BOSTON ( TheStreet) -- The Biotech Stock Mailbag is open for business. @scramjet asks, "How do you feel about $CPRX?" Ambivalent. The upcoming phase IIb study of CPP-109 (vigabatrin) in cocaine addiction is an important catalyst for Catalyst Pharmaceutical Partners ( CPRX) but guessing the outcome is challenging. Results from the study, even if positive, may be hard to interpret. I haven't noticed traders glomming onto Catalyst yet as a "run-up" trade into the vigabatrin study results expected between now and November 15. Catalyst has been trading flat in the $1.50-to-$1.60 range since the beginning of the month. The big move in the stock from 50 cents to $1.40 occurred in July after Catalyst set the CPP-109 study results for September -- earlier than expected. When September came and went with no results, Catalyst pushed the date back to the first half of November. Vigabatrin has been approved for decades as an epilepsy/seizure medicine. The drug works by blocking an enzyme responsible for the breakdown of the neurotransmitter GABA in the brain. This increases GABA levels. In addiction, increased GABA levels dampen the effect of dopamine, the neurotransmitter responsible for the "pleasure and reward" perceptions that comes when someone snorts cocaine. GABA also induces relaxation and sleep, which may reduce addictive cravings. CPP-109 is Catalyst's formulation of vigabatrin. The phase IIb study enrolled 200 patients undergoing treatment for cocaine addiction. After a short pre-treatment screening period, patients are randomized to receive CPP-109 or placebo in addition to addiction counseling for nine weeks. The primary endpoint of the study is the proportion of patients in each treatment group who are cocaine abstinent during the last two weeks of treatment. Secondary endpoints include the number of days in which cocaine was used and clean urine screens (both measured during the nine-week treatment phase). Patients are also being followed for another 15 weeks after treatment with CPP-109 or placebo ends. During this followup period, the study will measure the percentage of patients in each arm who relapse. This is the second phase II study of CPP-109 in cocaine addiction that Catalyst has conducted. The first study was disastrous: 186 patients were enrolled but only 67% completed the 12 weeks of treatment with either CPP-109 or a placebo. Forty-eight percent of patients completed the full 24 weeks, which included a follow-up phase. During the last two weeks of treatment, 8% of patients in the CPP-109 arm were cocaine free compared to 5% in the placebo arm. Needless to say, the result was not statistically significant.