Pfizer's Fungus Failure

Top-line results from a phase 3 trial showed that Eraxis plus Vfend was no better than Vfend alone at treating invasive aspergillosis, a life-threatening fungal infection. Both drugs are owned by Pfizer (NYSE: PFE  ) , which ran the study.

This is one of those no-lose situations for Pfizer. Eraxis is already on the market to fight other types of infections. If the trial had showed a statistically significant reduction in mortality, Pfizer could have gotten Eraxis approved for the added indication.

The oral version of Vfend, which is approved to treat invasive aspergillosis, already has generic competition from Mylan (Nasdaq: MYL  ) , and Novartis (NYSE: NVS  ) has a tentative approval from the Food and Drug Administration for an injectable form of the drug.

Going generic wouldn't have affected sales of Eraxis. Adding on to a generic, rather than running a head-to-head trial, is a good strategy because then you don't actually have to compete with the cheap medication. Many diabetes drugs, including Merck's (NYSE: MRK  ) Januvia and Bristol-Myers Squibb (NYSE: BMY  ) and AstraZeneca's (NYSE: AZN  ) Onglyza, have been tested in combination with metformin, a generic that many diabetics start on. Both drugs are even available as combination pills that contain the brand-name drug plus metformin.

While this was a no-lose situation for Pfizer, it was unfortunately a no-win result. There was a trend toward a reduction in mortality, but it wasn't statistically significant. You could argue that if Pfizer had enrolled more patients in the trial, the same difference might have been statistically significant. But invasive aspergillosis is fairly rare -- it crops up mostly in patients with weakened immune systems -- and it took Pfizer two and a half years to enroll the study, so we should probably let the company off the hook.

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