Sepracor Presents Arformoterol Data at American Thoracic Society International Conference

Arformoterol tartrate inhalation solution is a long-actingbeta-agonist formulation for long-term maintenance treatment ofchronic obstructive pulmonary disease (COPD), including chronicbronchitis and emphysema. A New Drug Application (NDA) forarformoterol tartrate inhalation solution is currently under U.S. Foodand Drug Administration (FDA) review. The Prescription Drug User FeeAct (PDUFA) date for arformoterol is October 12, 2006. A PDUFA date isthe date by which the FDA is expected to review and act on an NDAsubmission.

Arformoterol, a single isomer of formoterol, is the firstlong-acting bronchodilator to be developed in an inhalation solutionfor use with a nebulizer, which is a machine that converts liquidmedication into a fine mist that is inhaled through a mask; otherlong-acting bronchodilators currently available in the U.S. areformulated in dry-powder inhalers.

Nebulized Arformoterol in COPD: A Prospective Phase III ClinicalTrial

This multicenter, double-blind, double-dummy, randomized Phase IIIstudy of 717 patients evaluated airway function improvement inpatients with COPD who were treated with either arformoterol 50micrograms, or (mu)g once daily, arformoterol 25 (mu)g twice daily,arformoterol 15 (mu)g twice daily, salmeterol metered-dose inhaler(SEREVENT(R)) 42 (mu)g twice daily, or placebo. Both an albuterolmetered-dose inhaler (MDI) as rescue therapy and an ipratropiumbromide MDI as supplemental medication for COPD were provided to allpatients in this study to be used on an as-needed basis. In thisstudy, patients treated with arformoterol by nebulizer demonstratedsignificant and sustained improvement in airway function over 12 weeksof treatment versus patients administered placebo.

In this study, patients treated with arformoterol (p<0.001) andsalmeterol (p<0.001) demonstrated a clinically meaningful andsignificant improvement in morning trough FEV1 over 12 weeks, versuspatients administered placebo. FEV1 refers to the amount of airforcefully exhaled in one second and is a test of lung function.Patients in each arformoterol treatment group (p<0.001) demonstratedsignificantly greater improvement than those patients administeredplacebo, in the percent change from pre-dose in the 12-hour FEV1 areaunder the curve (AUC) throughout the study. Patients treated withsalmeterol (p<0.001) also demonstrated significant improvement versusplacebo in percent change from pre-dose in 12-hour FEV1 AUC in thisstudy. Percent change in the area under the curve is one importantmeasure of the magnitude of effect in lung function improvement.

The results also demonstrated that the percentage of patients whowere treated with arformoterol who achieved a greater than or equal to10 percent improvement in FEV1 from pre-dose levels ranged from 93.7percent to 95.7 percent at Week 0 and 77.1 percent to 87.5 percent atWeek 12 versus patients administered placebo, who achieved 55.2percent at Week 0 and 47.6 percent at Week 12. The percentage ofpatients treated with salmeterol who achieved greater than or equal to10 percent improvement in FEV1 from pre-dose levels was 85.1 percentat Week 0 and 58.4 percent at Week 12. Both arformoterol andsalmeterol demonstrated adequate time to onset for maintenancetreatment of COPD: at Week 12, the time to achieve a 10 percentimprovement in FEV1 was 4 to 14 minutes for those patients treatedwith arformoterol and was 132.3 minutes for patients treated withsalmeterol. Overall, arformoterol was well tolerated in this study.

"I believe that these results offer evidence of the potentialmedical benefit of arformoterol," said James Donohue, M.D., Professorof Medicine and Division Chief of Pulmonary Diseases and Critical CareMedicine, University of North Carolina, School of Medicine, Departmentof Medicine at Chapel Hill. "Many patients with COPD already usenebulizers for their respiratory medications, and they may prefernebulization to metered-dose or dry-powder inhaler therapy. I expectthat these patients would benefit from having the option of anebulized long-acting bronchodilator for the treatment of their COPD."

A Crossover Dose-Ranging Study of Nebulized Arformoterol inPatients with COPD

Also presented were results of a 62-patient, 5-way crossover studyin patients with COPD. This study evaluated bronchodilation producedby arformoterol 9.6 (mu)g once daily, 24 (mu)g twice daily, 48 (mu)gonce daily and 96 (mu)g once daily, and salmeterol 42 (mu)g twicedaily, versus placebo. Both an albuterol MDI as rescue therapy and anipratropium bromide MDI as supplemental medication for COPD wereprovided to all patients in this study to be used on an as-neededbasis.

Patients treated with arformoterol (p<0.001) showed significantimprovement in bronchodilation as measured by change in FEV1 AUC,versus patients administered placebo. Mean percent change in FEV1 AUCfrom pre-dose was 13.8 percent for the 9.6 (mu)g dose of arformoterol,22.4 percent for the 24 (mu)g twice daily dose, 23.14 percent for the48 (mu)g dose, and 23.14 percent for the 96 (mu)g dose. Arformoterolwas well tolerated in this study.

About Arformoterol

Sepracor completed more than 100 preclinical and 16 clinicalstudies of arformoterol involving more than 2,000 patients. Among theclinical studies conducted were two 12-week pivotal studies, each withmore than 700 patients, as well as a large-scale, 12-month safetystudy. In Phase III studies, patients treated with arformoteroldemonstrated a statistically significant improvement in FEV1 versusthose patients administered placebo.

About COPD

According to the National Center for Health Statistics, COPD isthe fourth leading cause of death in the U.S., and in 2003, anestimated 11 million adults in the U.S. had COPD. Approximately 24million adults have evidence of impaired lung function, which mayindicate that COPD is under-diagnosed, according to the NationalHeart, Lung, and Blood Institute (NHLBI). COPD is a slowly progressivedisease of the airways that is characterized by a gradual loss of lungfunction. According to the NHLBI, COPD includes chronic bronchitis,chronic obstructive bronchitis and emphysema, or combinations of theseconditions. Bronchodilator medications are used to improve airflow andCOPD symptoms, and to reduce the occurrence and/or severity ofexacerbations in patients affected by COPD.

About Sepracor

Sepracor Inc. is a research-based pharmaceutical company dedicatedto treating and preventing human disease by discovering, developingand commercializing innovative pharmaceutical products that aredirected toward serving unmet medical needs. Sepracor's drugdevelopment program has yielded an extensive portfolio ofpharmaceutical products and 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. Sepracor's corporate headquarters arelocated in Marlborough, Massachusetts.

Forward Looking Statement

This news release contains forward-looking statements that involverisks and uncertainties, including statements with respect to thesafety, efficacy and potential benefits of arformoterol, the date bywhich the FDA is expected to complete its review of the arformoterolNDA and the successful development, regulatory approval and expectedcommercial launch of arformoterol. Among the factors that could causeactual results 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 outcome of theFDA's review of the arformoterol NDA and other regulatory filings; andcertain other factors that are detailed in the company's quarterlyreport on Form 10-Q for the quarter ended March 31, 2006 filed withthe Securities and Exchange Commission.

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.

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For a copy of this release or any recent release, visit Sepracor'sweb site at www.sepracor.com.