Anxious No Longer

Sometimes it's not the size of your market, but the number of indications a drug treats that determines how well it sells.

Eli Lilly (NYSE:LLY) keeps slapping them onto Cymbalta. The company said today that the Food and Drug Administration approved Cymbalta for the maintenance of generalized anxiety disorder (GAD). That would be the sixth approval the drug has gotten from the agency, including the acute treatment of anxiety.

Cymbalta has had substantial sales despite competition from cheap generic versions of other depression drugs -- Eli Lilly's Prozac, Wyeth's Effexor, and Bristol-Myers Squibb's (NYSE:BMY) Serzone -- because it's expanded into additional areas, such as treating fibromyalgia.

Source: Company press releases. YTD = year to date.

Normally, adding a maintenance phase onto an acute indication would result in a substantial increase in sales as patients start taking the drug regularly after having taken it for shorter periods of time. But Cymbalta has been approved for nearly three years for GAD, and I imagine a lot of doctors were comfortable enough with Cymbalta's safety profile to already prescribe it as a maintenance drug, even though it wasn't approved for that indication.

Eli Lilly will pick up a few of the stricter doctors now that it can market the drug for the maintenance phase, but with sales approaching $3 billion per year, don't expect the new approval to move the revenue needle all that much.

And those diminishing returns are, of course, the downside to developing a drug for multiple indications.

No diminishing returns here, says Selena Maranjian.