Data on FACTIVE(R) Tablets Short-Course Therapy in Patients with Co-Morbidities Presented at Annual Meeting of Infectious Diseases Society of America.

-- Poster Details Outcome of Five-Day Therapy of FACTIVE in Patients with Community-Acquired Pneumonia --

TORONTO -- Data presented at the 44th Annual Meeting of the Infectious Diseases Society of America (IDSA) examined the outcome of short-course treatment with FACTIVE(R) (gemifloxacin mesylate) tablets, Oscient Pharmaceuticals Corporation's (Nasdaq: OSCI) lead antibiotic product, in patients with co-morbidities and community-acquired pneumonia (CAP). IDSA is an international meeting for infectious diseases experts to discuss the latest scientific and clinical developments in the field.

In a poster focused on short-course gemifloxacin therapy in CAP patients with certain risk factors, researchers analyzed data from Oscient's Phase III trial comparing a five-day course of therapy to a seven-day course of therapy of FACTIVE in CAP. A retrospective examination of the 510 patients enrolled in the study showed that 21.5% (55/256) in the five-day group and 21.7% (55/254) in the seven-day group had risk factors as defined by IDSA guidelines, including diabetes, chronic obstructive pulmonary disease and congestive heart failure. Of the 110 patients with risks factors, 75% were 65 years or older. A comparison of clinical resolution at follow-up in this sub-population showed a 90.9% response rate in the five-day group and a 92.7% response rate in the seven-day group. Gemifloxacin was generally well-tolerated with a low incidence of adverse events. FACTIVE is currently approved in the U.S. for the seven-day treatment of mild to moderate CAP.

"Understanding the impact of risk factors on clinical outcome in CAP is an important consideration when treating patients, as many are older and suffer from heart disease or other co-morbid conditions," stated Thomas File, M.D., Professor of Internal Medicine and Head of the Infectious Disease Section, Northeastern Ohio Universities College of Medicine and an author on the poster. "The clinical results seen with gemifloxacin in this trial, especially when looking at this specific sub-population, are supportive of the drug's utility in treating these patients."

Support for this poster was provided through an unrestricted education grant from Oscient Pharmaceuticals.

About Oscient Pharmaceuticals

Oscient Pharmaceuticals Corporation is a biopharmaceutical company committed to the clinical development and commercialization of novel therapeutics to address unmet medical needs. The Company is marketing FACTIVE(R) (gemifloxacin mesylate) tablets, approved by the FDA for the treatment of acute bacterial exacerbations of chronic bronchitis and community-acquired pneumonia of mild to moderate severity and ANTARA(R) 130 mg (fenofibrate) capsules, FDA-approved for the adjunct treatment of hypercholesterolemia (high blood cholesterol) and hypertriglyceridemia (high triglycerides) in combination with diet. Oscient has a novel antibiotic candidate, Ramoplanin, in advanced clinical development for the treatment of Clostridium difficile-associated disease (CDAD).

Important Safety Information about FACTIVE Tablets

The most common (more than 2% incidence) drug-related side effects reported in FACTIVE clinical trials were diarrhea (3.6%), rash (2.8%) and nausea (2.7%). In clinical trials, drug-related rash was reported in 2.8% of patients receiving gemifloxacin and was more commonly observed in patients less than 40 years of age, especially females. The incidence of rash increases with treatment longer than the maximum-labeled duration of 7 days. In clinical trials, the discontinuation rate due to drug-related adverse events was similar for FACTIVE tablets and comparators (2.2% versus 2.1%, respectively).

Gemifloxacin is contraindicated in patients with a history of hypersensitivity to gemifloxacin, fluoroquinolone antibiotic agents, or any of the product components. Patients receiving marketed fluoroquinolones have reported serious and occasionally fatal hypersensitivity and/or anaphylactic reactions, peripheral neuropathy, antibiotic-associated colitis and tendon ruptures. Gemifloxacin should be discontinued immediately at the first sign of any of these events.

Fluoroquinolones may prolong the QT interval in some patients. Gemifloxacin should be avoided in patients with a history of prolongation of the QTc interval, patients with uncorrected electrolyte disorders (hypokalemia or hypomagnesemia), and patients receiving Class IA or Class III antiarrhythmic agents. In clinical studies with gemifloxacin, CNS effects have been reported infrequently. As with other fluoroquinolones, gemifloxacin should be used with caution in patients with known or suspected CNS diseases. If CNS reactions occur, gemifloxacin should be discontinued and appropriate measures instituted.

No significant drug-drug interactions were seen with theophylline, digoxin, oral contraceptives, cimetidine, omeprazole, and warfarin, although patients receiving a fluoroquinolone concomitantly with warfarin should be monitored closely. Drug-drug interactions include probenicid, sucralfate, antacids containing aluminum or magnesium, iron, multivitamins containing metal cations, and didanosine. The safety and effectiveness of gemifloxacin in children, adolescents (less than 18 years of age), pregnant women, and lactating women have not been established. For complete safety and efficacy information, please see the full prescribing information available at www.factive.com.

Forward-Looking Statement

This news release may contain forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements represent our management's judgment regarding future events. Forward-looking statements typically are identified by use of terms such as "may," "will," "should," "plan," "expect," "intend," "anticipate," "estimate," and similar words, although some forward-looking statements are expressed differently. We do not plan to update these forward-looking statements. You should be aware that our actual results could differ materially from those contained in the forward-looking statements due to a number of risks affecting our business. These risks include, but are not limited to (i) our ability to successfully commercialize and market ANTARA or FACTIVE due to: the limitations on our resources and experience in the commercialization of products; lack of acceptance by physicians, patients and third party payors; unanticipated safety, product liability, efficacy, or other regulatory issues; delays in recruiting and training sales personnel; problems relating to manufacturing or supply; inadequate distribution of the products by wholesalers, pharmacies, hospitals and other customers; and competition from other products; (ii) our ability to integrate ANTARA into our business; (iii) whether we will be able to expand the indications for which FACTIVE is approved; (iv) the delay or inability to find sublicensing partners for FACTIVE or to negotiate favorable licensing terms; (v) the delay in or inability to obtain additional regulatory approvals of our products and product candidates due to negative, inconclusive or insufficient results in ongoing or future clinical trials, the FDA requiring additional information or data, delays in the progress of ongoing clinical trials, safety concerns arising with respect to our products or product candidates and disputes with the third parties from whom we license our products or product candidate; and (vi) delays by the FDA. Additional factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements are described under the heading "Risk Factors" in the Company's Quarterly Report on Form 10-Q for the quarter ending June 30, 2006 and in other filings that we may make with the Securities and Exchange Commission from time to time.