XOPENEX HFA(TM) Pediatric Data Presented at American College of Asthma Allergy & Immunology; Study Shows Improvement in FEV(1) in Asthma Patients Treated With XOPENEX HFA

Sepracor Inc. (Nasdaq: SEPR) today announced thepresentation of results of a four-week, multicenter, randomized,double-blind, placebo-controlled, parallel-group study assessingtreatment with XOPENEX HFA(TM) (levalbuterol tartrate) InhalationAerosol metered-dose inhaler (MDI), a hydrofluoroalkane (HFA) MDI,versus placebo in pediatric patients 4 to 11 years of age whoexperience bronchospasm associated with asthma. XOPENEX HFA is asingle-isomer short-acting bronchodilator that is indicated for thetreatment or prevention of bronchospasm in patients 4 years and olderwith reversible obstructive airway disease. An MDI is a portable,hand-held device consisting of a pressurized canister containingmedication and a mouthpiece through which the medicine is inhaled. Theresults of this 150-patient study were presented at the annual meetingof the American College of Allergy, Asthma & Immunology in Anaheim,Calif.

Patients in this study who were administered the short-actingbronchodilator, XOPENEX HFA, demonstrated a statisticallysignificantly greater mean peak percent change in FEV(1) from pre-doselevels (p<0.001) versus placebo. FEV(1) refers to forced expiratoryvolume in one second, which is a test of lung function. These changesin FEV(1) from pre-dose levels were also significantly greater(p<0.05) than placebo at first dose and at week four. Mean peakpercent change in FEV(1) area under the curve from pre-dose, which isa measure of both the degree and duration of change in lung function,was significantly greater (p<0.05) for the XOPENEX HFA treatment groupversus the placebo group. Treatment with XOPENEX HFA was alsoassociated with significantly less rescue medication use in terms ofboth days used per week (p<0.001) and the number of treatments per day(p<0.01) as compared to placebo. XOPENEX HFA was well tolerated duringthe treatment period; the incidence of asthma adverse events,including asthma attacks, and beta-mediated side effects were low andcomparable to placebo.

"This study supported the pediatric portion of the New DrugApplication for FDA approval of XOPENEX HFA in patients 4 years of ageand older," said Henry Milgrom, M.D., Director of the AmbulatoryPediatric Allergy Program at National Jewish Medical and ResearchCenter, Denver. "I am looking forward to prescribing XOPENEX HFA formy patients who are already on XOPENEX delivered by nebulizer. The newpreparation will be easier and more convenient to administer. Further,XOPENEX HFA will provide a new and effective treatment alternative forpatients using albuterol."

Sepracor is targeting commercial launch by the end of 2005 forXOPENEX HFA, which is indicated for the treatment or prevention ofbronchospasm in patients 4 years of age and older with reversibleobstructive airway disease.

"We have been eagerly awaiting the arrival of this new treatmentoption," said Nancy Sander, founder and President of Allergy andAsthma Network Mothers of Asthmatics. "Children with asthma will nowhave access to a new medication to treat their asthma symptoms whetherthey are at school or at home."

"The variability and frequency of asthma symptoms are oftenunpredictable and treating them effectively is the primary goal ofshort-acting beta-agonists," said William E. Berger, M.D., ClinicalProfessor, Department of Pediatrics, Division of Allergy andImmunology, University of California, Irvine. "XOPENEX HFA willprovide doctors and patients with an effective new choice to treatthese symptoms."

The XOPENEX HFA development program included approximately 1,870pediatric and adult subjects and 54 studies (preclinical andclinical). In each of the three, large-scale, pivotal Phase III trialsthat Sepracor conducted, XOPENEX HFA was well tolerated and met thetargeted efficacy endpoints in both adults and children with asthma.In the primary airway function measure, FEV(1), XOPENEX HFA producedstatistically and clinically significant improvements relative toplacebo.

Sepracor and 3M Drug Delivery Systems Division are collaboratingunder an agreement that includes scale-up, manufacturing and supply ofXOPENEX HFA. Each XOPENEX HFA canister provides 200 actuations (orinhalations).

