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Contacts: Karen McNulty Walsh, (631) 344-8350 or Peter Genzer, (631) 344-3174printer iconPrint

The following news release was issued by Catalyst Pharmaceutical Partners (CPP), the company that has licensed from Brookhaven National Laboratory the right to test a potential treatment for a variety of addictions that was originally developed and tested in pre-clinical studies at Brookhaven Lab. For more information about Brookhaven’s role in this research, contact: Karen McNulty Walsh, (631) 344-8350, kmcnulty@bnl.gov.

CPP Contact: Patrick J. McEnany, Chief Executive Officer, Catalyst Pharmaceutical , 305-529-2522, pmcenany@catalystpharma.com.

Catalyst Pharmaceutical Partners Continues Clinical Development of CPP-109 for the Treatment of Cocaine and Methamphetamine Addiction

Company Reports Final Results of U.S. Phase II Cocaine Trial and Top-Line Results of U.S. Proof-Of-Concept Methamphetamine Study

CORAL GABLES, FL, September 30, 2009 — Catalyst Pharmaceutical Partners, Inc. (Nasdaq:CPRX) today announced that the Company will continue to develop CPP-109 (Catalyst’s version ofvigabatrin) for the treatment of cocaine and methamphetamine addiction. The Company's decisionwas made after, and based upon, an in-depth review of the results obtained from its 186-patientPhase II clinical trial evaluating the use of CPP-109 for the treatment of cocaine addiction (CPP-01004) and the top-line results obtained from its 57-patient proof-of-concept study evaluating the useof CPP-109 for the treatment of methamphetamine addiction (CPP-02001). Catalyst’s decision tocontinue the development of the drug for both indications was supported by a panel of experts whorecently met and agreed with the Company's conclusion that there was sufficient evidence of safetyand efficacy to justify further development of CPP-109, based upon these trial data and previouslypublished studies of vigabatrin to treat addiction.

Cocaine Trial Results

After post-hoc analyses of vigabatrin levels in urine samples collected during the study, Catalystconcluded that less than 40% of the trial subjects were medication compliant. As a result, the studywas inadequately powered to test the protocol-specified efficacy hypotheses. On the basis of acomprehensive review of all study data, however, it was concluded that: (i) CPP-109 was safe andwell tolerated; and (ii) while there were no statistically significant differences between active andplacebo groups for the protocol-specified primary and secondary efficacy endpoints, there werepositive and consistent data trends observed in favor of CPP-109 across measures of cocaineabstinence, reduction in use, and reduction in use days.

Despite the limitations resulting from poor medication compliance by subjects, consistent trends infavor of CPP-109 over placebo were observed after the post-hoc analyses with respect to bothprimary and secondary efficacy endpoints. When corrected for poor medication compliance, thefollowing favorable outcome trends were observed: (i) the log10 benzoylecgonine (the major metaboliteof cocaine) levels measured in urine collected from subjects were consistently lower in the CPP-109treatment group during the 12 week treatment period, generally indicating a reduction of cocaine use;and (ii) in those subjects who were compliant with study medication, the differences between CPP-109 and placebo were amplified, which suggest that CPP-109 may facilitate abstinence, reduceoverall cocaine use as measured by urine benzoylecgonine levels (an objective measure of dailycocaine usage), and reduce cocaine usage days (an objective measure of dependence severity).

Consistent with previous published addiction trials, the protocol in the Company’s cocaine trialassessed subjects’ medication compliance based on self reporting and on counting the unusedmedication returned by subjects. Based on that methodology, the Company had an 85% compliancelevel. However, after post-hoc testing of urine samples from many of the trial’s subjects, the Companyhas concluded that less than 40% of the trial subjects were compliant taking their medication. As apractical matter, the low medication compliance effectively reduced the power of the study becausenot all subjects in the treatment group were actually treated. However, analyses of subject responses,corrected for poor compliance, makes the response ratios observed in the Company’s trial moreconsistent with the results reported by Dr. Jonathan Brodie et al. in a double-blind, placebo-controlled,103-patient Phase II trial evaluating vigabatrin for the treatment of cocaine addiction (the results ofwhich were recently published on-line in The American Journal of Psychiatry).

Douglas Winship, Catalyst’s Vice President of Regulatory Operations, commented, “The CPP-01004clinical trial was a landmark first-in-class U.S. study and to our knowledge, the first large trialconducted in cocaine-dependent subjects of an orally administered medication in which extensivepost-hoc objective measurements of medication levels in subjects to verify compliance wereperformed. Addicted subjects are an extremely difficult and unreliable population in which to conductclinical trials. In addition, there are no established FDA guidelines for addiction trials. Based onnumerous publications of data from previous addiction trials in which historical compliance rates ofgreater than 85% as measured by pill count and self-report were reported, we believed that our trialwas sufficiently powered with 180 subjects. Unfortunately, due to the significantly lower verified actualcompliance we found in our trial, there was insufficient power to detect a statistically significantdifference between CPP-109 and placebo on the primary or secondary efficacy outcomes. We willcontinue to complete additional analysis as part of our goal to present our results at appropriatemedical conferences in the coming months.”

