There hasn't been a new drug to treat lupus since the Eisenhower administration, and unfortunately, patients will have to wait at least a little while longer.

Aspreva Pharmaceuticals (NASDAQ:ASPV) and its partner Roche announced Monday that they wouldn't file a marketing application with the Food and Drug Administration to use CellCept as an induction therapy for lupus.

In June, the company announced preliminary results from its phase 3 trial testing CellCept in patients with lupus. The oral drug failed to meet its primary endpoint because it didn't perform any better than an already-approved treatment of intravenous cyclophosphamide (IVC) in the induction phase of the trial.

A maintenance phase of the trial is still underway, and the drug might prove to be effective in that phase. But investors will have to wait a while before they get to see the results of the second half of the trial: The maintenance phase will last three years, or until a predetermined number of patients has dropped out of the trial.

CellCept is approved to prevent organ transplant rejection in the United States, the European Union, and other countries. Because it's effective in suppressing the immune system from attacking other people's organs, it seemed likely that it would work for patients suffering from lupus, where the patient's immune system attacks its own organs.

If the drug is ever approved, it would have to compete with a whole host of drugs currently in trials to treat lupus, including Lymphostat-B, from Human Genome Sciences (NASDAQ:HGSI) and GlaxoSmithKline (NYSE:GSK), as well as Bristol-Myers Squibb's (NYSE:BMY) Orencia and Genentech's (NYSE:DNA) and Biogen Idec's (NASDAQ:BIIB) Rituxan. The last two have been approved to treat rheumatoid arthritis, another autoimmune disease where the body attacks itself.

Investors punished Aspreva with a 5% drop in its stock price Monday. That seems a little harsh, given that the data from the trial was already known. It's nearly impossible to get the FDA to approve a drug that doesn't meet its primary endpoint, so I'm not sure why investors thought that the company had any other choice than to wait until after the maintenance phase to file a New Drug Application.

Sure, it would have been nice if the drug had worked as an induction therapy, but the maintenance phase is what could produce a substantial income for the company. After all, that phase lasts much longer than the induction phase.

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