Celtic Pharma Announces Preclinical Findings that XERECEPT(R) Potentiates Significantly the Tumor Inhibition Activity of Avastin(R)

NEW YORK, LONDON and BERMUDA, April 19, 2010 /PRNewswire/ -- Celtic Pharmaceutical Holdings L.P. ("Celtic Pharma") today reported at the AACR 101st Annual Meeting 2010 in Washington, DC the results from several preclinical studies of XERECEPT(R) in established models for breast, colon and brain tumors. These animal studies were conducted at Duke University and the Piedmont Research Center using solid human tumors including breast and colon xenografts as well as both pediatric and adult human brain tumor xenografts. All of these models demonstrated statistically significant tumor regression and prolongation of survival following treatment with XERECEPT(R) in combination with Avastin(R), compared to Avastin(R) alone. In the human breast model both Avastin(R) and Xerecept(R) by themselves produced similar antitumor effects, however, when Avastin(R) was combined with Xerecept(R), antitumor effect was significantly increased (p<0.001). The enhanced combination effect was statistically different (p<0.03) than either result associated with the monotherapies. In the human colon xenograft model, Xerecept was not active alone against this tumor model, while Avastin(R) produced a significant tumor growth delay compared to the vehicle-treated control. However, the combination therapy of Avastin(R) plus Xerecept(R) significantly increased the overall survival of animals when compared to treatment with vehicle (p<0.001) or bevacizumab alone (p<0.01). In the High Grade Pediatric GBM model, Xerecept(R) had activity by itself, and the combination of Xerecept(R) with bevacizumab was significantly better than bevacizumab or Xerecept(R) alone. These preclinical findings demonstrate that XERECEPT(R) has the ability to potentiate or provide a synergistic enhancement of the antitumor effects of Avastin(R), in these various models.

"We have been seeing anecdotal observations from the Phase III trials of Xerecept in brain tumor patients that this molecule may be doing more for some of these patients than just controlling edema. Interestingly, we have 13 brain tumor patients still on daily Xerecept treatment from the 501 Phase III open label study, with an average of 38 months (range 25 to 53 months) on drug to date" commented Stephen Evans-Freke, Managing General Partner of Celtic Pharma. "These new preclinical findings of synergistic activity of Xerecept in combination with Avastin(R) in major tumor types may indicate a broader role for this molecule than has been understood up to now".

"From both a medical point of view and a commercial point of view, this information could have profound implications and certainly merits further investigation," said John Mayo, Managing General Partner of Celtic Pharma.

"We are happy to have the opportunity to work with Celtic on this potential new therapeutic combination for major solid tumor patient populations," commented Beth Hollister, Corporate Vice President, Charles River Discovery and Imaging Services and Founder of Piedmont Research Center. "We look forward to continuing to add to the scientific knowledge base for this treatment as preparations are made for expanded clinical trials."

XERECEPT(R) is an investigational new drug under development as a steroid-sparing alternative to dexamethasone for patients with primary and metastatic brain tumors. Dexamethasone is currently the standard treatment for peritumoral brain edema, but is associated with debilitating side effects including diabetes mellitus, hypertension, muscle weakness, bone loss, impaired wound healing and opportunistic infections.

About Celtic Pharmaceutical Holdings L.P.

Celtic Pharmaceutical Holdings L.P. (Celtic Pharma) is a global private equity investment firm focused on the biotechnology and pharmaceutical industries. Celtic Pharma was founded by Stephen Evans-Freke and John Mayo, CBE and is based in Bermuda, with offices in New York and London. Celtic Pharma acquires and invests in late stage pharmaceutical programs and manages these programs through their development to regulatory approval. Celtic Pharma's aim is to bridge the gap between the established pharmaceutical companies' new product pipeline crisis and the biotech industry's capital drought. For further information, please visit Celtic Pharma's website at http://www.celticpharma.com.

Forward-Looking Statements

Certain statements in this press release that are not historical facts, including statements that are preceded by, or followed by, or that include words such as "may," "expect," "anticipate," "believe," or "plan," or similar statements, are forward-looking statements that involve risks and uncertainties, including risks relating to the results of the clinical trials for XERECEPT(R) and the ability of Celtic Pharma to obtain regulatory approval for XERECEPT(R). Actual results may differ materially from those projected. These forward-looking statements represent our judgment as of the date of the release. We disclaim, however, any intent to update these forward-looking statements.

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SOURCE Celtic Pharmaceutical Holdings L.P.