CombinatoRx Presents Preclinical Data on CRx-401, a Novel Insulin Sensitizer with Anti-Diabetic Activity

-- Data presented at American Diabetes Association Meeting --

CombinatoRx, Incorporated (NASDAQ: CRXX) today announced thepresentation of preclinical data on CRx-401, a novel insulinsensitizer with anti-diabetic activity, at the 66th ScientificSessions of the American Diabetes Association, June 9-13, 2006 inWashington, D.C. The data demonstrate that CRx-401, a novelcombination drug candidate in preclinical development for diabetes,acts synergistically to increase glucose uptake in vitro ininsulin-sensitive cell types. The anti-diabetic activity of CRx-401translates in vivo in a rat model of insulin resistance, significantlyreducing fasting blood glucose and homeostasis modelassessment-insulin resistance (HOMA-IR) scores, while the singleagents do not improve these measures. CRx-401 also reduced body weightgain as compared both to thiazolidinedione-treated and toplacebo-treated animals. Thiazolidinedione (TZD) is a class of drugsfor the treatment of type 2 diabetes.

In a poster entitled "CRx-401 a Novel Syncretic Insulin Sensitizerwith Synergistic Anti-diabetic Activity," Finelli, et.al., presentedpreclinical data on rats that were fed a high-fat diet, in whichCRx-401 reduced mean fasting blood glucose levels by 39% and increasedinsulin sensitivity, as measured by a 74% reduction in mean HOMA-IRscore. Treatment with an approved agent of the TZD class reduced meanblood glucose levels by 21% and resulted in a 27% reduction in meanHOMA-IR score in this study. Of note, weight gain was less in animalstreated with CRx-401 (28%) than with those treated with TZDs (48%) orwith placebo (47%). No adverse drug-drug interactions or overlappingtoxicities were observed in animal efficacy studies of CRx-401 or itscomponents.

"We are encouraged to see that CRx-401 shows synergisticanti-diabetic activity in vivo. We are currently investigating themechanism of action and the potential benefits of CRx-401 treatment oninsulin sensitivity, weight gain and edema in additional preclinicalmodels of insulin resistance," commented Curtis T. Keith, Ph.D.,Senior Vice President, Research of CombinatoRx. "These data furtherdemonstrate the capability of the CombinatoRx cHTS discoverytechnology to rapidly identify novel synergistic combinations inserious diseases such as diabetes."

About CRx-401

CRx-401 is a novel orally available syncretic drug candidate inpreclinical development for diabetes. A syncretic drug comprises twocompounds that are designed to act synergistically through multiplepathways to provide a novel therapeutic effect which neither componentalone can achieve. CRx-401 contains a low dose of diflunisal andbezafibrate, neither of which is indicated for the treatment ofdiabetes on its own, but which have been shown in preclinical studiesto act synergistically to increase insulin sensitivity and lowerplasma glucose. CRx-401 was discovered using the CombinatoRxcombination High Throughput Screening (cHTS(TM)) technology and wouldbe developed in a unique formulation for the treatment of metabolicdisease such as diabetes.

About Diabetes and Type 2 Diabetes

Diabetes is a disease in which the body does not produce orproperly use insulin. Insulin is a hormone that is needed to convertsugar, starches and other food into energy. According to the AmericanDiabetes Association (ADA), there are 20.8 million children and adultsin the United States, or 7% of the population, who have diabetes.While an estimated 14.6 million have been diagnosed with diabetes,another 6.2 million people (nearly one-third) are unaware that theyhave the disease.

The most common form of diabetes is type 2 diabetes, which resultsfrom insulin resistance (in which the body fails to properly useinsulin), combined with relative insulin deficiency. Most Americanswho are diagnosed with diabetes have type 2 diabetes. Complications oftype 2 diabetes can include cardiovascular disease, blindness, andnerve and kidney damage.

About CombinatoRx

CombinatoRx, Incorporated is a biopharmaceutical company focusedon developing new medicines built from synergistic combinations ofapproved drugs, designed to attack disease on multiple fronts.CombinatoRx applies its proprietary combination drug discoverytechnology to identify new combination product candidates in a numberof disease areas, including immuno-inflammatory disease, oncology,metabolic disease, neurodegenerative disease, and infectious disease.We are currently developing a portfolio of 6 product candidatestargeting multiple diseases which were discovered by applying ourproprietary screening technology. For further information, pleasevisit the CombinatoRx website at www.combinatorx.com.

Forward-Looking Statement

This press release contains forward-looking statements within themeaning of the Private Securities Litigation Reform Act of 1995concerning the preclinical study results for CRx-401, its plans forfurther research and development of the Company's CRx-401 researchprogram, its plans with respect to the research and development of theother product candidates in its portfolio and its drug discoverytechnology. These forward-looking statements about the futuredevelopment of CRx-401 and future expectations, plans and prospects ofCombinatoRx involve significant risks, uncertainties assumptions,including risks related to the preclinical stage of development ofCRx-401, including the ability of CRx-401 to succeed in additionalpreclinical studies, the ability of CombinatoRx to design and executefuture preclinical and clinical studies of CRx-401, the ability ofCombinatoRx to initiate and successfully complete clinical trials ofits product candidates, potential difficulty and delays in obtainingregulatory approval for the sale and marketing of its productcandidates, the unproven nature of the Company's drug discoverytechnology, the Company's ability to obtain additional funding for itsresearch and development and those other risks that can be found inthe "Risk Factors" section of the CombinatoRx Annual Report Form 10-Kon file with the Securities and Exchange Commission and the otherreports that CombinatoRx periodically files with the Securities andExchange Commission. Actual results may differ materially from thoseCombinatoRx projects.

In addition, the forward-looking statements included in this pressrelease represent the Company's views as of the date of this release.CombinatoRx does not undertake to update any of these forward-lookingstatements to reflect a change in its views or events or circumstancesthat occur after the date of this release.

(c) 2006 CombinatoRx, Incorporated. All rights reserved.