Can a drug to be used in the clinic to treat a disease that failed a clinical trial?

Question

I am searching for drugs for my uncle who has prostate cancer who is afraid to take corticosteroids. I read about the drug cabozantinib, but it said it failed a 3rd phase clinical trial, even though it was equally as effective as the treatment with corticosteroids, only more expensive. Since it has not been approved due to this, I am wondering if this drug can still be used for prostate cancer?

Answer 1

When a drug fails any clinical trial, there is a reason. A little information on drug trials...

There are three phases: 1, 2, and 3 (and 4, after it is released where the FDA continues to monitor the drug)

In phase one, the drug is tested on healthy people. In phase 2, the drug is tested on people with the condition to test for effectiveness and biological effect on the body. Finally, phase 3 is a larger study where the drug is tested in multiple centers, and a large number of patients.

Drugs tend to fail for a few reasons...it is ineffective, or it isn't safe. If a drug fails any of the phases of trials, it cannot be prescribed, unless it is already approved for another purpose, in which case the doctor could use it "off label". While the research you read may have been uplifting, there is a very important reason for this.

This drug failed due to it being no more effective than the current standard (Prednisone). Since there is no significant difference in the effectiveness when compared to prednisone, it is not worth the extra risk of unknown adverse side effects when compared to corticosteroids, which is why the FDA did not approve it. In other words, there is no clinical reason to use this drug over a corticosteroid if it will not improve the patient's outcome, which this drug will not based on the research.

In short, the risk is higher than the benefit of this drug when compared to corticosteroids in treating prostate cancer. It could, however, be prescribed off label since it is already on the market for the treatment of a rare form of thyroid cancer. But such a prescription would be based on the provider's judgement, and a discussion of the risks and benefits of both drugs. Typically, a provider will only go off label if A) no drug exists to treat their condition or B) all conventional treatments have failed.