Critical Therapeutics Announces Results of Phase I/II Trial of Intravenous Formulation of Zileuton.

LEXINGTON, Mass. -- Zileuton IV Well Tolerated at All Dose Levels and Positive Impact on Lung Function Measurements Noted

Critical Therapeutics, Inc. (Nasdaq: CRTX) today announced the results of its Phase I/II clinical trial designed to evaluate safety, tolerability and pharmacokinetics of the intravenous formulation of zileuton (zileuton IV) in patients with asthma. In addition, the trial included measurements to detect evidence of improvement in lung function. The double-blind, placebo-controlled trial enrolled 60 patients at 10 clinical sites in the United States. Patients enrolled in the trial had a mean FEV(1) (forced expiratory volume in one second) of 63 percent of predicted normal at baseline and a mean age of 40 years. Patients enrolled in the trial were randomized into four escalating dose groups (75 mg, 150 mg, 300 mg, and 600 mg), each receiving one infusion of either zileuton IV or placebo. Each of the four dose groups enrolled 15 patients, of whom 12 received zileuton IV and three received placebo. All 60 patients who were randomized completed the trial.

Patients in each of the four zileuton IV cohorts showed a greater mean percentage improvement in FEV(1) than patients in the placebo group when measured at 10, 30 and 60 minute intervals after dosing. The 300 mg dose was predicted to approximate the currently approved oral dose of ZYFLO(R)(zileuton tablets). In this trial, the 300 mg dose group showed a mean improvement in FEV(1) from baseline of 13.7 percent at 60 minutes after dosing. In addition, zileuton IV was well tolerated at all doses tested with no serious adverse events reported in the trial.

Critical Therapeutics is developing zileuton IV initially for use in emergency room or urgent care centers for patients who suffer acute exacerbations of asthma. According to the Centers for Disease Control and Prevention's National Center for Health Statistics, asthma resulted in approximately 1.8 million emergency room visits in the United States in 2003.

Lyndon Mansfield, M.D., Principal Investigator and Director of Western Sky Medical Research in El Paso, Texas, stated, "I believe that the results from this Phase I/II trial are promising and support the further development of the drug for patients suffering acute exacerbations of asthma. I am particularly encouraged about the opportunities for zileuton IV in emergency and urgent care settings where there has not been a new treatment paradigm in a number of years."

"The onset of action of bronchodilation with oral zileuton correlates with peak blood concentrations," stated Walter Newman, Chief Scientific Officer of Critical Therapeutics. "If this is also true with zileuton IV, it could improve current emergency room management of this difficult-to-treat asthma patient population."

Frank Thomas, President of Critical Therapeutics, stated "We are pleased with the results that we have seen from this trial to date and will be examining the pharmacokinetic data when it becomes available next month. Following completion of the full analysis, we will determine the next development step for this program, including the appropriate doses for further examination. Our focus continues to be on advancing the programs we believe will provide the greatest value to patients and our shareholders."

About Zileuton / ZYFLO(R) (Zileuton tablets)

Zileuton inhibits 5-lipoxygenase (5-LO), an enzyme that catalyzes the formation of leukotrienes from arachidonic acid. 5-LO is the main enzyme responsible for the production of leukotrienes, a family of inflammatory mediators that can trigger asthma symptoms, including inflammation, swelling, bronchoconstriction and mucus secretion.

ZYFLO is indicated for the prevention and chronic treatment of asthma in adults and children 12 years of age and older. ZYFLO is the only 5-LO inhibitor approved for marketing by the U.S. Food and Drug Administration.

ZYFLO is not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmaticus. Mild to moderate side effects associated with the use of ZYFLO are abdominal pain, upset stomach and nausea. A small percentage of patients treated with ZYFLO show an increased release of a liver enzyme known as ALT. As a result, the level of liver enzymes in patients treated with ZYFLO should be measured by a simple blood test. It is recommended that physicians perform this test before administering ZYFLO and repeat the test on a regular basis while patients are on the medication. ZYFLO is contraindicated in patients with active liver disease or transaminase elevations greater than or equal to three times the upper limit of normal. For full prescribing information, please visit www.crtx.com/pat_pi.html or call the Company's toll free telephone number 1-866-835-8216 to request medical information.

About Critical Therapeutics

Critical Therapeutics, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of products for respiratory, inflammatory and critical care diseases. The Company owns worldwide rights to the asthma drug ZYFLO(R) (zileuton tablets), as well as other formulations of zileuton. ZYFLO is the only 5-lipoxygenase inhibitor approved for marketing by the U.S. Food and Drug Administration. The Company's commercialization efforts for ZYFLO are carried out by its specialty sales force. Critical Therapeutics also is developing treatments directed toward the severe inflammatory response in acute diseases and conditions that lead to admission to the emergency room or intensive care unit, and acute exacerbations of other chronic diseases that frequently lead to hospitalization. For more information, please visit www.crtx.com.

Forward-Looking Statements

Any statements in this press release about future expectations, plans and prospects for Critical Therapeutics, Inc., including, without limitation, statements regarding our plans for the clinical development of zileuton IV; the progress and timing of our drug development programs and related trials, including for zileuton IV; the efficacy of our drug candidates; the prospects, plans and objectives of management; and all other statements that are not purely historical in nature, constitute "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Without limiting the foregoing, the words "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "plan," "project," "should," "will," "would" and similar expressions are intended to identify forward-looking statements. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including risks and uncertainties relating to: conducting clinical trials, including difficulties or delays in the completion of patient enrollment, data collection or data analysis; the results of preclinical studies and clinical trials with respect to our products under development and whether such results will be indicative of results obtained in later clinical trials; the timing and success of submission, acceptance and approval of our regulatory filings, including, without limitation, the New Drug Application (NDA) submission for the controlled-release tablet formulation of zileuton (zileuton CR); our ability to transition our management team effectively; our ability to successfully market and sell ZYFLO(R) (immediate-release tablet formulation of zileuton) and, if approved, zileuton CR; our ability to develop and maintain the necessary sales, marketing, distribution and manufacturing capabilities to commercialize ZYFLO and, if approved, zileuton CR; patient, physician and third-payer acceptance of ZYFLO and, if approved, zileuton CR as safe and effective therapeutic products; adverse side effects experienced by patients taking ZYFLO and, if approved, zileuton CR; our heavy dependence on the commercial success of ZYFLO and zileuton CR; our ability to obtain the substantial additional funding required to conduct our research, development and commercialization activities; our dependence on our strategic collaboration with MedImmune, Inc.; and our ability to obtain, maintain and enforce patent and other intellectual property protection for ZYFLO, our drug candidates and our discoveries. These and other risks are described in greater detail in the "Risk Factors" section of our most recent Quarterly Report on Form 10-Q and other filings that we make with the Securities and Exchange Commission (SEC). If one or more of these factors materialize, or if any underlying assumptions prove incorrect, our actual results, performance or achievements may vary materially from any future results, performance or achievements expressed or implied by these forward-looking statements.

In addition, the statements in this release reflect our expectations and beliefs as of the date of this release. We anticipate that subsequent events and developments will cause our expectations and beliefs to change. However, while we may elect to update these forward-looking statements publicly at some point in the future, we specifically disclaim any obligation to do so, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this release.

ZYFLO(R) is a registered trademark of Critical Therapeutics, Inc.