Now let's look at the two risks that keep me from buying Clovis at this time.

First, the clinical data on CO-101 are extremely limited. A small Phase 1 study in various late-stage cancers showed no significant tumor shrinkage; only a handful of treated patients reported stable disease. Clovis also stopped an earlier Phase 2 study poorly designed and started by Clavis. Interim results from this study showed some tumor shrinkage and stable disease, but only three patients had low hENT1 and none of those had a major response to drug. This paucity of data gives me pause.

My big worry is that Clovis doesn't seem to understand how CO-101 gets into the cell; if the drug can't get into the cell in hENT1 low patients, LEAP won't work. To engineer CO-101 from gemcitabine, Clavis added a lipid to one end of the molecule -- hardly revolutionary stuff. One study demonstrates that CO-101 inhibits cell growth in vitro in transporter-deficient cell lines. So far, the best thesis about CO-101's mechanism of transport is "passive diffusion." Again, this is a pretty thin branch on which to hang an investment.

By the time we get data on CO-101, Clovis will have roughly $70 million in cash. Even if we assign $40 million to the company's two interesting earlier-stage drug candidates, investors are valuing CO-101 at $420 million. That's a lot of downside, especially when no one fully understands how the drug gets to where it needs to be and there are virtually no clinical data to override that concern. I would keep Clovis on the radar screen for now.

Celgene

The key cancer asset behind Celgene's 2010 acquisition of Abraxis BioScience, Abraxane is a reformulation of the old anti-cancer drug paclitaxel with a human protein called albumin attached. Albumin facilitates transport of the drug into the tumor cell. Late last year, investigators published promising results from a phase I/II trial of the drug in pancreatic cancer. The study combined several doses of Abraxane with gemcitabine and sought to establish a maximum tolerated dose (MTD), the dose that best balances efficacy and side effects. Celgene reported an encouraging median survival of 12.2 months. Based on these data, Celgene initiated a large phase III trial of the drug in combination with gemcitabine. Results should be available around mid-year.

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