ACADIA Pharmaceuticals Announces Multiple Presentations of Data from Phase III Pimavanserin Program at the 17th International

  ACADIA Pharmaceuticals Announces Multiple Presentations of Data from Phase
  III Pimavanserin Program at the 17th International Congress of Parkinson’s
  Disease and Movement Disorders

Business Wire

SAN DIEGO -- June 18, 2013

ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical company
focused on innovative treatments that address unmet medical needs in
neurological and related central nervous system disorders, presented data
today from its Phase III program with pimavanserin for Parkinson’s disease
psychosis (PDP), including data from its pivotal -020 Study and the related,
open-label safety extension study, at a poster session at the 17^th
International Congress of Parkinson’s Disease and Movement Disorders, which is
taking place in Sydney, Australia from June 17 - 20, 2013.

“Data from our open-label safety extension study indicate that long-term
administration of pimavanserin is generally safe and well tolerated in PDP
patients and suggest that duration of antipsychotic effect may be maintained
for longer than the six weeks investigated in our pivotal -020 Study,” said
Uli Hacksell, Ph.D., ACADIA's Chief Executive Officer. “The overall efficacy
and safety profile observed to date shows that pimavanserin has the potential
to offer a new treatment option that may provide significant advantages
relative to current antipsychotics used off-label for the treatment of PDP.”

Key poster presentations:

1. “Long Term Pimavanserin Treatment for Parkinson’s Disease Psychosis (PDP):
An Interim Analysis of Safety and Tolerability Data from Study ACP-103-015.”
The interim analysis of the Phase III open-label safety extension trial (-015
Study) reflects data assembled in the database as of March 21, 2013. A total
of 458 PDP patients from 14 countries with a mean age at study-entry of 71
years had rolled over into the -015 Study from the six-week pivotal,
placebo-controlled efficacy, tolerability and safety trial (-020 Study) and
two earlier six-week placebo-controlled trials (-012 and -014 Studies). Study
evaluations occur at week 2 and at months 1, 3, 6, 9 and 12, as well as every
6 months thereafter. About half of the patients stayed in the open-label study
for more than a year. The data suggest that long-term administration of 40 mg
of pimavanserin is generally safe and well tolerated in patients with PDP. In
addition, the rate of discontinuation due to adverse events in the -015 Study
appears to be lower than that recently reported in a third-party study of
patients over 40 years old who used one of four commonly prescribed atypical
antipsychotic drugs.

Although there are no formal efficacy endpoints in the open-label -015 Study,
antipsychotic effect was measured at one month using the SAPS-PD scale and at
all study visits using the Clinical Global Impression Improvement, or CGI-I,
scale, and the Clinical Global Impression Severity, or CGI-S, scale. The CGI
data are intended to provide the investigator with information to determine
whether patients continue to derive benefit from pimavanserin during the
open-label study. Patients who entered the -015 Study from the 40 mg treatment
arm of the previous six-week studies maintained about the same mean
improvement in SAPS-PD scores one month later. Patients who entered the -015
Study from the placebo arm of the previous six-week studies displayed a marked
improvement in mean SAPS-PD scores after one month in the -015 Study.In
addition, the long-term CGI data indicate durability of treatment effect for
patients remaining in the open-label study.

2. “Improved Nighttime Sleep and Increased Daytime Wakefulness in Patients
with PD Psychosis Treated with Pimavanserin.” In addition to the assessments
of antipsychotic efficacy, effects on sleep and daytime wakefulness were
assessed in the previously reported six-week pivotal -020 Study. Although the
study did not require sleep impairment at entry, pimavanserin demonstrated a
significant improvement in nighttime sleep at weeks 4 and 6 compared to
placebo. Consistent with previous pimavanserin studies, this sleep improvement
was not accompanied by any sedation or “hang-over effect.” Instead,
pimavanserin produced a significant improvement in daytime wakefulness at week
6 compared to placebo. Patients who entered the -020 Study with severe
nighttime disturbances (i.e., those having a baseline score of at least 7 on
the Scales for Outcome in Parkinson’s Disease - Nighttime Sleep, or SCOPA-NS)
benefitted the most from pimavanserin therapy and showed highly significant
nighttime sleep improvements at weeks 2, 4 and 6 compared to placebo. The
positive effect of pimavanserin on nighttime sleep and daytime wakefulness did
not correlate with antipsychotic measures, thus indicating that the sleep and
wakefulness improvements of pimavanserin seen in the -020 Study may represent
treatment benefits independent from the antipsychotic efficacy.

