Ahh, the joys of biotech. In what other industry is it possible to wake up and see the value of your stock triple from what it was the night before?

The latest beneficiary, Human Genome Sciences (NASDAQ:HGSI), is up more than 220% today on word that Benlysta, a systemic lupus erythematosus (SLE) drug it's developing with GlaxoSmithKline (NYSE:GSK), works. At the higher dose, 57.6% of patients adding Benlysta to the standard care had an improvement in their symptoms, compared with 43.6% who got placebo plus the standard care.

Much like Vanda Pharmaceuticals (NASDAQ:VNDA) and Dendreon (NASDAQ:DNDN) earlier this year, few people figured that Human Genome Sciences would pass the binary event. A drug hasn't been approved specifically for lupus in decades -- not that companies haven't tried: Biogen Idec (NASDAQ:BIIB), Teva Pharmaceuticals (NASDAQ:TEVA), and Biomarin Pharmaceuticals (NASDAQ:BMRN) all have drugs in the lupus graveyard.

It's easy to beat yourself up over not getting in on Human Genome Sciences' run-up, but you really shouldn't. Biotech is a game of percentages where neither success nor failure is guaranteed and the return has to justify the estimated chance of success. When it comes to diseases like lupus, where it's difficult to determine the chance of success, I think it's perfectly reasonable to spend your time looking for diseases that are easier to understand.

Human Genome Sciences isn't out of the woods yet; Benlysta still has to pass its second phase 3 trial, the results of which are expected in November. The risk of failure is significantly lower because the trial design is essentially the same. Just don't expect another triple if the second trial is a success.

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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.