Trading of biopharmaceutical company Theravance (NASDAQ: THRX) was halted on Tuesday. A major decision hung in the balance as the U.S. Food and Drug Administration's Pulmonary-Allergy Drugs Advisory Committee, or PADAC, reviewed umeclidinium/vilanterol, which Theravance hopes to market under the name Anoro Ellipta.

Shortly before 4 p.m. ET, the decision was announced. Here's what you need to know.

Solid support
PADAC voted three times on Anoro -- and the drug developed by Theravance and partner GlaxoSmithKline (NYSE:GSK) won convincingly every time. The committee voted 11-2 in support of recommending the drug for approval by the FDA as a treatment for patients with chronic obstructive pulmonary disease, or COPD.

Anoro gained unanimous approval on efficacy. That's not surprising. Theravance and Glaxo announced very positive results in July 2012 from four phase 3 studies of the drug. Anoro was found to be more effective than the current leading COPD drug, Spiriva, which is marketed by Pfizer (NYSE:PFE) and Boehringer Ingelheim.

There was a little dissension on the question of safety, but support was still solid. PADAC voted 10-3 that the safety of Anoro had been adequately demonstrated. The most common adverse events from the clinical studies were headache, nasopharyngitis, upper respiratory tract infection, cough, oropharyngeal pain and back pain. However, the three committee members voting negatively on safety could have been more concerned about some of the cardiovascular adverse events that occurred in patients participating in the studies.

Looking ahead
This committee recommendation doesn't bind the FDA to approval for Anoro. The margin of the vote bodes well for success, though. The FDA's decision date is scheduled for Dec. 18. I expect that Theravance and Glaxo will get more good news then.

Anoro Ellipta could be a game changer in the world of COPD. While Spiriva and Glaxo's Advair dominate now, Anoro seems poised to take market share away quickly once approved. Spiriva is a long-acting muscarinic antagonist, or LAMA. Advair is a long-acting beta agonist, or LABA. Anoro, assuming it gains approval, will be the first combination LABA/LAMA drug on the market.

Theravance and Glaxo might not enjoy the solo position for too long, though. Novartis (NYSE:NVS) also has a LABA/LAMA combo drug on the way. The company already submitted QVA149 for regulatory approval in Europe and Japan. However, dosing issues resulted in a delay in filing in the United States. Novartis expects to submit a New Drug Application, or NDA, for its new COPD drug in 2014.

Even with the prospects of having another similar drug enter the market, analysts project that Anoro could reach peak annual sales of $1.4 billion. While Theravance won PADAC's vote on Tuesday, it will keep a higher percentage of Anoro's revenue thanks to a negative vote by Elan (NYSE:ELN) shareholders.

In May, Theravance and Elan entered into an agreement where Elan would pay $1 billion upfront for a 21% stake in royalties for four drug programs, including Anoro Ellipta. However, Elan shareholders voted down the agreement in June.

Theravance shares jumped around 4% in early after-hours trading. The stock could easily go higher from here, but keep in mind that the FDA panel's decision wasn't a surprise. With a market cap more than $4 billion on relatively low current revenue, ultimate approval of Anoro is already largely baked into the price. That being said, even expected good news can still do wonders for smaller pharmaceutical stocks.