The future for branded antidepressants as a business looks grim. Here's the current patent expiration schedule for the four biggest sellers:
- GlaxoSmithKline's Paxil CR expires in 2008
- Wyeth's Effexor XR expires in 2011
- Forest Labs' Lexapro expires in 2012
- Eli Lilly's Cymbalta expires in 2014
There is some talk that companies will attempt to see if depression drugs can be used to treat addiction, for instance.
But a more likely scenario is that companies will try to persuade the FDA to approve antidepressants as adjunct treatments for patients with serious illnesses that may also make them depressed. This notion -- that antidepressants can fight off cancer -- may be taking things too far, but the idea of using an antidepressant in someone being treated for cancer doesn't seem unreasonable, given the often miserable side effects and procedures that cancer patients must endure.
Another example was Forest's recent attempt to get Lexapro approved for anxiety disorder. The FDA turned the company down (twice!) but you can see that the commercial strategy here is to stretch and widen the number of conditions and indications for which an antidepressant can be approved on-label.
That's one reason why Cymbalta has been such an astounding success even in the face of competition from Lilly's own generic Prozac. It isn't just a depression pill, it's also for diabetic nerve pain and fibromylagia.
In some ways, Cymbalta and drugs that look like Cymbalta, will probably be a big part of the future of antidepressants -- increasing uses, increasing complexity, and more complicated overlaps between mental disease categories. What's good for the goose is good for the gander, of course, which explains why brand managers on non-depression drugs have wondered whether their products can be extended into depression's territory. Here's one example, in which Lilly sales reps allegedly attempted to persuade doctors that the antipsychotic Zyprexa could be used for difficult depression cases.