When a company issues a press release about the final data from a phase 2 clinical trial, investors want to see the words "phase 3" somewhere in it -- hopefully preceded by "will initiate." Alas, Cytokinetics' (NASDAQ:CYTK) latest news lacked those words.

The multicenter phase 2 clinical trial, sponsored by partner GlaxoSmithKline (NYSE:GSK), was testing Cytokinetics' ispinesib compound in patients with locally advanced or metastatic breast cancer who had failed earlier treatments. Early results presented in late 2005 looked promising, allowing the trial to progress from stage 1 to stage 2.

In the second portion of the trial, only four of 45 patients showed a partial response to the drug. Patients who have failed earlier treatments have a poor prognosis, so in some ways, any progress is good. But responses from less than 10% of patients aren't good enough to continue into phase 3 trials. Instead, the company announced that it would initiate a phase 1/2 clinical trial for first-line treatment of patients with advanced or metastatic breast cancer. Ispinesib may show better results in these easier-to-treat patients.

The results got worse later in the day, as Cytokinetics announced failures of another three phase 2 trials testing ispinesib for treating hepatocellular cancer, melanoma, and hormone-refractory prostate cancer. In all three trials, ispinesib didn't show a strong enough response to merit further development for these cancers; don't hold your breath for any phase 3 trials here.

Ispinesib was developed in a joint venture between Cytokinetics and Glaxo, seeking small, kinesin-inhibiting molecules to be used for cancer treatment. (Kinesins transport large molecules within cells, aiding cell division. Inhibiting certain kinesins in cancer cells may help stop those cells from dividing, halting tumor growth.)

A second molecule from the six-year-old venture, SB-743921, is in phase 1/2 clinical trials for non-Hodgkin's lymphoma. While it inhibits the same protein as ispinesib, it is structurally distinct, and could work better.

Cytokinetics has additional research focused on finding drugs that activate cardiac myosin. Its lead compound, CK-1827452, entered phase 2 clinical trials designed to evaluate its potential in treating heart failure. Amgen (NASDAQ:AMGN) has an option for joint development and commercialization of the compound, should it show promise in future clinical trials.

With no drugs in phase 3 clinical trials, it's amazing that the company commands a $300 million market cap. Cytokinetics' biggest current advantage is its $170 million in the bank -- which partially explains the inflated market cap. At a burn rate of $47 million a year, it has a few years to shepherd at least one of its compounds through a successful phase 3 trial. Until then, for this Fool, it's nothing more than a stock to keep an eye on.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. He blogs about small biotech companies at babybiotechs.com. GlaxoSmithKline is an Income Investor recommendation. The Fool has a disclosure policy.