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ACADIA Pharmaceuticals Reports Results From Phase II Study of ACP-103 in Schizophrenia Patients With Haloperidol-Induced Akathisia

SAN DIEGO, Dec. 1 /PRNewswire-FirstCall/ -- ACADIA Pharmaceuticals Inc. (Nasdaq: ACAD), a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders, today reported results from a Phase II study that showed that ACP-103 reduced haloperidol-induced akathisia, a debilitating extrapyramidal side effect, in patients with schizophrenia.

This study is one of two Phase II clinical trials in ACADIA's program using ACP-103 adjunctively with other antipsychotic drugs to provide an improved therapy for schizophrenia patients. The study involved 34 patients with schizophrenia and was designed to evaluate the ability of ACP-103 to treat akathisia, a side effect often induced by antipsychotic drugs. In addition to this study, ACADIA is currently conducting a Phase II trial with up to 400 patients, which is designed to evaluate the ability of ACP-103 to improve both the efficacy and safety profile of current antipsychotic drugs.

"We are encouraged by the ability of ACP-103 to treat haloperidol-induced akathisia in patients with schizophrenia," said Uli Hacksell, Ph.D., ACADIA's Chief Executive Officer. "This study is an important demonstration of our ACP-103 adjunctive therapy approach to improve the quality of care for patients suffering from schizophrenia."

Trial Design

The double-blind, randomized, placebo-controlled Phase II study enrolled 34 patients with a clinical diagnosis of schizophrenia or schizoaffective disorder, who also experienced haloperidol-induced akathisia. Results from the study presented in the accompanying table are based on 30 patients who completed the study protocol and exclude 4 subjects who had major protocol violations. Fourteen of these 30 patients received once-daily oral administration of 60 mg of ACP-103 and 16 were administered placebo over a five-day period. Subjects were maintained on their pre-study dose of haloperidol during the course of the study.

Patients were evaluated using the Barnes Akathisia Scale (BAS), a four-item rating scale widely used to assess this particular side effect of antipsychotic drugs. This scale consists of the following items: objective akathisia (Item 1), subjective awareness of restlessness (Item 2), subjective distress related to restlessness (Item 3), and global clinical assessment of akathisia (Item 4). Results from the study reflect measurements with the BAS performed on day 1, day 3, and day 5.

Trial Results

Overall, the results of the study showed that ACP-103 reduced akathisia relative to placebo. There were no statistically significant differences between ACP-103-treated and placebo-treated subjects for BAS Item 4 on day 5, a priori defined as the primary outcome measure of the study, due to a large placebo response. However, ACP-103 significantly reduced BAS Item 1 on day 5 (p = 0.04) and there were statistically significant improvements (p<0.05) or statistical trends (p<0.1) on day 3 for Item 1 (p = 0.06), Item 2 (p = 0.02), Item 3 (p = 0.09), and the BAS Total (all Items: p = 0.03).

The study was also used to explore the effects of ACP-103 on other measures, which were not part of the inclusion criteria. No significant effects were observed on extrapyramidal side effects, other than akathisia, or on plasma prolactin levels. Also, as expected because of the short treatment duration, there were no significant effects on positive or negative symptoms of schizophrenia.

ACP-103 was safe and well tolerated and no serious adverse events were reported in the study. Most of the adverse events were mild to moderate in nature and there were no adverse events that led to discontinuation of the study drug. Plasma levels of ACP-103 in patients in this study were consistent with levels found in ACADIA's previous studies with ACP-103 both in healthy volunteers and patients with Parkinson's disease. Furthermore, there was no evidence of a pharmacokinetic interaction between haloperidol and ACP-103.

Table Showing Results of ACP-103 on Haloperidol-Induced Akathisia Versus Placebo as Measured by the Barnes Akathisia Scale (BAS)

Objective akathisia (Item 1), subjective awareness of restlessness (Item 2), and subjective distress related to restlessness (Item 3) are rated on a scale of 0 to 3. The global clinical assessment of akathisia (Item 4) is rated on a scale of 0 to 5.

The table shows the mean change in the various measures of akathisia from baseline across the study days for ACP-103-treated and the placebo-treated groups. Negative figures indicate a reduction of that measure of akathisia. For those items that showed a statistical trend or statistically significant difference between ACP-103 and placebo, the p-values are shown (n.s. = not significant).




