Where investors see a specialty pharma trying to get back on track -- and not worth all that much -- Merck (NYSE: MRK) sees an opportunity to add on some products on the cheap.

The big pharma is buying Inspire Pharmaceuticals (Nasdaq: ISPH) for $5 per share, a 26% increase over the previous day's close. The deal values Inspire at $430 million.

Inspire was worth a heck of a lot more just a few months ago before its cystic fibrosis drug, denufosol, failed a key phase 3 trial. While certainly disappointing, a sale was the best solution for investors. Competing with Novartis (NYSE: NVS), which bought Alcon (NYSE: ACL), Bausch & Lomb, and Allergan (NYSE: AGN) wasn't going to be easy.

Despite getting revenue from three different drugs, Inspire isn't profitable. Still, looking at the revenue coming in, the deal looks pretty good. The takeout price is about four times Inspire's revenue last year, which is pretty cheap considering that nearly half of the revenue comes in the form of royalties from Allergan's dry-eye treatment Restasis. Most of the royalties should head straight down to Merck's earnings line.

Merck will be able to cut overhead -- no extra CEO to pay -- plus the company inherits a sales force that can sell its glaucoma treatment, Saflutan, which is currently under review at the Food and Drug Administration.

In addition to the currently approved drugs, Inspire has a couple of pipeline drugs, and Inspire has done the hard work cutting its pulmonary programs to focus on eye care a few months ago. Inspire could see the writing on the walls; the pulmonary pipeline wasn't going to pump out the drug candidates.

This isn't s a life-changing event like Merck's $41 billion purchase of Schering-Plough, but if Merck could do 100 more of these deals, I'd bet they'd collectively produce a lot more than Schering ever will.

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