For all you investors out there, remember there are three steps to getting a drug on the market in the U.S.: getting subjects enrolled in the clinical trial, meeting the trial's endpoints, and getting approved by the Food and Drug Administration. So don't jump in too early.

Amgen (NASDAQ:AMGN) and Takeda Pharmaceutical are stuck on step one.

The trial was testing motesanib in combination with generic versions of Bristol-Myers Squibb's (NYSE:BMY) Taxol and Paraplatin in non-small cell lung cancer (NSCLC) patients. A data monitoring board suspended enrollment in the phase 3 trial because of higher early mortality rates in patients getting motesanib versus those getting placebo.

The monitoring board is letting patients with non-squamous NSCLC already enrolled in the study continue, but it recommended patients with squamous NSCLC discontinue therapy because of a higher incidence of hemoptysis -- coughing or spitting up blood.

That's not particularly surprising. Genentech's (NYSE:DNA) Avastin, an anti-VEGF therapy like motesanib, also shows high levels of hemoptysis in patients with squamous NSCLC. And early this year, Onyx Pharmaceuticals (NASDAQ:ONXX) and Bayer saw higher mortality in squamous NSCLC patients taking Nexavar, which also attacks VEGF, but through a different mechanism.

The safety board will review more data in three months, but things certainly aren't looking up for Amgen and Takeda at the moment. The duo is also testing motesanib in breast cancer, but don't use the above to predict the success rate for that. There are plenty of examples of drugs that work for one cancer type, but not others. For instance, Nexavar is used for liver and kidney cancer while Avastin is approved for colon cancer and non-squamous NSCLC.

Lung cancer is a hard disease to fight -- just ask AstraZeneca (NYSE:AZN), which also recently reported disappointing lung cancer trial results. Investors shouldn't put too much value on pipeline drugs to treat lung cancer until they've proven themselves in phase 3 trials. Better to be conservative and get a pleasant surprise if the drug actually works.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.