Let’s say drug N is developed and approved by the FDA for the treatment of a specific condition. It has side-effects such that it is also effective in the treatment of a different condition and it is not contraindicated for use in that other condition very often. Using N to treat the condition other than the one for which it was specifically approved is off-label usage of the drug, and the practice is very common. In some drugs, I think the technically off-label use has surpassed the on-label use.
So, when does the label get changed? Is it worth anyone’s time and money to change the label?
It is generally up to the manufacturer to apply to the FDA for a change in prescribing information. It might or might not be worth their while to do so. The downside would be the cost of the paperwork and studies needed to support such an application, as well as the new liability. The benefit to the company would be that they could promote the drug for that purpose, both to prescribing physicians and in advertising to the public. As I recall, the manufacturer of Neurontin was fined for promoting the drug’s off-label use, after prescriptions for neuropathic pain and migraines dwarfed prescriptions for its approved use as an anti-seizure drug.
After a drug has lost its patent protection, if you have three or four manufacturers, it’s not worthwhile for a manufacturer to apply for new indications when it has only 25% of the market. But it would be in the public interest to allow for a change if the drug is widely used for an off-label purpose. I’m not sure whether the FDA has a process to get around that problem.
I am in a drug study right now where the manufacturer of a drug approved for use in Parkinson’s Disease patients in being studied for use in patients with Restless Leg Syndrome. So I guess the expenses involved in doing the additional studies is worth it for the company.
Even the drug reference books mention common off-label uses of various drugs such as Cytotec. They do carefully note that it is an off-label use but they are pretty matter-of-fact about it.
It’s fairly common in the horse business for vets to suggest a specific drug that is NOT formally approved for use on horses, but is approved for use on cattle for the same health problem.
To get a drug approved, the company has to do extensive tests, document them, submit the documentation, and wait for approval. This is expensive and takes time. And this must be done separately for each species.
Often, drug companies will do this for cattle, because there are so many cattle raised that they can make a lot of money selling the drug. But the market for horses is much smaller, and they may decide it’s not worth the investment to go thru the effort of getting the drug approved for horses. So they don’t bother.
But cattle & horses are similar, and the drug may work fine in horses. Vets discover this, and begin using it for horses, successfully. Such a drug may become widely used on horses, without ever being approved.
And there’s no great incentive for the drug company to ever get it approved for horses, because:[ul]
[li]it will cost a lot to do that.[/li][li]it’s already being bought by horse people for use on their horses; getting approval wouldn’t increase sales much.[/li][li]as long as it’s not approved for horses, the drug company is pretty immune to lawsuits over bad reactions in a horse.[/li][/ul]
Didn’t the anti-ED use of Viagra start as an off-label use? I seem to recall something about it originally being a blood pressure med, I think? But you never see it marketed that way any more.
This is a side of the industry that I am not too familiar with, but IIRC, getting a drug approved for a second (or third or whatever) illness/usage has some benefits with respect to patents. They might not extend a patent by the same lifetime as an original new drug would get, but I think a few years/conditions can get added on in order to prevent a generic from immediately being able to market that drug product for the new indication.
I don’t think Viagra was actually on the market for another purpose before studies showed the effectiveness for ED, but Wellbutrin (the antidepressant and recently approved for seasonal affective disorder) was successfully reapproved as the stop-smoking aid Zyban by Glaxo. FWIW the Wellbutrin approval was in 1989 and Glaxo’s exclusivity patent expired in 2004.
I would think it would be very valuable to a company to be able to remarket an existing drug since a lot of the safety/stability/formulation (aka development) work is already done… it comes down to clinical trials, which are less expensive than finding a new molecule that has a good medicinal use.
And seeing as how people swear that “the generic just doesn’t work for me”, brand name companies are going to milk that brand name for all it’s worth!
To answer the OP more literally, the label changes when the FDA determines the drug is safe and effective for the new use and then the manufacturer changes the label as he is newly free to do.
IIRC Viagra was originally developed for blood pressure control but was soon discovered to be better for erectile disfunction. No big surprise, as erections and lowering blood pressure both require allowing circulatory structures to grow and somewhat engorge with blood. But it never got labeled or sold for blood pressure, that was just the motivation for its development. It wasn’t an example of off-label use.