Lowered guidance is never a welcome sight, but investors shouldn't treat all revised estimates equally. Consider the two possible choices:

  • Lower than hoped for revenue because customers are buying less. Examples: FedEx (NYSE:FDX), Monsanto (NYSE:MON), Tenet Healthcare (NYSE:THC), Carnival (NYSE:CCL). The list could go on and on.
  • Lowered guidance because a company can't make enough to keep up with demand. Example: Genzyme (NASDAQ:GENZ).

Genzyme isn't in the ideal situation; a virus infected the production of one of its drugs and shut down an entire plant, which will lead to a shortage of two drugs that treat rare genetic diseases -- Cerezyme and Fabrazyme.

The shutdown is going to cost Genzyme some serious dough. Revenue guidance for the year is being slashed from a range of $5.15 billion to $5.35 billion to a range of $4.6 billion to $5.0 billion. EPS guidance is down to $1.74 to $2.29 per share from an earlier estimate of $3.02 per share.

The good news is that production will restart soon and drugs should be available by the end of the year. Since both drugs treat rare disease, there's no real danger of losing the patients to the competition. Shire Pharmaceuticals (NASDAQ:SHPGY) and Protalix BioTherapeutics (NYSE:PLX) are both working on drugs that would compete with Cerezyme, but, since they're not on the market yet, they're not an immediate threat if Genzyme can get this cleared up quickly.

This isn't the first time Genzyme hasn't been able to meet demand for its drugs. Earlier this year the Food and Drug Administration delayed Genzyme's application to make its pompe disorder drug, Myozyme, at a larger scale, which led to shortages.

Bears will argue that this is a bad trend, but it just shows that the risk of investing in biotech companies doesn't end after the drugs are approved. Genzyme should be able to get production back on track; demand will still be there when it does.

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