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EPIX Pharmaceuticals Reports Preliminary Findings from Phase 1b Clinical Trial of Novel 5-HT6 Drug Candidate

LEXINGTON, Mass.--(BUSINESS WIRE)--Oct 29, 2007 - EPIX Pharmaceuticals, Inc. (NASDAQ: EPIX) today announced statistically significant results from its Phase 1b clinical trial of PRX-07034 in obesity, the company's internally-discovered, novel 5-HT6 antagonist being developed for obesity, Alzheimer's disease and cognitive impairment associated with schizophrenia. Findings from the randomized, double-blind, placebo-controlled trial of 21 obese, but otherwise healthy, adults demonstrated that adults taking 600mg PRX-07034 twice-daily (n=11) for 28 days lost an average of 0.45 kg (1 pound), while adults on placebo (n=10) gained 1.37 kg (3 pounds) during the same period; p less than 0.005.

Key Findings:

-- After 28 days of dosing, the average difference in weight in the intent-to-treat population between subjects receiving PRX-07034 and those receiving matched placebo was 1.82kg; p less than 0.005

-- After 42 days - the 28-day dosing period and a 14-day follow-up period - subjects on PRX-07034 (n =10) lost an average of 0.26 kg overall compared to an average of 1.25 kg gained by placebo (n=10) patients; p less than 0.005

-- PRX-07034 was associated with a significant reduction in serum leptin levels, a marker of fat stores in the body (p less than 0.036)

-- Overall, only one of the 10 subjects on placebo (10%) lost any weight during the trial, while seven of the 11 subjects on PRX-07034 (approximately 64%) lost weight

-- PRX-07034 appeared well-tolerated and there were no serious adverse events reported; an increase in corrected QT interval (QTc) was apparent at the dose tested, with a mean increase over the duration of the study of 10.7 msec for the drug group versus a decrease of 1.7 msec for the placebo group

"We are very excited about the level of weight loss seen for PRX-07034 in an obesity indication," said Michael G. Kauffman, M.D., Ph.D., chief executive officer of EPIX. "In this 28-day study, not only did the adults on PRX-07034 lose weight while those on placebo gained weight, but they were able to do so without any constraints on eating habits. We also note that subjects in this study did not follow any pre-specified dietary or exercise program."

This Phase 1b trial was designed primarily to study the safety, tolerability and pharmacokinetics of a 600mg dose administered orally twice daily for 28 days in a population of obese, but otherwise healthy, adults (average weight 104.7 kg or 230 pounds).

Although there was evidence of QT prolongation in the ECG in subjects who received drug in the study, there were no corresponding clinical adverse events reported. Further development of the drug is expected to be conducted using the R-enantiomeric form of the drug because the Company believes, based on preclinical data, that the S-enantiomer is predominantly responsible for these QT findings.

Throughout the course of the trial, PRX-07034 appeared well-tolerated and there were no serious adverse events reported. Of the full intent-to-treat population of 21 adults, one patient on drug discontinued the trial due to a rash that resolved rapidly. There were no discontinuations on placebo.

The 21-person trial, which was conducted in an outpatient setting (subjects spent three nights of the total 28-day trial as inpatients to accommodate measurements and physician examinations), included secondary endpoint measures to assess potential effects on body weight, hunger and satiety and exploratory endpoint measures of cognitive function.

EPIX is continuing to gather and analyze findings from the Phase 1b trial, including data for additional secondary and exploratory endpoints including cognitive assessments.

Earlier this year, EPIX reported statistically significant improvements in cognitive function and trends in weight loss from a Phase 1b trial of PRX-07034 in doses up to 600mg once daily administered for 28 days. In that trial, PRX-07034 met the primary endpoint of safety and tolerability with no dose-limiting toxicity, no serious adverse events and no patient withdrawals.

PRX-07034 Selected for TURNS Clinical Trial

EPIX also announced today that PRX-07034 has been selected by the Treatment Units for Research on Neurocognition and Schizophrenia (TURNS), a project of the U.S. National Institute of Mental Health, for a future clinical trial to be conducted in conjunction with TURNS. EPIX will work with TURNS to develop the trial protocol and timeline. TURNS assesses and selects those compounds it feels are important to the study and treatment of neurocognitive disorders and schizophrenia. A collaborative trial could start as early as 2Q08.

