Close, but no cigar. That's pretty much been the story of Onyx Pharmaceuticals (Nasdaq: ONXX) and Bayer's (OTC: BAYRY.PK) Nexavar in lung cancer.

And it's been going on for a while.

Back in 2008, Nexavar failed to show an effect in lung cancer in a trial dubbed ESCAPE (Evaluation of Sorafenib, Carboplatin, And Paclitaxel Efficacy in NSCLC). Sorafenib is the generic name for Nexavar, and carboplatin and paclitaxel are generic versions of drugs from Bristol-Myers Squibb (NYSE: BMY).

But a subset of patients with squamous cell cancer, a subtype of lung cancer, fared worse, giving Onyx and Bayer hope that excluding those patients could help prove the drug works in lung cancer patients.

The companies tested the drug in another clinical trial called NExUS (NSCLC research Experience Utilizing Sorafenib). But when Nexavar was added to a chemotherapy regimen of Eli Lilly's (NYSE: LLY) Gemzar and a generic called cisplatin, patients didn't fare any better compared with Gemzar and cisplatin alone in first-line lung cancer patients.

But again there were hints the drug was working. While the patients didn't survive longer, the triple combination did extend progression-free survival, a measure of how long it takes until the tumor begins growing again.

That was just enough of a signal to continue a trial in patients that had failed other treatments. On a mission to prove the drug works in lung cancer -- and clearly getting desperate with the acronyms -- the duo continued with MISSION (Monotherapy admInistration of Sorafenib in patientS wIth nOn-small cell luNg cancer), which tested Nexavar as a monotherapy in patients that had failed other treatments.

The results? More of the same. Nexavar failed to improve overall survival but improved progression-free survival. Clearly, Nexavar is doing something to the tumors, but either the toxicity of the drug is counteracting that, or stopping the tumor from growing isn't doing anything to improve survival. Progression-free survival and overall survival are often correlated, but not always. AstraZeneca (NYSE: AZN) had a similar experience with its lung cancer drug Iressa, which eventually led to its getting pulled off the U.S. market.

I can't really fault Onyx and Bayer for pushing it this far. Lung cancer is a big market and would be an easy way to increase sales beyond liver and kidney cancer. But after three failed phase 3 trials, we can only hope that the quest is over, as it appears the NExUS between ESCAPE and MISSION is failure.

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