SEPRACOR REPORTS 2ND QTR 2005 NET LOSS OF $7.4 MILLION.

Sepracor Inc. (Nasdaq: SEPR), Marlborough, Mass., has announced its consolidated financial results for the second quarter of 2005. For the three months ended June 30, 2005, Sepracor's consolidated revenues were $185.1 million, of which revenues from pharmaceutical product sales were $166.7 million ($83.2 million for sales of XOPENEX(R) brand levalbuterol HCl Inhalation Solution and $83.5 million for sales of LUNESTA(TM) brand eszopiclone, which was launched in April 2005).

The net loss for the second quarter of 2005 was $7.4 million, or $0.07 per share. These consolidated results compare with consolidated revenues of $70.0 million, of which revenues from pharmaceutical product sales (XOPENEX Inhalation Solution) were $57.5 million, and a net loss of $81.1 million, or $0.93 per share, for the three months ended June 30, 2004.

For the six months ended June 30, 2005, Sepracor's consolidated revenues were $304.1 million, of which revenues from pharmaceutical product sales were $273.4 million ($189.9 million for sales of XOPENEX Inhalation Solution and $83.5 million for sales of LUNESTA), and the net loss was $30.0 million, or $0.29 per share. These consolidated results compare with consolidated revenues of $169.4 million, of which revenues from pharmaceutical product sales (XOPENEX Inhalation Solution) were $142.5 million, and a net loss of $131.6 million, or $1.53 per share, for the six months ended June 30, 2004.

As of June 30, 2005, Sepracor had approximately $920 million in cash and short- and long-term investments.

Commercial Operations

LUNESTA brand eszopiclone - During the quarter, Sepracor began full-scale commercial launch of LUNESTA 1 mg, 2 mg and 3 mg tablets for the treatment of insomnia. Marketed through Sepracor's 1,250-person sales force, LUNESTA is available by prescription in the U.S.

Also during the quarter, Phase III and IV data related to LUNESTA were presented at the annual meetings of the Associated Professional Sleep Societies, the American Psychiatric Association and the International Society for Pharmacoeconomics and Outcomes Research. Among the data presented were:

-- Forecasting the Impact of Adding a New Drug on Formulary Using Medical Claims Data and Clinical Literature: A Case Study of Insomnia Treatment

-- Adjunctive Eszopiclone With Fluoxetine for Major Depressive Disorder (MDD) and Insomnia: Sleep Effects

-- Adjunctive Eszopiclone With Fluoxetine for MDD and Insomnia: Depression Effects

-- Analysis of the Treatment Effect of Eszopiclone on Sleep Parameters That Affect Next-Day Function in the Elderly

-- A Crossover Study of Eszopiclone in the Treatment of Primary Insomnia

-- Eszopiclone Co-Administered With Fluoxetine for Insomnia Associated With MDD: Effects Following Eszopiclone Discontinuation

-- Trajectory Analysis of Treatment Response Across a Twelve-Month Study of Nightly Eszopiclone in Patients With Chronic Insomnia

-- A Dose-Response Efficacy and Safety Study of Eszopiclone in the Treatment of Primary Insomnia

-- Evaluation of the Safety and Efficacy of Eszopiclone in Patients With Obstructive Sleep Apnea

In July 2005, Sepracor announced results from its Phase IIIB/IV, 410-patient, four-week, randomized, double-blind, placebo-controlled study evaluating the safety and efficacy of LUNESTA for the treatment of insomnia in perimenopausal and menopausal women suffering from insomnia. The results of this study will be presented at The North American Menopause Society's annual meeting in San Diego on Sept. 30, 2005. In this study, nightly use of LUNESTA 3 mg resulted in statistically significant improvement (p<0.01) compared with placebo in patient-reported measures of sleep latency (onset of sleep), wake time after sleep onset (WASO; a sleep maintenance measurement of the amount of time spent awake after initially falling asleep), and total sleep time for each week of the four-week study. LUNESTA was well tolerated over the treatment period.