Additional Clinical Updates

EPIX recently announced that it has completed enrollment in two Phase 2 clinical trials - its Phase 2b trial of PRX-00023 in Major Depressive Disorder (MDD), for which EPIX now expects to report data in 1Q08, and its Phase 2a clinical trial of PRX-03140 in Alzheimer's disease, with results expected by the end of this year.

Today's Conference Call Notice

EPIX has scheduled an investor conference call for today, October 29, 2007, at 4:30 p.m. EDT to further discuss these data and clinical updates. The live webcast - which will include accompanying presentation slides - can be accessed by visiting the investor relations section of EPIX's website at The call can be accessed by dialing 1-866-770-7125 (domestic) or 1-617-213-8066 (international) five minutes prior to the start time and providing the pass code 73371921. A replay of the call will be available on the EPIX website approximately two hours after completion of the call and will be archived, along with the slide presentation, for 30 days.

Upcoming Presentations

Andrew Uprichard, M.D., president and head of research and development at EPIX, is scheduled to present at the CIBC World Markets 18th Annual Healthcare Conference on Monday, November 5, 2007 at 10:55 a.m. EST at The Waldorf-Astoria in New York City. The presentation will be webcast live and can be accessed on the EPIX website,, in the investor relations section. A replay will be available approximately twenty-four hours after the presentation and will be archived on the company's website for two weeks.

About PRX-07034

PRX-07034 is a novel, highly selective, small-molecule antagonist of a specific G-protein coupled receptor (GPCR) known as 5-HT6, which was discovered by EPIX using its proprietary in silico drug discovery platform. PRX-07034 has shown cognitive-enhancing properties in preclinical animal models of memory impairment, as well as reductions of both food intake and body weight in several preclinical animal models of obesity. The human 5-HT6 receptor is found predominantly in the central nervous system with little or no expression in peripheral tissues, which may result in fewer peripheral side effects.

About EPIX

EPIX Pharmaceuticals is a biopharmaceutical company focused on discovering and developing novel therapeutics through the use of its proprietary and highly efficient in silico drug discovery platform. The company has a pipeline of internally-discovered drug candidates currently in clinical development to treat diseases of the central nervous system and lung conditions. EPIX also has collaborations with leading organizations, including GlaxoSmithKline, Amgen, Cystic Fibrosis Foundation Therapeutics and Bayer Schering Pharma AG, Germany. For more information, please visit the company's website at

This news release contains express or implied forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are based on current expectations of management. These statements relate to, among other things, our expectations regarding the progress and results of our clinical development program for PRX-007034 and its efficacy, the timing of future clinical studies and the timing and content of corporate presentations. These statements are neither promises nor guarantees, but are subject to a variety of risks and uncertainties, many of which are beyond our control, and which could cause actual results to differ materially from those contemplated in these forward-looking statements. In particular, the risks and uncertainties include, among other things: risks that product candidates, including PRX-07034, may fail in the clinic or may not be successfully marketed or manufactured; risks relating to the our ability to advance the development of product candidates currently in the pipeline or in clinical trials, any failure to comply with regulations relating to our products and product candidates, including FDA requirements; failure to obtain the financial resources to complete development of product candidates; the risk that the FDA may interpret the results of our studies differently than we have; competing products may be more successful; our inability to interest potential partners in our technologies and products; our inability to achieve commercial success for our products and technologies; the possibility of delays in the research and development necessary to select drug development candidates; the risk that we may be unable to successfully secure regulatory approval of and market our drug candidates; and risks of new, changing and competitive technologies and regulations in the U.S. and internationally. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. We undertake no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or otherwise. For additional information regarding these and other risks that we face, see the disclosure contained in our filings with the Securities and Exchange Commission, including our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q.


Kim C. Drapkin, 781-761-7602
Chief Financial Officer
Pure Communications
Keri P. Mattox, 215-791-0105

Posted: October 2007