( Results Reported From Three NCI-Sponso...)Cytokinetics Reports Additional Clinical Trials Data for Ispinesib,Health

Results Reported From Three NCI-Sponsored Clinical Trials

SOUTH SAN FRANCISCO, CA June 28, 2007 - Cytokinetics, Incorporated (Nasdaq: CYTK) announced results from the analyses of three Phase II clinical trials of ispinesib administered as monotherapy, one in patients with hepatocellular cancer, one in patients with melanoma, and one in patients with hormone-refractory prostate cancer. Ispinesib is a novel small molecule inhibitor of kinesin spindle protein (KSP), a mitotic kinesin essential for proper cell division. Ispinesib has arisen from a broad strategic collaboration between Cytokinetics and GlaxoSmithKline (GSK) to discover, develop and commercialize novel small molecule therapeutics targeting human mitotic kinesins for applications in the treatment of cancer and other diseases. All three clinical trials were sponsored by the National Cancer Institute (NCI).

A Phase II clinical trial designed to evaluate the safety and efficacy of ispinesib in the treatment of patients with locally advanced, recurrent or metastatic hepatocellular cancer was recently completed. In Stage 1 of this two-stage clinical trial, 15 patients received ispinesib as monotherapy at 18 mg/m2 as a 1-hour intravenous infusion every 21 days. The trial s primary endpoint was objective response as determined using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. This trial was designed to require at least 1 confirmed partial or complete response out of 15 evaluable patients in Stage 1 in order to proceed to Stage 2. The best overall response was stable disease seen in 7 of the 15 patients treated. In this clinical trial, ispinesib did not satisfy the criteria for advancement to the second stage and therefore recruitment to Stage 2 was not opened. The toxicity profile was consistent with other previously reported Phase II clinical trials of ispinesib. A manuscript is being prepared.

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