Curis Publishes Preclinical Data for Heat Shock Protein 90 Molecule CUDC-305 in Clinical Cancer Research.

- CUDC-305, lead development candidate from novel small molecule chemical class of Heat Shock Protein (HSP) 90 inhibitors, demonstrates potent anti-cancer activity in pre-clinical cancer models and possesses favorable pharmacological properties -

CAMBRIDGE, Mass. -- Curis, Inc. (NASDAQ: CRIS), a drug development company focused on developing proprietary targeted medicines for cancer treatment, today announced that preclinical data related to CUDC-305, the company's Heat Shock Protein (HSP) 90 inhibitor, was published online this week in Clinical Cancer Research. The paper, entitled "CUDC-305, a novel synthetic HSP90 inhibitor with unique pharmacological properties for cancer therapy," will also be published in the print version of this journal shortly.

The publication reports that, in addition to potent antitumor efficacy against a broad range of cancers in preclinical tumor models as both a single agent and in combination, CUDC-305 exhibits promising pharmacological features in several areas, including high oral bioavailability, tumor selectivity, blood-brain barrier penetration, and extended retention of the compound in tumor tissue relative to normal tissue.

"We believe that the data published in this Clinical Cancer Research journal supports our belief that CUDC-305 is potentially a best-in-class HSP90 inhibitor and I would like to acknowledge the efforts of our research and development staff in the discovery and development of this compound," stated Dan Passeri, President and Chief Executive Officer. "HSP90 inhibition represents a promising strategy for cancer therapy since this inhibition concurrently blocks multiple targets or pathways. This approach is consistent with Curis' overall strategy of developing drugs that seek to disrupt cancer networks. As we prepare for a planned mid-2009 IND filing, we continue to be optimistic that we will enter into a meaningful collaboration for this asset in 2009 for its future clinical development."

The publication includes compelling in vivo data from a variety of preclinical cancer models. For example, complete tumor regression was observed in a model of acute myeloid leukemia (AML), a hematological (blood) malignancy. In addition, administration of CUDC-305 as a single agent resulted in tumor stasis or regression in multiple tumor models, including in a non-small cell lung cancer cell line that becomes resistant to EGFR inhibition as well as in triple negative breast cancer and colorectal cancer models. The compound also effectively penetrated the blood brain barrier and prolonged animal survival in an orthotopic glioblastoma tumor model. In addition to efficacy obtained via dosing as a single agent, CUDC-305 administered in combination with standard of care cytotoxic agents showed enhanced efficacy in breast and colorectal cancer models.

The publication further demonstrates that CUDC-305 is a novel HSP90 inhibitor with binding potency similar to other synthetic HSP90 inhibitors in development. CUDC-305 also is potent in antiproliferation assays against 40 cancer cell lines covering solid as well as hematological tumor types. Mechanistically, as demonstrated through in vitro and in vivo studies, CUDC-305 is able to simultaneously downregulate multiple client proteins, including receptor tyrosine kinase and downstream signaling molecules of multiple signaling pathways essential to cancer cell proliferation and survival.

Data reported in the publication also show that CUDC-305 is highly oral bioavailable (96% in mice) and that the compound has extended retention in tumor tissue, including a half life of over 20 hours, which in turn resulted in durable pharmacodynamic effects up to 48 hours after a single dose of the compound. The compound is cleared quickly in normal tissues, with a half life of 3-7 hours.

About HSP90

HSP90 is a member of a class of proteins called molecular chaperones that play a fundamental role in the folding, stabilization and degradation of other cellular proteins, or clients, under normal or stressful conditions. HSP90, in particular, has become an attractive therapeutic target for the treatment of cancer because a majority of its client proteins are involved in cellular signaling transduction and have been identified as potential contributors to various aspects of cancer cell growth and survival. Inhibitors of HSP90 activity may be of therapeutic value if they can prevent HSP90 proteins from protecting the particular client proteins involved in cancer and allow them to be degraded, thereby inducing cancer cell death.

About Curis, Inc.

Curis is a drug development company that is committed to leveraging its innovative signaling pathway drug technologies to seek to create new medicines, primarily for cancer. In expanding its drug development efforts in the field of cancer through its targeted cancer drug development platform, Curis is building upon its previous experiences in targeting signaling pathways for the development of next generation targeted cancer therapies. For more information, visit Curis' website at www.curis.com.

Cautionary Statement: This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including without limitation: statements regarding management's expectation that CUDC-305 may be a best-in-class HSP90 inhibitor and that Curis is preparing for an IND filing in mid-2009 and is also seeking to enter into a collaboration for this compound in 2009. Forward-looking statements used in this press release may contain the words "believes",

"expects", "anticipates", "plans", "seeks", "estimates", "will", "may" or similar expressions. These forward-looking statements are not guarantees of future performance and involve risks, uncertainties, assumptions and other factors that may cause the actual results to be materially different from those indicated by such forward-looking statements including, among other things:

* Curis may experience adverse results, delays and/or failures in its internal drug development programs.

* Curis' collaborator, Genentech, may experience adverse results, delays and/or failures in the Hedgehog pathway inhibitor program currently under clinical development.

* Curis may experience difficulties or delays in obtaining or maintaining required regulatory approvals for products under development both internally and through its collaboration with Genentech.

* Curis may not be able to obtain or maintain the intellectual property protection necessary for the development and commercialization of drug candidates based on its technologies.

* Curis may not be able to obtain the additional funding required to conduct research and development of its drug candidates.

* Curis may experience unplanned cash requirements and expenditures which, among other things, could shorten the estimated period in which Curis will have cash to fund its operations and which could also adversely affect Curis' estimated operating expenses for 2009 and beyond.

* Curis faces risks relating to its ability to enter into and maintain planned collaborations for development candidates under its targeted cancer programs, its ability to maintain its current collaborations with Genentech and the risk that any such collaborators will not perform adequately.

* Curis also faces other risk factors identified in its most recent Quarterly Report on Form 10-Q and other filings that it periodically makes with the Securities and Exchange Commission.

In addition, any forward-looking statements represent the views only as of today and should not be relied upon as representing Curis' views as of any subsequent date. Curis disclaims any intention or obligation to update any of the forward-looking statements after the date of this press release whether as a result of new information, future events or otherwise.