ACADIA Pharmaceuticals Announces Publication in The Lancet of Pivotal Phase III Parkinson’s Disease Psychosis Trial with

  ACADIA Pharmaceuticals Announces Publication in The Lancet of Pivotal Phase
  III Parkinson’s Disease Psychosis Trial with Pimavanserin

Business Wire

SAN DIEGO -- October 31, 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, today announced the
publication of data from its pivotal Phase III -020 Study with pimavanserin in
patients with Parkinson’s disease psychosis (PDP) in the November 1, 2013
online issue of The Lancet. In the -020 Study, pimavanserin demonstrated
significant and clinically meaningful benefits and was safe and well tolerated
in patients with PDP. Pimavanserin significantly reduced psychosis and
maintained motor control in patients with PDP. Significant benefits were also
observed in exploratory measures of nighttime sleep, daytime wakefulness and
caregiver burden.

“Among Parkinson’s patients, psychosis causes great distress for patients and
caregivers and is the leading cause of institutionalization,” said Jeffrey
Cummings, M.D., Sc.D., Director of Cleveland Clinic Lou Ruvo Center for Brain
Health, and lead author. “These data indicate that pimavanserin, a selective
5-HT[2A ]inverse agonist, confers a meaningful clinical benefit in patients
with PDP and has the potential to be an important new treatment option for
this condition for which there is no approved therapy in the U.S.”

Pimavanserin met the primary endpoint in the -020 Study by demonstrating
highly significant improvement in psychosis compared to placebo on the 9-item
SAPS-PD scale (p=0.001), which was assessed by central, independent raters.
The mean change in SAPS-PD score represented a 37% improvement for
pimavanserin versus 14% for placebo (p<0.001). Pimavanserin also demonstrated
significant improvement on the full 20-item SAPS (hallucinations plus
delusions) measure (p=0.001) and on each of the separate hallucinations and
delusions domains in supportive analyses.

Significant improvements were observed for pimavanserin over placebo on
additional investigator-assessed secondary measures of psychosis benefit,
including the Clinical Global Impression Severity, or CGI-S, scale (p<0.001),
and the Clinical Global Impression Improvement, or CGI-I, scale (p=0.001). The
proportion of CGI-I responders was also higher for pimavanserin versus
placebo, (49% vs. 26%, p=0.002). Pimavanserin met the key secondary endpoint
for motoric tolerability as measured using Parts II and III of the Unified
Parkinson’s Disease Rating Scale, or UPDRS. Caregivers in the pimavanserin
group also reported significant reduction in caregiver burden (p=0.002), and
participants reported significant improvements on nighttime sleep (p=0.045)
and daytime wakefulness (p=0.012) for pimavanserin over placebo in exploratory
analyses.

Consistent with previous studies, pimavanserin was well tolerated in the -020
Study with no significant safety concerns or impairment in motor function. The
most common treatment-emergent adverse events were urinary tract infection
(13.5% PIM vs. 11.7% PBO) and falls (10.6% PIM vs. 8.5% PBO). Although adverse
event discontinuations were higher in the pimavanserin group compared to
placebo, overall drop-outs in the -020 Study were low compared to other
reported studies in PDP and similar neuropsychiatric conditions.

“The -020 Study results presented in The Lancet suggest that pimavanserin has
the potential to provide a safe, well-tolerated, and effective alternative to
existing antipsychotic drugs. Current atypical antipsychotics are often used
off-label to treat PDP despite increasing evidence that they are associated
with serious safety issues and are poorly tolerated in this fragile and
elderly patient population,” said Clive Ballard, M.D., Professor of Age
Related Diseases at King’s College London.

Phase III -020 Study Design

The pivotal Phase III trial, referred to as the -020 Study, was a
multi-center, double-blind, placebo-controlled study designed to evaluate the
efficacy, tolerability and safety of pimavanserin as a treatment for patients
with Parkinson’s disease psychosis. A total of 199 patients were enrolled in
the study and randomized on a one-to-one basis to receive either 40 mg of
pimavanserin or placebo once-daily for six weeks, following a two-week
screening period including brief psycho-social therapy. Patients also received
stable doses of their existing anti-Parkinson’s therapy throughout the study.
The primary endpoint of the -020 Study was antipsychotic efficacy as measured
using the “SAPS–PD” scale, which consists of nine items from the
hallucinations and delusions domains of the Scale for the Assessment of
Positive Symptoms (SAPS). Additional secondary and supportive measures of
efficacy were measured using the Clinical Global Impression Severity (CGI-S)
scale, the Clinical Global Impression Improvement (CGI-I) scale, and the full
20-item SAPS. Exploratory measures of nighttime sleep, daytime wakefulness,
and caregiver burden were measured using the Scales for Outcome in Parkinson’s
Disease - Nighttime Sleep (SCOPA-NS), the Scales for Outcome in Parkinson’s
Disease - Daytime Sleep (SCOPA-DS), and the Caregiver Burden Scale (CBS),
respectively. Motoric tolerability was a key secondary endpoint in the study
and was measured using Parts II and III of the Unified Parkinson’s Disease
Rating Scale (UPDRS).

About Pimavanserin

Pimavanserin is ACADIA’s proprietary small molecule that acts selectively as
an antagonist/inverse agonist on serotonin 5-HT[2A ]receptors. ACADIA has
successfully completed a pivotal Phase III trial with pimavanserin for
Parkinson’s disease psychosis (PDP), potentially positioning it to be the
first drug approved in the United States for the treatment of this disorder.
Pimavanserin is also in Phase II development for Alzheimer’s disease psychosis
(ADP) and has completed a Phase II trial as a co-therapy in schizophrenia.
Pimavanserin is formulated as a tablet and is administered orally once-a-day.
ACADIA discovered pimavanserin and holds worldwide rights to this new chemical
entity.

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, or 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, the benefits to be derived from ACADIA’s product candidates, in each
case including pimavanserin, the potential for pimavanserin to be approved for
PDP or be an important new treatment option for PDP sufferers, and the
potential of pimavanserin to provide a safe, well-tolerated, and effective
alternative to existing antipsychotic drugs. 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, Investor Relations
(858) 558-2871