NPS Pharmaceuticals (NASDAQ: NPSP) is bringing its kids home. The biotech announced yesterday that it had reacquired the ex-North America rights to two drugs -- Revestive and Preotact -- that were licensed to Nycomed, which was subsequently acquired by Takeda Pharmaceutical.

Investors clearly liked the idea. Shares jumped 9.3% on the news. I'm not quite sure it's a good sign.

Preotact is approved in Europe for treating post-menopausal osteoporosis, but a majority of the value of the deal is for Revestive, which goes by Gattex in the states. Revestive was approved last year to treat an orphan disease called short bowel disease.

Takeda is letting go of the drugs for $50 million worth of NPS Pharmaceuticals stock up front. The biotech is also on the hook for another $30 million payment if the combined sales of the two drugs exceed $750 million in a calendar year.

That's pretty darn cheap. Back in 2007, Nycomed paid NPS $35 million up front just for the rights to Revestive. And the deal for the drug, which hadn't yet completed phase 3, included more than $150 million in additional milestone payments.

It could be that NPS is getting a great deal, but my guess is Takeda has looked at the potential market and realized it was too small to bother with. Presumably Takeda, with its larger presence outside North America, could market the drugs for cheaper than NPS will be able to do. Building out a commercial presence in Europe isn't going to be easy or cheap.

Regaining the rights to Revestive and Preotact makes NPS a more attractive takeover target. That might be the main driver for the increased valuation.

There's certainly precedence. Amylin Pharmaceuticals regained the rights to Byetta and Bydureon from Eli Lilly (LLY -1.81%) and was subsequently purchased by a joint venture of Bristol-Myers Squibb (BMY -0.27%) and AstraZeneca (AZN 0.49%). It's unlikely that Bristol-AstraZeneca would have made the purchase if Eli Lilly were still involved. It was a win-win-hopefully win. Eli Lilly was able to pursue other diabetes drugs and still get milestones and royalty payments, Amylin's investors saw shares nearly triple in value. It helped Bristol and AstraZeneca build out their diabetes franchise, although it's still to be determined whether the duo overpaid for the diabetes specialist.

I wouldn't buy NPS on the hopes of a quick buyout, though. Any potential buyers will likely want to see how Gattex/Revestive performs on the market before they make a bid. NPS will have to prove the doubters wrong -- Takeda included -- before it'll get bought out.