Methamphetamine Study Results

The methamphetamine proof-of concept study enrolled 57 subjects (29 on vigabatrin and 28 onplacebo) and there was a 2.5 times higher rate of abstinence in the last two weeks (11 and 12) of thestudy in the vigabatrin group versus placebo. While this is an encouraging trend, it was not statisticallysignificant due to the small number of subjects in the study. Catalyst further believes that medicationcompliance may have been below expectations for this study as well.

CPP-109 (Vigabatrin) Safety Results

Regarding the safety of CPP-109, no clinically significant abnormalities in visual fields and visualacuity were found in any subject in either the cocaine or the methamphetamine trial. Furthermore,additional safety tests conducted in the methamphetamine trial revealed no brain or clinicallysignificant cardiovascular abnormalities in any subject. Finally, no significant differences were foundin the rates of adverse events between the CPP-109 and placebo treated subjects in either study.

Frank Vocci, Ph.D., President, Friends Research Institute and a former Director of the Division ofPharmacotherapies and Medical Consequences of the National Institute on Drug Abuse (NIDA), whoparticipated in the experts panel, stated, “Based on expanded analyses from the Catalyst trial,compliant participants receiving vigabatrin tended to have fewer cocaine use days and generally lowercocaine metabolite levels in their urine than non-compliers. After reviewing these results and thosefrom the recently published double-blind, placebo controlled trial conducted by Dr. Jonathan Brodieand his colleagues in Mexico, I believe CPP-109’s favorable safety profile and the statisticallysignificant 3.5 times increase in the achievement of abstinence with vigabatrin treatment that hereported, strongly support continuing the clinical development program for vigabatrin.”

Patrick J. McEnany, Chief Executive Officer of Catalyst, stated, “There remains a tremendous unmetmedical need for cocaine and methamphetamine addicted patients, and we believe a safe and effective patient-specific treatment may generate considerable interest among regulatory authorities,patients, physicians, investors and potential strategic partners. Our next step will be to present ourfindings to NIDA, the investment community, and potential strategic partners to obtain the funding toconduct additional clinical trials. We remain optimistic about the prospects for CPP-109 going forwardand we are committed to aggressively pursuing our two primary objectives: (i) the continueddevelopment of CPP-109 towards a pivotal Phase III trial; and (ii) completing a high-value partnershipfor the CPP-109 program. With the addiction market potentially exceeding $1 billion and growing, webelieve CPP-109 is very competitively positioned from a safety and efficacy perspective."

Mr. McEnany concluded, “As a shareholder with a significant personal investment in the Company,my interests are aligned with the interests and concerns of every shareholder. I am deeply committedto building a successful Company."

About Catalyst Pharmaceutical Partners

Catalyst Pharmaceutical Partners, Inc. is a biopharmaceutical company focused on the developmentand commercialization of prescription drugs targeting diseases of the central nervous system with afocus on the treatment of addiction and obsessive-compulsive disorders. The Company has obtainedfrom Brookhaven National Laboratory an exclusive worldwide license for nine patents in the UnitedStates relating to the right to use vigabatrin to treat a wide variety of substance addictions andobsessive-compulsive disorders. Catalyst has also been granted rights to Brookhaven's vigabatrinrelatedforeign patents or patents pending in more than 30 countries. The Company's initial productcandidate based on vigabatrin is CPP-109. CPP-109 has been granted "Fast Track" status by theU.S. Food & Drug Administration (FDA) for the treatment of cocaine addiction. This indicates that theFDA has recognized that CPP-109 is intended for the treatment of a serious or life-threateningcondition for which there is no effective treatment and which demonstrates the potential to addressunmet medical needs. Catalyst has also recently been granted worldwide rights to another patenteddrug by Northwestern University. The Company intends to pursue development of this drug forseveral indications, including stimulant addiction and epilepsy. For more information about theCompany, go to www.catalystpharma.com.

This press release contains forward-looking statements. Forward-looking statements involve knownand unknown risks and uncertainties, which may cause the Company's actual results in future periodsto differ materially from forecasted results. A number of factors, including the Company's ability tosuccessfully obtain the financing required to perform future clinical trials of CPP-109 evaluating its usein the treatment of cocaine addiction and methamphetamine addiction, the Company's ability tosuccessfully complete such future clinical trials that it determines to undertake, the Company's abilityto successfully conduct such additional number of trials as may be required to file an NDA for CPP-109, and those other factors described in the Company's filings with the U.S. Securities and ExchangeCommission (SEC), could adversely affect the Company. Copies of the Company's filings with theSEC are available from the SEC, may be found on the Company’s website or may be obtained uponrequest from the Company. The Company does not undertake any obligation to update theinformation contained herein, which speaks only as of this date.

2009-1012  |  Media & Communications Office

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