The Medicines Company Completes Enrollment of 13,800-Patient ACUITY Trial of Angiomax(R) (bivalirudin); ACUITY One of the Largest Global Clinical Trials Ever Conducted to Evaluate Anticoagulants Used In ACS Patients.

PARSIPPANY, N.J. -- The Medicines Company (NASDAQ: MDCO) today announced completion of patient enrollment in the 13,800 patient global Phase III ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) trial. This randomized clinical trial is evaluating the direct thrombin inhibitor Angiomax(R) (bivalirudin) replacing heparins (unfractionated heparin or enoxaparin) in patients with acute coronary syndromes (ACS) presenting to the emergency department. ACUITY is being conducted at 450 clinical trial sites in 17 countries worldwide. In Europe, where more than 4,000 patients were enrolled, Nycomed is co-sponsoring the trial.

"The enrollment of over 13,800 patients with acute coronary syndromes into the ACUITY trial in just over two years is an incredible achievement and a testament to the importance of improving the otherwise poor prognosis in these high-risk patients," said ACUITY's Principal Investigator, Gregg W. Stone, MD, Professor of Medicine and Director of Cardiovascular Research and Education at Columbia University Medical Center's Center for Interventional Vascular Therapy and Vice-Chairman of the Cardiovascular Research Foundation. "We are hopeful that the results of this landmark trial will establish a new standard of care for patients with unstable coronary artery disease."

The first announcement of ACUITY results is expected at the American College of Cardiology Annual Scientific Session in March 2006. Results are also expected to be published in a leading peer-reviewed journal.

ACUITY is evaluating the use of Angiomax, replacing the heparins, starting in the emergency department or critical care unit and continued through the cardiac catheterization laboratory. The control arm of ACUITY is comprised of patients treated with the heparins combined with glycoprotein (GP IIb/IIIa) inhibitors, which are intravenous antiplatelet agents. In the other two arms of the trial, Angiomax is being evaluated alone and with the use of GP IIb/IIIa inhibitors.

"Previous data show there is a need for a safer alternative to heparin for patients with ACS," said John Kelley, President and Chief Operating Officer of The Medicines Company. "Because we have seen favorable outcomes in patients with high risk characteristics in REPLACE-2, we anticipate that the ACUITY trial will support the use of Angiomax in ACS, whether or not patients undergo PCI, and will provide patients with a safe and effective treatment option to unfractionated heparin or enoxaparin."

In the United States each year, 1.8 million patients are hospitalized for ACS. Ischemic heart disease patients are subject to chest pain that results from a range of conditions, from unstable angina to acute myocardial infarction. The severe onset of these cardiac conditions is collectively referred to as ACS.

Many ACS patients enter the hospital by way of the emergency department before they are admitted to the cardiac catheterization laboratory or operating room for further interventional or surgical treatment. Treatment with the anticoagulant drugs known as heparins (unfractionated heparin or enoxaparin, a low molecular weight heparin) is often started while patients are in the emergency department.

About Angiomax

Angiomax(R) (bivalirudin) is currently approved in the U.S. and the European Union, as well as several other countries. In Europe, the product is marketed by Nycomed and Ferrer Grupo as Angiox(R). Angiomax is a direct thrombin inhibitor with a naturally reversible mechanism of action. In clinical trials, Angiomax has demonstrated reductions in both ischemic and bleeding complications compared to heparin as the foundation anticoagulant in the contemporary catheterization lab setting. These reductions in ischemic and bleeding complications remain evident even in high-risk patients.

In the U.S., Angiomax is indicated for use as an anticoagulant in patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA) and with provisional GP IIb/IIIa inhibition in patients undergoing percutaneous coronary intervention (PCI). Angiomax is also indicated in patients with, or at risk of, heparin-induced thrombocytopenia and thrombosis syndrome (HIT/HITTS) undergoing PCI. Angiomax is intended for use with aspirin. The most common adverse events for Angiomax in clinical trials comparing Angiomax and heparin were back pain, pain, nausea, headache, and hypotension. The incidence of these adverse events was comparable in both the Angiomax and heparin groups in these trials. An unexplained fall in blood pressure or hematocrit, or any unexplained symptom, should lead to serious consideration of a hemorrhagic event and cessation of Angiomax administration. Angiomax is contraindicated in patients with active major bleeding or hypersensitivity to Angiomax or its components. Please see full prescribing information available at http://www.angiomax.com.

About The Medicines Company

The Medicines Company meets the demands of the world's most advanced medical practitioners by developing products that improve acute hospital care. The Company markets Angiomax(R) (bivalirudin), an anti-clotting therapy approved in the U.S. and other countries for use in patients undergoing coronary angioplasty, a procedure to clear restricted blood flow in arteries around the heart. The Medicines Company creates value using its range of clinical and commercial skills to develop products acquired from leading life science innovators. The Company's website is http://www.themedicinescompany.com.

Statements contained in this press release about The Medicines Company and Angiomax that are not purely historical, and all other statements that are not purely historical, may be deemed to be forward-looking statements for purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. Without limiting the foregoing, the words "believes," "anticipates" and "expects" and similar expressions are intended to identify forward-looking statements. These forward-looking statements involve known and unknown risks and uncertainties that may cause the Company's actual results, levels of activity, performance or achievements to be materially different from those expressed or implied by these forward-looking statements. Important factors that may cause or contribute to such differences include the extent of the commercial success of Angiomax, physicians' acceptance of Angiomax clinical trial results, whether the Company's products will advance in the clinical trials process, whether clinical trial results will warrant submission of applications for regulatory approval, whether the Company will be able to obtain regulatory approval for additional indications of Angiomax and such other factors as are set forth in the risk factors detailed from time to time in the Company's periodic reports and registration statements filed with the Securities and Exchange Commission including, without limitation, the risk factors detailed in the Company's Quarterly Report on Form 10-Q filed on November 8, 2005, which are incorporated herein by reference. The Company specifically disclaims any obligation to update these forward-looking statements.