assets in Big Pharma that are not getting moved around these days," he said.

O'Brien declined to disclose how much cash AltheRx paid to acquire solabegron. But he had a simple explanation for how his small Chadds Ford company came to identify this compound from among the hundreds that big drug companies have given up on over the years: He had some great firsthand information.

Eliot Ohlstein, who is now AltheRx's chief scientific officer, had been the senior vice president of the Urology and Cardiovascular Center of Excellence for Drug Discovery at GlaxoSmithKline in Upper Merion. Ohlstein left in April 2008 to spin off some other Glaxo technology into a company called Venuvics Pharmaceuticals.

AltheRx will pursue Phase III clinical studies of solabegron for overactive bladder later this year. It's a condition characterized by the sudden urge to urinate and having to go more than eight to 10 times a day. The companies that sell prescription drugs to treat what they call OAB say it affects more than 35 million Americans.

Decision Resources Inc., a Burlington, Mass., market-research firm, projects the OAB market will grow from about $3 billion in 2009 to nearly $4 billion in 2019 in the United States, Japan, and five European countries.

It's a market currently dominated by the Detrol franchise, sold by Pfizer Inc., and Vesicare, which is jointly marketed by Japan's Astellas Pharma Inc. and GlaxoSmithKline. Pfizer's 2010 sales from Detrol and Detrol LA totaled $1.01 billion globally. Sales of Vesicare totaled 82.3 billion yen for Astellas in fiscal 2009, or about $1 billion.

Consider that Pfizer also sells Toviaz, Warner Chilcott P.L.C. markets Enablex, and Endo Pharmaceuticals Holdings Inc. has Sanctura, and O'Brien admits that AltheRx is trying to join a crowded market.

However, he said all of those therapies belonged to a different class of drugs known as antimuscarinics, which have side effects including dry mouth, constipation, blurred vision, and dizziness. Solabegron belongs to a different class, and studies so far have turned up fewer side effects, he said.

Plans call for AltheRx (O'Brien combined the Rx symbol common in the pharmaceutical business with the name "Althea," which comes from Greek mythology and means "healing") to recruit for late-stage Phase III clinical studies late this year, O'Brien said.

That will put AltheRx months behind Astellas, which has already completed its Phase III studies of a similar-acting OAB drug called mirabegron. Astellas announced the first results of those studies last week at the European Association of Urology congress in Vienna.

Plus, Astellas submitted documentation last summer to the Pharmaceuticals and Medical Devices Agency in Japan seeking market authorization. It could do the same with the Food and Drug Administration this summer.

In addition, a start-up company in the United Kingdom called Provesica Ltd. is also working on a non-antimuscarinic drug. It raised 4 million British pounds, or about $6.4 million, from venture investors, in December to spin out that technology from Xention Ltd., another British company.

What O'Brien can control is turning what is now a virtual company into an operating company with 13 employees by the end of the year. O'Brien, an 18-year veteran of AstraZeneca P.L.C., has most recently been leading small drug developers, including Profectus Biosciences Inc., of Baltimore, and before that Solstice Neurosciences Inc., of Malvern.

Having worked in California, Maryland, England, and Canada, O'Brien is glad to be building AltheRx in the Philadelphia region, which he said was richer in resources to nurture a life-sciences firm with the urge to grow.