There are two ways for a new drug to gain market share: be better than the competition or be easier for patients to use. Bristol-Myers Squibb (NYSE:BMY) and Pfizer (NYSE:PFE) appear to be doing the latter with their new anticoagulant apixaban.

Phase 2 study results presented at a conference last weekend show that apixaban had failure rates equal to those of the standard treatment, which involves an injectable anticoagulant plus a drug containing warfarin. Failure involved a reoccurence of deep vein thrombosis (DVT). So the drug isn't showing that it will perform better, but it should have a distinct advantage over its competitors since apixaban is taken orally.

The drug also has the potential to boost the fortunes of Bristol-Myers and Pfizer if it does well in phase 3 trials looking at its effectiveness in preventing strokes. The phase 2 study focused on its blood-thinning abilities.

Drugs such as Sanofi-Aventis' (NYSE:SNY) Lovenox that are used to prevent blood clotting must be injected. And warfarin is notoriously hard to regulate because it interacts with food and other medications. Warfarin is marketed by Bristol under the brand name Coumadin, so approval of apixaban might shift some sales from one column of Bristol's ledger to another. But since warfarin isn't under patent protection, Bristol should see a net increase in prescriptions if apixaban is approved.

There were no adverse effects of apixaban -- most importantly, no liver damage was seen. In 2004, AstraZeneca's (NYSE:AZN) anticoagulant Exanta was turned down by the FDA due to increased liver toxicity.

Apixaban has already moved into separate phase 3 clinical trials testing its ability to prevent strokes in patients with atrial fibrillation and its ability to prevent blood clots in patients with venous thromboembolism (VTE), which includes DVT and pulmonary embolisms. The trials should wrap up in 2009 and the companies are on target to file for marketing approval in the second half of 2009.

Bristol developed apixaban in-house and partnered it with Pfizer earlier this year. Bristol has already received a $250 million payment for the deal and could get an additional $750 million as milestones are met. The two companies will split the profits/losses equally on a global basis. Given Pfizer's experience with developing cardiovascular drugs, the move seems like a good one for Bristol-Myers.

The main competition for apixaban will likely come from Bayer (NYSE:BAY) and Johnson & Johnson (NYSE:JNJ) which have a new oral anticoagulant, Xarelto, that has recently completed phase 3 trials. If it gains FDA approval, it would have a one-year head start on apixaban in treating VTE.

However, since the use of anticoagulants for preventing strokes is a chronic therapy, the market for that indication is much larger than for the treatment of VTE. In that race, Bristol-Myers may have the slight edge since Xarelto probably won't gain market approval for preventing strokes until 2010. The race is certainly heating up, but until there's a head-to-head clinical trial, it will be difficult for investors to determine which drug will get the lion's share of the market.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any companies mentioned in this article. The Fool has a disclosure policy.