Cytokinetics Announces Selection of Development Compound That Activates the Skeletal Sarcomere

SOUTH SAN FRANCISCO, CA, Apr 17 (MARKET WIRE) --
Cytokinetics, Incorporated (NASDAQ: CYTK) announced today the selection
of a development compound that is directed towards a molecular target in the
skeletal sarcomere. This compound is a highly specific small molecule
activator of the troponin complex, increasing its sensitivity to calcium, and
subsequently leading to an increase in skeletal muscle contractility. This
mechanism of action has demonstrated encouraging pharmacological activity in
non-clinical models that may relate to potential treatment of diseases
associated with aging and neuromuscular wasting. The potential drug candidate
is the fifth development compound to emerge from the company's research
activities which have focused on discovering novel therapeutics directed towards
cytoskeletal biology.

"We are pleased to announce the advancement of this additional development
compound
which has arisen from Cytokinetics' research activities," stated David J.
Morgans, Jr., Ph.D., Cytokinetics' Executive Vice President, Drug Discovery
and Development. "An activator of the skeletal sarcomere, in this case a
troponin-based activator, has the potential to define a new mechanistic
approach to address serious diseases associated with skeletal muscle deficits.
In
the contexts of aging, muscle wasting syndromes and various neuromuscular
diseases, treatment options are quite limited and unmet clinical needs are
significant."

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 and
neuromuscular wasting. 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.

"The advancement of this program underscores the tractability, continued
innovation
and promise of emerging cytoskeletal pharmacology," stated Robert I. Blum,
Cytokinetics' President and CEO. "Adding another potential drug candidate to
our
portfolio of development compounds validates our continuing investments in
research and may provide additional growth opportunities for the company."

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' development efforts are
primarily
directed to advancing multiple drug candidates through clinical trials with
the objective of determining the intended pharmacodynamic effect or effects
in two principal diseases: heart failure and cancer. 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
performingjoint 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. Cytokinetics' cancer program is focused on mitotic
kinesins, a family of motor proteins essential to cell division. Under a
strategic alliance established in 2001, Cytokinetics and GlaxoSmithKline
(GSK) are conducting research and development activities focused on the
potential
treatment of cancer. Cytokinetics is developing two novel drug candidates that
have
arisen from this program, ispinesib and SB-743921, each a novel inhibitor of
kinesin spindle protein (KSP), a mitotic kinesin. Cytokinetics believes
that ispinesib has demonstrated clinical activity in Phase II monotherapy
clinical
trials in breast cancer, ovarian cancer and non-small cell lung cancer and
recently initiated an additional Phase I/II clinical trial of ispinesib as
monotherapy as a first-line treatment in chemotherapy-naive patients with
locally advanced or metastatic breast cancer on a more dose-dense schedule than
previouslystudied. Cytokinetics is also conducting a Phase I/II trial of
SB-743921 on a
similar more dose-dense schedule in non-Hodgkin and Hodgkin lymphomas. GSK has
obtained an option for the joint development and commercialization of ispinesib
and
SB-743921. Cytokinetics and GSK are conducting collaborative research
activities
directed to the mitotic kinesin centromere-associated protein E (CENP-E).
GSK-923295, a CENP-E inhibitor, is being developed under the strategic alliance
by
GSK, subject to Cytokinetics' option to co-fund certain later-stage
development activities and to co-promote any resulting approved drug in North
America. GSK began a Phase I clinical trial with GSK-923295 in 2007. In
April 2008, Cytokinetics announced the selection of a potential drug candidate
directedtowards skeletal muscle contractility which may be developed as a
potentialtreatment for diseases associated with neuromuscular wasting. All of
these
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.
Cytokinetics' focus on the cytoskeleton enables it to develop novel and
potentially safer and more effective classes of drugs directed at treatments
for cancer and cardiovascular disease. 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").
Cytokineticsdisclaims any intent or obligation to update these forward-looking
statements, and claims
the protection of the Safe Harbor for forward-looking statements contained in
the Act. Examples of such statements include, but are not limited to,
statements relating to the potential benefits of Cytokinetics' drug
candidates and potential drug candidates, including the potential utility and
therapeutic role of skeletal sarcomere activators, potential growth
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 approval, production and marketing of
Cytokinetics' drug candidates that could slow or prevent clinical development,
product approval or market acceptance, 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 clinical trials may be
difficult or delayed, Cytokinetics' drug candidates may have unexpected 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
andmaintain patent or trade secret protection for its intellectual property;
potential
decisions by GSK to postpone or discontinue development efforts for GSK-923295;
Cytokinetics may incur unanticipated research and development and other costs
or be unable to obtain additional financing if necessary; standards of care
may change or others may introduce products or alternative therapies for the
treatment of indications Cytokinetics' drug candidates and potential drug
candidates currently or potentially target; and risks and uncertainties relating
to the timing and receipt of funds under Cytokinetics' collaborations. For
further information regarding these and other risks related to Cytokinetics'
business, investors should consult Cytokinetics' filings with the Securities and
Exchange Commission.

Contacts:
Scott R. Jordan (Media)
Director, Corporate Development
(650) 624-3000

Christopher S. Keenan (Investors)
Director, Investor Relations
(650) 624-3000

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