                               Mean change from baseline
          Barnes
        Akathisia                ACP-103       Placebo
          Scale        Day       n = 14        n = 16          p-value

         Item 1:        1         -0.1          -0.2             n.s.
        Objective       3         -0.7          -0.3             0.06
        Akathisia       5         -1.0          -0.5             0.04

         Item 2:        1         -0.3          -0.1             n.s.
        Subjective      3         -1.1          -0.3             0.02
       Awareness of     5         -1.1          -0.6             n.s.
       Restlessness

         Item 3:        1         -0.6          -0.1             0.09
        Subjective      3         -0.8          -0.3             0.09
         Distress       5         -0.9          -0.9             n.s.
        Related to
       Restlessness

         Item 4:        1         -0.4          -0.2             n.s.
          Global        3         -1.1          -0.6             n.s.
         Clinical       5         -1.4          -1.1             n.s.
      Assessment of
        Akathisia

          Total         1         -1.4          -0.6             n.s.
        Items 1-4       3         -3.6          -1.5             0.03
                        5         -4.4          -3.1             n.s.

About ACP-103

ACP-103 is a small molecule drug candidate that was discovered and is being developed by ACADIA as an adjunctive therapy for schizophrenia. ACP-103 is a potent and selective serotonin 5-HT2A inverse agonist, a compound that blocks the activity of this key target that plays an important role in the treatment of neuropsychiatric disorders. By giving ACP-103 together with other antipsychotic drugs, ACADIA believes that the drug candidate may improve the clinical profile of existing antipsychotic drugs. ACADIA is currently conducting a Phase II trial to explore the potential efficacy-enhancing and dose-sparing effects of ACP-103 given adjunctively with risperidone, a commonly prescribed atypical antipsychotic drug, and haloperidol. ACADIA is also developing ACP-103 as a therapy for treatment-induced dysfunctions in Parkinson's disease.

About Schizophrenia

Schizophrenia is a chronic disabling mental illness characterized by disturbances such as hallucinations and delusions as well as a range of negative symptoms. Despite the availability of a variety of current antipsychotic drugs with worldwide sales exceeding $14 billion, many symptoms associated with this disease are poorly addressed by existing therapies. In a landmark government study released in September 2005, researchers found that about three-quarters of the patients with schizophrenia who participated in the study stopped taking the drugs they were on because of lack of efficacy or intolerable side effects. Expanding the efficacy profile and reducing the side effects of these drugs represent important medical advances in schizophrenia therapy.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders. ACADIA currently has four drug programs in clinical development as well as a portfolio of preclinical and discovery assets directed at large unmet medical needs, including schizophrenia, Parkinson's disease, neuropathic pain and glaucoma. All of the drug candidates in ACADIA's product pipeline emanate from discoveries made using its proprietary drug discovery platform. ACADIA's corporate headquarters is located in San Diego, California and it maintains research and development operations in both San Diego and Malmo, Sweden.

Forward-Looking Statements

Statements in this press release that are not strictly historical in nature are forward-looking statements. These statements include but are not limited to statements related to the progress and timing of ACADIA's drug discovery and development programs and related trials, the safety and efficacy of ACADIA's drug candidates, and the benefits to be derived from ACADIA's technology, approach and drug candidates, in each case, including ACP-103. These statements are only predictions based on current information and expectations and involve a number of risks and uncertainties. Actual events or results may differ materially from those projected in any of such statements due to various factors, including the risks and uncertainties inherent in drug discovery, development and commercialization, collaborations with others and litigation. For a discussion of these and other factors, please refer to ACADIA's annual report on Form 10-K for the year ended December 31, 2004 filed with the United States Securities and Exchange Commission as well as other subsequent filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All forward-looking statements are qualified in their entirety by this cautionary statement and ACADIA undertakes no obligation to revise or update this press release to reflect events or circumstances after the date hereof.

Contacts:
ACADIA Pharmaceuticals Inc.
Lisa Barthelemy, Director, Investor Relations
Uli Hacksell, Ph.D., Chief Executive Officer
(858) 558-2871

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