Cytokinetics Announces Updates Relating to Muscle Biology Research and Non-Clinical Development Programs

SOUTH SAN FRANCISCO, CA, Jan 12 (MARKET WIRE) --
Cytokinetics, Incorporated (NASDAQ: CYTK) announced updates relating to
its internal research programs directed to muscle biology. The company
announced that it plans to file an IND in 2009 for CK-2017357, a skeletal
muscle activator, which had been selected for development in April 2008.
This compound is the lead potential drug candidate which has arisen from
the company's skeletal muscle activator program. The company also
announced that is has recently designated a second skeletal muscle
activator from this research program for development. In addition,
Cytokinetics announced the selection of a small molecule inhibitor of
smooth muscle myosin for development. This potential drug candidate is
expected to enter IND-enabling studies in 2009.

CK-2017357 and the backup skeletal muscle activator are structurally
distinct small molecule activators of the troponin complex. Activation of
the troponin complex by each of these compounds increases its sensitivity
to calcium, subsequently leading to an increase in skeletal muscle
contractility. This mechanism of action has demonstrated encouraging
pharmacological activity in preclinical models that may relate to the
potential treatment of diseases associated with aging, muscle wasting, and
neuromuscular dysfunction. Cytokinetics generally seeks to identify
backups for its lead drug candidates in order to mitigate any development
risks that might be encountered with a lead development compound.

The development compound selected for advancement in the smooth muscle
research program is a direct small molecule inhibitor of smooth muscle
myosin, the motor protein responsible for the contraction of the smooth
muscle cells that surround airways in the lungs and the blood vessels that
control blood pressure. By inhibiting the function of the myosin motor
central to the contraction of smooth muscle, this potent small molecule
directly leads to the relaxation of contracted smooth muscle. Specifically
designed for inhaled delivery applications, this development compound has
demonstrated encouraging pharmacological activity in preclinical models
that may relate to its uses as a novel mechanism bronchodilator for the
potential treatment of diseases, such as pulmonary hypertension, asthma
and chronic obstructive pulmonary disease (COPD).

"We are pleased with our progress in both of our skeletal and smooth
muscle programs, most notably our preparations towards the filing of an
IND for CK-2017357. The selection of a back-up compound that may
potentially follow behind CK-2017357 is intended to help mitigate any
development risks associated with our lead candidate thereby increasing
our likelihood for future drug development success in this area," stated
David J. Morgans, Jr., Ph.D., Cytokinetics' Executive Vice President,
Preclinical Research and Development. "In addition, an inhibitor of
smooth muscle myosin has the potential to define a new mechanistic
approach to address serious diseases in an established therapeutic class,
namely smooth muscle relaxants. We are looking forward to advancing this
compound in development as well."

"The advancement of these first-in-class compounds in development
underscores the continued innovation, tractability and capital-efficiency
of our muscle-biology-focused research activities," stated Robert I. Blum,
Cytokinetics' President and CEO. "We believe that expansion of our
portfolio of development compounds provides our company with growth
opportunities within a broad range of therapeutic areas and that we are
nicely positioned to progress our clinical stage drug candidates, as well
as these additional novel mechanism compounds, through important
value-enhancing milestones in 2009."

Background on Skeletal Muscle Activators

Skeletal muscle contractility is driven by the sarcomere, the fundamental
unit of skeletal muscle contraction. It is a highly ordered cytoskeletal
structure composed of skeletal muscle myosin, the cytoskeletal motor that
is directly responsible for converting chemical energy into the mechanical
force, actin, and a set of regulatory proteins, troponins and tropomyosin,
which make the actin-myosin interaction dependent on changes in
intracellular calcium levels. Cytokinetics' skeletal muscle contractility
program is focused to the discovery and development of small molecule
skeletal sarcomere activators and leverages Cytokinetics' expertise
developed in its ongoing discovery and development of cardiac sarcomere
activators, including the cardiac myosin activator, CK-1827452, now in
Phase II clinical development as a potential treatment for heart failure.
Skeletal sarcomere activators have demonstrated pharmacological activity
that may lead to new therapeutic options for diseases associated with
aging, muscle wasting, and neuromuscular dysfunction. The clinical effects
of muscle wasting, fatigue and loss of mobility can range from decreased
quality of life to, in some instances, life-threatening complications. By
directly improving skeletal muscle function, a small molecule activator of
the skeletal sarcomere may potentially enhance physical performance and
quality of life in aging patients.