About Pimavanserin

Pimavanserin is ACADIA’s proprietary small molecule that acts selectively as
an antagonist/inverse agonist on serotonin 5-HT[2A] receptors and is in Phase
III development as a potential first-in-class treatment for Parkinson’s
disease psychosis. Pimavanserin can be taken orally as a tablet once-a-day.
ACADIA discovered pimavanserin and holds worldwide rights to this new chemical
entity.

ACADIA has reported results from its pivotal Phase III -020 Study evaluating
the efficacy, tolerability, and safety of pimavanserin in patients with PDP.
Results of the study showed that pimavanserin demonstrated highly significant
antipsychotic efficacy in patients with PDP and allowed for maintained motor
control. Pimavanserin also showed significant improvements in all secondary
efficacy measures and on the exploratory measures of nighttime sleep, daytime
wakefulness, and caregiver burden. Consistent with previous studies,
pimavanserin was safe and well tolerated in the -020 Study.

In April 2013, ACADIA announced an expedited path to a New Drug Application
(NDA) filing for pimavanserin following a meeting with the Food and Drug
Administration (FDA). ACADIA is currently focused on completing the remaining
elements of its pimavanserin PDP program and is targeting an NDA submission
near the end of 2014.

About Parkinson’s Disease Psychosis

According to the National Parkinson’s Foundation, about one million people in
the United States and from four to six million people worldwide suffer from
Parkinson’s disease. Parkinson’s disease psychosis (PDP) is a debilitating
disorder that develops in up to 60 percent of patients with Parkinson’s
disease. Currently, there is no FDA-approved therapy to treat PDP in the
United States. PDP, commonly consisting of visual hallucinations and
delusions, substantially contributes to the burden of Parkinson’s disease and
deeply affects the quality of life of patients. PDP is associated with
increased caregiver stress and burden, nursing home placement, and increased
morbidity and mortality. There is a large unmet medical need for new therapies
that will effectively treat PDP without compromising motor control in patients
with Parkinson’s disease.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company focused on innovative treatments that
address unmet medical needs in neurological and related central nervous system
disorders. ACADIA has a pipeline of product candidates led by pimavanserin,
which is in Phase III development as a potential first-in-class treatment for
Parkinson's disease psychosis. ACADIA also has clinical-stage programs for
chronic pain and glaucoma in collaboration with Allergan, Inc. and two
advanced preclinical programs directed at Parkinson’s disease and other
neurological disorders. All product candidates are small molecules that
emanate from discoveries made at ACADIA. ACADIA maintains a website at
www.acadia-pharm.com to which ACADIA regularly posts copies of its press
releases as well as additional information and through which interested
parties can subscribe to receive email alerts.

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, either alone or with a partner, including clinical
trials and timing of filing an NDA, the benefits to be derived from ACADIA’s
product candidates, in each case including pimavanserin, the potential sleep
improvements or long-term antipsychotic benefits from treatment with
pimavanserin, and the potential benefits of pimavanserin in comparison to
off-label use of current antipsychotics and in comparison to commonly
prescribed atypical antipsychotics. 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, and collaborations with others, and the fact that past
results of clinical trials may not be indicative of future trial results. For
a discussion of these and other factors, please refer to ACADIA’s annual
report on Form 10-K for the year ended December31, 2012 as well as ACADIA’s
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, except as
required by law.

Contact:

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