Data presented at the APA Annual Meeting

Pharmacogenetic analysis in a Phase III trial studying the efficacy of iloperidone in acute schizophrenia identified six single nucleotide polymorphisms (SNPs) associated with efficacy of iloperidone.

• The highest specificity and positive predictive value were observed with rs11851892 (NPAS3) with a change from baseline to endpoint PANSS-T score of -20.12 (p=0.000093)

• The highest sensitivity and negative predictive value were seen with rs9643483 (XKR4) with a change from baseline to endpoint PANSS-T score of -15.02 (p=0.00017)

• None of the six SNPs was significantly associated with response to ziprasidone
  
  

The combination of six markers defined several groups of patients with different probability of response to iloperidone. Twenty-seven percent of patients carried at least five of the most favorable genotypes and constituted a group of iloperidone responders who showed a response of greater magnitude and of an earlier onset as compared to patients with alternative genetic make-up. These genetic markers for iloperidone response were not correlated to prediction of ziprasidone response. These results, while requiring further confirmation, are encouraging and suggest that pharmacogenetics may have the potential to identify likely responders and differentiate antipsychotics.

"Whenever a new antipsychotic becomes available, it may be possible to help some of our patients who had not responded well to other available medications," said Dr. Weiden. "Based on my experience, individual patients may have very different responses to individual antipsychotics and one of the frustrating parts of trying new medications is that we have no good way of knowing in advance which patient will respond well to a medication. Research to help clinicians determine whether one medication might work better than another for a patient would be a big advancement."

"Pharmacogenetics research to help identify markers of schizophrenia treatment response is fundamental and may help usher us into an era of personalized treatments in schizophrenia and bring us one step closer to providing the optimal treatment for each patient," said Paolo Baroldi, M.D., Ph.D., Chief Medical Officer, Vanda Pharmaceuticals Inc.

About Vanda Pharmaceuticals Inc.

Vanda Pharmaceuticals Inc. is a biopharmaceutical company focused on the development and commercialization of clinical-stage product candidates for central nervous system disorders. The company has three product candidates. Vanda's lead product candidate, iloperidone, is under clinical investigation for the treatment of schizophrenia, but has not been approved by any regulatory authority. The FDA accepted Vanda's iloperidone New Drug Application (NDA) for filing in November 2007 and Vanda expects a decision from the FDA on or about July 27, 2008. Vanda's second product candidate, tasimelteon (VEC-162), is a compound for the treatment of sleep and mood disorders, which is currently in Phase III for chronic primary insomnia. Vanda's third product candidate, VSF-173, is a compound for the treatment of excessive sleepiness in Phase II. For more on Vanda Pharmaceuticals Inc., please visit http://www.vandapharma.com.