The reemergence of obesity drugs after more than a decade has earned ardent investor attention. VIVUS (VVUS) and Arena Pharmaceuticals (ARNA) led the pack and spent most of the year in an approval do-si-do. VIVUS' Qsymia became the first drug to the market, but its lukewarm initial performance cooled market confidence. With its pivotal year drawn to an end, and Arena's Belviq coming fast around the corner, can VIVUS win for losing?

Advancing toward approval
VIVUS had plenty of reasons to celebrate in the early months of the year. A Food and Drug Administration advisory panel recommendation in February sent shares up more than 90%. The company's erectile dysfunction medication Stendra earned FDA approval in late April. But Stendra's good news was slightly preceded by the first of Qsymia's many snags.

Qsymia originally ran ahead of Arena's Belviq in the approval process and would've become the first drug both approved and to market. But the drug's April decision was delayed three months due to a late regulatory filing concerning Qsymia's risks. That delay allowed Belviq to become approved drug in June while Qsymia's came in July.

Belviq's earlier approval essentially didn't matter since it had to continue into DEA scheduling, a months-long process that determines a drug's controlled substance class. Qsymia could skip that part because it's made of two previously existing drugs: phentermine and the active ingredient in Topamax.

What did matter? The risk warnings that had delayed Qsymia in the first place.

REMS setback
The FDA made VIVUS file a risk evaluation and mitigation strategy, or REMS, for Qysmia. The specifics mean that doctors must warn women patients about possible birth defects associated with taking the drug while pregnant. Women should take a pregnancy test before starting the medication and then once every month while on the regimen. The REMS also restricted Qsymia's sales to mail-order pharmacies.

That location restriction, added to VIVUS' lack of big pharma partner for marketing, was an early warning of low initial prescription rates. And it looked to strengthen Arena's position since Belviq didn't require a REMS -- though it did get slapped with a post-market set of safety trials but those won't affect its launch.

But Qsymia still made it to market first and had a wide open field in which it could power-walk out of the gates.

Launch to turning point
Qsymia's much-awaited launch came quietly in a regulatory filing, whereas the company issued a press release about a likely European denial for the drug. The flow of patients toward Qsymia was almost as quiet. Thirty percent of the prescriptions never left the pharmacy.

The reticence largely stemmed from insurance companies not wanting to cover what some may consider an optional drug. Aetna (AET) finally came around and offered coverage, sending VIVUS shares up more than 10%. Express Scripts (ESRX) soon followed suit. VIVUS also implemented a 14-day free trial program to attract patients to give the drug a chance.

Something's working because prescription rates have risen recently, according to two different research firms. The amount of the increase varies widely, but any increase is a good thing at this point. But will this hold off competition that's just around the corner?

The coming competitors
Belviq will hit the market in 2013. Qsymia proved more effective in trials, but Belviq's lack of REMS restrictions may attract more women patients, despite the fact the drug is also contraindicated for pregnant women. Arena's drug could also stand alone in the European market if it wins approval. Arena benefits from having Eisai as a partner, whereas Vivus flies alone.

Orexigen (NASDAQ: OREX) lags further behind with its obesity meds but still earns mention with the front runners. The FDA forced its drug Contrave to circle back for cardiovascular safety trials. But it's moving through those paces swiftly and could be to the market within the next couple of years.

Being first to market won't matter in the long-run for these drugs because of the prescribing directions. Patients will take one medication  and, if a certain percentage of weight loss isn't met, stop that regimen. Another drug could prove more effective, making use of these drugs a highly personalized experience.

Foolish final thoughts
VIVUS got off to a shaky start, and time grows short before the competition arrives. It will take at least another year before investors have any real idea of which drug patients will lean toward. This was VIVUS' year, but Arena will dominate the news in 2013.