Last December, Orexigen (NASDAQ:OREX) received a positive opinion from the Committee for Medicinal Products For Human Use, or CHMP, on the application to market its obesity drug Mysimba in the EU.

That's essentially an approval in the EU, although it requires a rubber-stamp from the European Commission, signing off on the decision from CHMP. Orexigen received the European Commission decision in March after a slight delay that turned out to be a non-issue.

Now, nearly six months later, Mysimba still hasn't been launched in the EU. By comparison, it took about a month from FDA approval to launch in the U.S. where the drug goes by the name Contrave.

The difference in timing is because Orexigen already had a marketing partner, Takeda, set up in the U.S. but went into the EU decision without one.

That wasn't necessarily a bad idea as the biotech can obviously get better deal terms if potential partners aren't worried about whether the drug will be approved. That logic doubled after both Arena Pharmaceuticals (NASDAQ:ARNA) and VIVUS (NASDAQ:VVUS) failed to gain approval in the EU.

Show me the partner
Six months isn't an excruciatingly long time to ink a deal, but Orexigen's management said they felt confident that Mysimba would be approved ahead of the CHMP decision. "We're confident of positive opinion," Michael Narachi, Orexigen's president and CEO said at the Credit Suisse Healthcare Conference last November. With that kind of high expectations, it seems like Orexigen would have been talking to potential partners before the CHMP decision, shortening the time it took to finalize a deal after the approval.

While it's entirely possible that Orexigen is having trouble finding a marketing partner, it seems more likely that its squabble with U.S. partner Takeda earlier this year caused talks to slow down.

Orexigen found itself in a messy situation when it wanted to patent the potential for Contrave/Mysimba to lower the incidence of cardiovascular risk, but was still running a trial that the data to support the patent came from. As it turns out, the company told too many people about the great data, which led to the FDA saying the trial wouldn't be able to count toward Orexigen and Takeda's requirement to run a post-marketing study to show that Contrave wasn't causing cardiovascular problems (the companies didn't have to show a cardiovascular improvement; that was just a side benefit).

But since Takeda has to pay for part of the safety study, the Japanese pharma was understandably a little miffed about the consequences of Orexigen's actions. The companies eventually settled their dispute with Orexigen agreeing to pay for the new cardiovascular outcomes trial, up to the estimated $210 million total cost of the study with the companies sharing equally any costs that exceed expectations.

The dispute probably rules out Takeda as a potential global partner, especially since, as part of the reworked deal, Takeda gave back rights to Canada and Mexico. But wrapping up the fight with Takeda will be beneficial for Orexigen in the long run. It's certainly understandable how other potential partners might want to wait for the fight to be resolved before signing on the dotted line.

Why Europe is so important
Even though it launched third, Contrave has done pretty well in the U.S., taking market share from Arena Pharmaceuticals' Belviq and VIVUS' Qsymia. According to IMS prescription data sent out by RBC Capital Markets analyst Simos Simeonidis last month, Contrave was the most prescribed obesity drug with 37.2% of the prescriptions. Belviq had 30.5%, Qsymia had 27.9% and Novo Nordisk's Saxenda brought up the rear with just 4.3%.

But in Europe Orexigen won't have to worry about Arena Pharmaceuticals or VIVUS since both companies haven't been able to convince EU regulators that their drugs' benefits outweigh the potential risks. With the lack of major competition -- including a generic drug phentermine that's also available in the U.S. but not the EU -- Mysimba has a lot of potential in Europe.

If it can just find a partner to market the drug.

Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Novo Nordisk. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.