Approximately 96 percent of the short-acting beta-agonist inhalerssold in 2004 contained chlorofluorocarbon (CFC) propellants, accordingto IMS Health information. Under provisions in the Montreal Protocolon Substances that Deplete the Ozone Layer, an international agreementthat requires the phase-out of substances that deplete the ozonelayer, MDIs containing CFC propellants would qualify for removal fromthe marketplace. In March 2005, the FDA issued its final rule for theremoval of the essential use exemption for albuterol, which currentlypermits the use of CFC-containing albuterol inhalers despiteenvironmental concerns. Under the rule, all production and sales ofalbuterol CFC MDIs in the U.S. are required to cease by the end of2008. XOPENEX HFA uses HFA technology and does not contain a CFCpropellant.

Sepracor currently markets XOPENEX Inhalation Solution for usewith a nebulizer. XOPENEX Inhalation Solution is indicated for thetreatment or prevention of bronchospasm in patients 6 years of age andolder with reversible obstructive airway disease. XOPENEX InhalationSolution is available for use in a nebulizer at 0.31 mg and 0.63 mgdosage strengths for treatment of children 6 to 11 years old, and in0.63 mg and 1.25 mg dosage strengths for patients 12 years of age andolder.

Asthma is a chronic lung disorder characterized by reversibleairway obstruction and the pathologic finding of airway inflammation.According to the 2002 National Health Interview Survey conducted bythe Centers for Disease Control and Prevention, nearly 31 millionAmericans have been diagnosed with asthma in their lifetime. It is themost common childhood illness and affects nearly 9 million children inthe U.S. under the age of 18. Short-acting bronchodilators are themost-prescribed asthma therapy among primary care physicians andpediatricians in the U.S., according to IMS Health information.

Important Safety Information

XOPENEX HFA and XOPENEX Inhalation Solution are contraindicated inpatients with a history of hypersensitivity to levalbuterol, racemicalbuterol or any other component of XOPENEX HFA or XOPENEX InhalationSolution. XOPENEX HFA and XOPENEX Inhalation Solution and otherbeta-agonists can produce paradoxical bronchospasm, which may be lifethreatening. If additional adrenergic drugs, including othershort-acting sympathomimetic bronchodilators or epinephrine, are to beadministered by any route, they should be used with caution to avoiddeleterious cardiovascular effects. Due to the cardiovascular sideeffects associated with beta-agonists, caution is generallyrecommended for patients with cardiovascular disorders (especiallycoronary insufficiency, cardiac arrhythmias and hypertension),diabetes, hyperthyroidism, or convulsive disorders. Also, see thecomplete prescribing information regarding potential drug interactionswith beta-blockers, diuretics, digoxin, or MAOI and tricyclicantidepressants.

Sepracor Inc. is a research-based pharmaceutical company dedicatedto treating and preventing human disease through the discovery,development and commercialization of innovative pharmaceuticalproducts that are directed toward serving unmet medical needs.Sepracor's drug development program has yielded an extensive portfolioof pharmaceutical compound candidates with a focus on respiratory andcentral nervous system disorders. The company's commercializationefforts are carried out by its U.S.-based, primary care andspecialty-oriented sales force, which is comprised of more than 1,400sales professionals. Sepracor's corporate headquarters are located inMarlborough, Massachusetts.

This news release contains forward-looking statements that involverisks and uncertainties, including statements with respect to thesafety, efficacy and potential benefits of XOPENEX HFA and XOPENEXInhalation Solution and successful development and expected commerciallaunch of XOPENEX HFA. Among the factors that could cause actualresults to differ materially from those indicated by suchforward-looking statements are: Sepracor's ability to fund, and theresults of, further clinical trials; the timing and success ofsubmission, acceptance and approval of additional regulatory filings;label/use changes or concerns of XOPENEX HFA or XOPENEX InhalationSolution prescribers or patients; and certain other factors that aredetailed in the company's quarterly report on Form 10-Q for thequarter ended June 30, 2005 filed with the Securities and ExchangeCommission.

In addition, the statements in this press release representSepracor's expectations and beliefs as of the date of this pressrelease. Sepracor anticipates that subsequent events and developmentsmay cause these expectations and beliefs to change. However, whileSepracor may elect to update these forward-looking statements at somepoint in the future, it specifically disclaims any obligation to doso. These forward-looking statements should not be relied upon asrepresenting Sepracor's expectations or beliefs as of any datesubsequent to the date of this press release.

Xopenex HFA is a trademark and Xopenex is a registered trademarkof Sepracor Inc.

For a copy of this release or any recent release, visitwww.sepracor.com.