Compared to baseline and averaged over the double-blind period, women treated with LUNESTA reported fewer nocturnal awakenings due to hot flashes than those treated with placebo (p<0.003). A physician global assessment, which evaluated the overall change in menopausal symptoms, was statistically significantly improved (p<0.0001) for women treated with eszopiclone 3 mg compared with those treated with placebo. Perimenopause in women is the transition period from normal reproductive function to complete cessation of the menstrual period, or menopause. During this transition, which can be years in duration, and continuing through to the post-menopausal period, the body experiences both physical and hormonal changes, which can be associated with a variety of symptoms. Problems sleeping and the resulting fatigue may occur due to waking up in the middle of the night because of hot flashes or the need to go to the bathroom, which can lead to trouble falling back to sleep. During this time, women may also experience trouble falling to sleep or waking up early in the morning. According to the Agency for Healthcare Research and Quality, up to 40 to 60 percent of perimenopausal, menopausal, and postmenopausal women experience sleep disturbances.

Insomnia can include difficulty falling asleep as well as difficulty maintaining sleep through the night. The recommended dosing for LUNESTA to improve sleep onset and/or maintenance is 2 mg or 3 mg for adult patients (ages 18 to 64). In older adult patients (ages 65 and older), 2 mg is recommended for improving sleep onset and/or maintenance, while the 1 mg dose is recommended for improving sleep onset in older adult patients whose primary complaint is difficulty falling asleep.

An estimated 100 million adult Americans suffer from either chronic or occasional insomnia.(a) Symptoms of insomnia include difficulty falling asleep, awakening frequently during the night, waking up too early, an inability to fall back to sleep, or awakening feeling unrefreshed. Insomnia can be a serious condition. If left untreated, it may become progressively worse and in turn potentially affect a person's emotional, mental and physical health.

XOPENEX(R) brand levalbuterol HCl - Marketed through Sepracor's sales force, XOPENEX Inhalation Solution is a short-acting bronchodilator indicated for the treatment or prevention of bronchospasm in patients 6 years of age and older with reversible obstructive airway disease, such as asthma. XOPENEX is available for use in a nebulizer at 0.31 mg and 0.63 mg dosage strengths for routine treatment of children 6 to 11 years old, and in 0.63 mg and 1.25 mg dosage strengths for patients 12 years of age and older.

Asthma is a chronic lung disorder characterized by reversible airway obstruction and the pathologic finding of airway inflammation. According to the American Lung Association, approximately 26 million Americans have been diagnosed with asthma in their lifetime. It is the most common childhood illness and affects approximately 8.6 million children in the U.S. under the age of 18.

ALLEGRA(R) brand fexofenadine HCl - Sepracor earns royalties from Aventis for sales of ALLEGRA, a nonsedating antihistamine, in the U.S. and other countries where Sepracor holds patents relating to fexofenadine (including Japan, Europe, Canada and Australia).

CLARINEX(R) brand desloratadine - Sepracor earns royalties from Schering-Plough Corporation on sales of all formulations of CLARINEX brand desloratadine in the U.S. and in other countries where Sepracor holds patents relating to desloratadine. CLARINEX is indicated for the treatment of allergic rhinitis and chronic idiopathic urticaria (CIU), also known as hives of unknown cause, in patients 12 years of age and older.

XYZAL(R)/ XUSAL(TM) brand levocetirizine - Sepracor earns royalties from UCB on sales of levocetirizine in European countries where the product is sold. Levocetirizine is marketed as XUSAL in Germany and is marketed under the brand name XYZAL in other member states of the European Union. A single isomer of ZYRTEC(R), levocetirizine is indicated for the treatment of symptoms of seasonal and perennial allergic rhinitis and CIU, in adults and children aged 6 years and older. XYZAL is also indicated for persistent allergic rhinitis, which is characterized as allergic symptoms that are present for at least four days per week, and last at least four consecutive weeks.

XOPENEX HFA(TM) (levalbuterol tartrate) MDI - On March 11, 2005, the U.S. Food and Drug Administration (FDA) approved Sepracor's New Drug Application (NDA) for XOPENEX HFA (hydrofluoroalkane) MDI (metered-dose inhaler) for the treatment or prevention of bronchospasm in adults, adolescents and children 4 years of age and older with reversible obstructive airway disease. Reversible obstructive airway disease includes respiratory disorders such as asthma and chronic obstructive pulmonary disease (COPD). An MDI is a portable, hand-held device consisting of a pressurized canister containing medication and a mouthpiece through which the medicine is inhaled.

Sepracor continues to work to resolve outstanding manufacturing issues and complete process validation work relating to XOPENEX HFA. Sepracor is targeting launch of XOPENEX HFA by the end of the year. Upon launch, Sepracor's sales force will promote XOPENEX HFA to primary care doctors, specialists including allergists and pulmonologists, and hospitals in the U.S.