INFO - Arthritis Today: Off-label drug use

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Arthritis Foundation

Arthritis Today

On Call

Medical Questions & Answers

02/17/2006

Excerpt:

Off-Label Drug Use

Q. I have severe rheumatoid arthritis (RA) with vasculitis that hasn't been

helped by any of the drugs I have taken. My doctor wants me to take a cancer

drug called Cytoxan. Why would he prescribe a cancer drug for RA? Can he do

that legally?

A. You're right that Cytoxan (cyclophosphamide) is a cancer drug. It is

approved by the FDA for the treatment of several types of lymphoma, leukemia

and other cancers.

Even though it is not approved for RA, studies and clinical practice have

shown it to be helpful against RA-associated vasculitis (inflammation of the

blood vessels), so rheumatologists prescribe it for that purpose.

Once a drug is approved to treat one condition, a doctor may prescribe it

for other diseases as he sees fit. This practice is called off-label

prescribing and it is commonly done.

In fact, some of the most successful drugs for arthritis-related diseases

were first prescribed off-label, because they were originally developed

and/or approved for other diseases. For example, methotrexate, one of the

most effective RA treatments, was originally developed and approved as a

cancer treatment. Doctors prescribed it off-label for RA for many years

before its manufacturer sought and received FDA approval for RA.

But methotrexate is not the only arthritis drug that was first approved for

another condition. Here are some of the others:

Sulfasalazine (Azulfidine), was first approved for inflammatory bowel

disease. It wasn't approved for RA until almost 50 years after its

development.

Cyclosporine (Sandimmune, Neoral), which was developed and used to

prevent the rejection of transplanted organs, has in recent years been

approved for the treatment of rheumatoid arthritis and psoriasis.

Chloroquine was first used during World War II to treat malaria.

Today, the chloroquine derivative hydroxychloroquine (Plaquenil) is approved

for both RA and lupus.

Infliximab (Remicade), was approved for Crohn's disease in 1998. It

was approved for RA last November.

Sometimes drugs begin to gain acceptance for off-label use purely by

coincidence. For example, in the 1940s while using chloroquine to treat

malaria patients, doctors noticed that patients who also had RA experienced

improvement in their RA symptoms. In other cases, researchers have seen a

similar mechanism between two diseases and decided to try a drug that's

already approved for one condition to treat the other.

The FDA does not prohibit the practice of off-label prescribing; however, it

does regulate the claims a drug company can make about a drug and the

diseases for which the company can market a drug. That is, a drug company

cannot market - either through advertisements or one-on-one discussions with

doctors - a drug for conditions other than those for which the drug is FDA

approved.

Once clinical practice suggests that an off-label use is successful,

controlled studies should be - but are not always - done to demonstrate the

drug's benefit. If studies confirm that a drug is useful for a condition

other than the one(s) for which it is approved, its manufacturer may choose

to pursue FDA approval for the other disease as well.

This process helps determine optimal dosages and ensure the effectiveness of

drugs for the disease conditions for which they're prescribed. So far the

maker of Cytoxan has not submitted it for FDA approval as an RA drug.

No matter which drug your doctor prescribes - off-label or not - it's

important that you know how to take the drug properly, recognize potential

side effects, and know what to do if you experience side effects.

Doyt L. Conn, MD, Rheumatologist

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