Background on Smooth Muscle Inhibitors

Smooth muscle contractility is driven by the motor protein smooth muscle
myosin. A mechanochemical enzyme, smooth muscle myosin is the cytoskeletal
motor that is directly responsible for converting chemical energy into
mechanical force. Cytokinetics' smooth muscle contractility program is
focused to the discovery and development of small molecule smooth muscle
myosin inhibitors and leverages Cytokinetics' expertise in muscle function
and its application to drug discovery. This expertise has resulted in the
discovery and development of compounds that modulate the function of the
two other muscle types, cardiac and skeletal muscle. Inhaled smooth muscle
myosin inhibitors have demonstrated pharmacological activity in
preclinical models of bronchoconstriction and pulmonary vascular
constriction and may have application in diseases such as pulmonary
hypertension, asthma and COPD. Systemic administration of smooth muscle
myosin inhibitors, either orally or intravenously, has demonstrated
pharmacological activity in preclinical models of systemic vascular
constriction and may have application in systemic hypertension. Compounds
which exhibit this mechanism of action may lead to new therapeutic
options in a variety of diseases where there still exists unmet clinical
need and where, in some instances, people still suffer life-threatening
complications.

About Cytokinetics

Cytokinetics is a biopharmaceutical company focused on the discovery,
development and commercialization of novel small molecule drugs that may
address areas of significant unmet clinical needs. Cytokinetics'
cardiovascular disease program is focused to cardiac myosin, a motor
protein essential to cardiac muscle contraction. Cytokinetics' lead
compound from this program, CK-1827452, a novel small molecule cardiac
myosin activator, entered Phase II clinical trials for the treatment of
heart failure in 2007. Under a strategic alliance established in 2006,
Cytokinetics and Amgen Inc. are performing joint research focused on
identifying and characterizing activators of cardiac myosin as back-up and
follow-on potential drug candidates to CK-1827452. Amgen has obtained an
option for an exclusive license to develop and commercialize CK-1827452,
subject to Cytokinetics' development and commercial participation rights.
In April 2008, Cytokinetics announced the selection of a potential drug
candidate, CK-2017357, directed towards skeletal muscle contractility
which may be developed as a potential treatment for skeletal muscle
weakness associated with neuromuscular diseases or other conditions. In
January 2009, Cytokinetics announced the selection of a potential drug
candidate directed towards smooth muscle contractility which may be
developed as a potential treatment for diseases associated with
bronchoconstriction and vasoconstriction.

Cytokinetics' cancer program is focused on mitotic kinesins, a family of
motor proteins essential to cell division. Cytokinetics is developing two
drug candidates that have arisen from this program, ispinesib and
SB-743921, each an inhibitor of kinesin spindle protein, a mitotic
kinesin. In addition, Cytokinetics and GlaxoSmithKline are conducting
research and development activities focused on GSK-923295, an inhibitor of
centromere-associated protein E (CENP-E).

All of these drug candidates and potential drug candidates have arisen
from Cytokinetics' research activities and are directed towards the
cytoskeleton. The cytoskeleton is a complex biological infrastructure that
plays a fundamental role within every human cell. Additional information
about Cytokinetics can be obtained at www.cytokinetics.com.

This press release contains forward-looking statements for purposes of the
Private Securities Litigation Reform Act of 1995 (the "Act"). Cytokinetics
disclaims any intent or obligation to update these forward-looking
statements, and claims the protection of the Act's safe harbor for
forward-looking statements. Examples of such statements include, but are
not limited to, statements relating to Cytokinetics' research and
development activities, including planned studies, the timing and
occurrence of IND filings and the utility of backup compounds in
mitigating development risk; the potential benefits of Cytokinetics'
compounds, including the potential utility and therapeutic role of
skeletal sarcomere activators and smooth muscle inhibitors and the
potential opportunities provided by the addition of new development
compounds to Cytokinetics' portfolio; and the enabling capabilities of
Cytokinetics' cytoskeletal focus. Such statements are based on
management's current expectations, but actual results may differ
materially due to various risks and uncertainties, including, but not
limited to potential difficulties or delays in the development, testing,
regulatory approvals for trial commencement, progression or product sale
or manufacturing, or production of Cytokinetics' compounds that could
slow or prevent clinical development or product approval, including risks
that current and past results of clinical trials or preclinical studies
may not be indicative of future clinical trials results, patient
enrollment for or conduct of clinical trials may be difficult or delayed,
Cytokinetics' compounds may have adverse side effects or inadequate
therapeutic efficacy, the U.S. Food and Drug Administration or foreign
regulatory agencies may delay or limit Cytokinetics' or its partners'
ability to conduct clinical trials, and Cytokinetics may be unable to
obtain or maintain patent or trade secret protection for its intellectual
property; Amgen may elect not to exercise its option with respect to
CK-1827452; Cytokinetics may incur unanticipated research and development
and other costs or be unable to obtain additional financing necessary to
conduct development of its products; standards of care may change
rendering Cytokinetics' compounds obsolete; others may introduce products
or alternative therapies for the treatment of indications Cytokinetics'
compounds may target; and risks and uncertainties relating to the timing
and receipt of payments from its partners, including option fees,
milestones and royalties on future potential product sales under
Cytokinetics' collaboration agreements with such partners. For further
information regarding these and other risks related to Cytokinetics'
business, investors should consult Cytokinetics' filings with the
Securities and Exchange Commission.

Contacts:
Christopher S. Keenan (Investors and Media)
Director, Investor Relations
(650) 624-3000

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