Semafore Pharmaceuticals, Inc.'s PI3 Kinase Inhibitor SF1126 is Active Against Tumor and Tumor Cells and Synergizes with Standard Chemotherapy Agents

SAN FRANCISCO, Oct. 26 /PRNewswire/ -- Semafore Pharmaceuticals Inc. announced today on the occasion of a poster presentation at the 2007 AACR-NCI- EORTC International Conference in San Francisco that its integrin-targeted PI3 kinase inhibitor, SF1126, showed synergistic effects with certain standard chemotherapy agents in vitro and in vivo (poster C207).

In vitro data showed significant (p<0.001) synergistic growth inhibition of prostate cancer cells with combinations of docetaxel and SF1126, as well as synergistic growth inhibition of brain cancer cells with combinations of doxorubicin and SF1126. In addition, SF1126 and rapamycin showed excellent growth inhibition synergies across all prostate, renal and non-small cell lung cancer cell lines. Simultaneous dosing of SF1126 with docetaxel in a prostate xenograft model exhibited slightly improved tumor response time versus administering SF1126 prior to docetaxel administration. In this same xenograft model, using very large tumors, it was shown that SF1126 in combination with docetaxel gave significantly greater tumor regression than did docetaxel alone (p<0.05). SF1126 as a single agent showed significant tumor growth inhibition relative to the control group (73% inhibition, p<0.01) in this model as well.

“These data support that our lead compound, SF1126, is active as a single agent and in synergy with a growing list of standard chemotherapy agents,” said Edward Jacobs, Semafore’s president and chief executive officer. “This provides us with a pathway to clinical development in addition to our current phase I clinical trial in patients with solid tumors. We expect to complete our phase I clinical trial in the second quarter of 2008 and then evaluate SF1126 in additional trials, both as a single and combined therapy.”

About SF1126

SF1126 is a small molecule conjugate containing a pan-PI3K inhibitor that selectively inhibits all PI3K class IA isoforms and other key members of the PI3K superfamily, including DNA-PK and mTOR. A major factor in tumor resistance to approved chemotherapy agents is thought to be the activation of the PI3K/PTEN pathway. As a result, it is thought that inhibiting this pathway, via SF1126, could cause the resetting of sensitivity to approved agents and exhibit synergistic anticancer effects.

About Semafore

Semafore is a clinical stage drug discovery and development company focused on small molecule modulators of the PI3 kinase and PTEN cell signaling pathway, a promising target pathway for multiple disorders, including the company’s focus--cancer. Semafore is one of the first biopharmaceutical companies to focus on both PI3K and PENN and has successfully discovered and is developing a portfolio of drug candidates addressing these targets. For more information see the company’s website at www.semaforepharma.com.

david.schull@russopartnersllc.comtimothy.engel@russopartnersllc.com

CONTACT: David Schull, david.schull@russopartnersllc.com, or Timothy
Engel, timothy.engel@russopartnersllc.com, both of Russo Partners, LLC,
+1-212-845-4271

Web site: http://www.semaforepharma.com/

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