The Motley Fool Rule Breakers growth investing service has been making buy and sell recommendations for members since 2004. Now it's time for those members to help shape the service, through the "Take That!" contest currently under way. Readers nominated the companies they thought were no longer Rule Breakers and that should be sold from the scorecard, and the five best bear cases are now up for a vote. The winning (losing!) stock will be revealed in the next issue of Rule Breakers -- and quite possibly a sell recommendation to go along with it!

In June 2005, Fool biotech analyst Charly Travers recommended Encysive Pharmaceuticals (NASDAQ:ENCY) to Rule Breakers subscribers. In the past 15 months, the stock has lost more than half its value (51%), while the S&P 500 has gained 14%.

So is it time to cut the line and move on, or is Encysive still poised for long-term outperformance?

We're bullish
First, some background. Encysive is a biotechnology company that develops and markets new drugs. It has a licensing deal with GlaxoSmithKline (NYSE:GSK) that provides royalty payments for Argatroban, a medication used to treat heparin-induced thrombocytopenia. Encysive's golden goose, Thelin, which treats pulmonary artery hypertension (PAH), remains under review by the FDA.

In his buy recommendation, Charly believed Thelin was a best-in-class drug for treating PAH, a disease affecting more than 100,000 people worldwide. He believed Thelin could launch within a year (it has been approved in Europe and is awaiting approval in the United States) -- which would be huge, because Encysive owns worldwide rights to the drug and would receive all its profits.

However, Charly believed Encysive was not a traditional Rule Breaking company. "It hasn't developed a fancy new technology that will dominate all of the drug industry, and its lead drug is not even the first mover in its space."

Nevertheless, with Thelin, Encysive "built a better mousetrap." The drug offers competitive advantages over Actelion's Tracleer, Glaxo's Flolan, and Remodulin from United Therapeutics (NASDAQ:UTHR). These latter two drugs must be administered continuously with an infusion pump, a huge inconvenience for patients.

And while Charly acknowledged that there were no assurances the FDA would approve Thelin -- in 2006 or ever -- the potential rewards are huge from the stock's current price.

No, we're bearish!
In the "Take That!" contest, FoolishMage laid out the Encysive bear case. While he acknowledges that Encysive could become a player in the PAH space, he thinks Thelin's delays have changed the story of this stock. "With rival companies like Myogen (NASDAQ:MYOG) and Pfizer (NYSE:PFE) offering competing drugs, the time-to-market advantage is no more," he wrote.

Time, in short, is no longer on Encysive's side. Furthermore, he believes that the medical community is getting comfortable with Tracleer as the means to treat PAH. That drug's sales are booming -- so why switch to Thelin?

FoolishMage believes Encysive has the "potential for a lot of growth." It's just that the investment thesis -- the FDA approval of Thelin and subsequent sales boost -- have "materially affected" the potential for growth. In sum, he believes the risk-reward scenario no longer justifies Encysive's status as a Rule Breaker.

So which one is it?
Community sentiment is largely bullish. According to Motley Fool CAPS data, Encysive is a four-star stock (out of five possible stars); 324 CAPS players have rated it an "outperform," while only 12 have rated it "underperform" vs. the S&P 500. CAPS players feel that Thelin will get its long-awaited FDA approval, and that Encysive will then take off. The analysts consensus is neutral. According to Thomson data, Encysive has a mean recommendation of 2.4 on a 1-to-5 buy-to-sell scale.

So ... which one is it? For the full bull and bear Encysive arguments, and to read the cases against each of the five finalists, click on over to Rule Breakers Central. If you're not a member, you can access the service, read all of our recommendations, and cast a vote in our contest -- all with a completely free, no-strings-attached 30-day trial.

For more coverage: It Might Be Time to Pare Back

Brian Richards owns no stocks mentioned in this article. Pfizer is an Inside Value pick. GlaxoSmithKline is an Income Investor recommendation. The Fool has a disclosure policy.