The Trials of RU-486: Brain Tumor Therapy

Alhough RU-486--the pharmaceutical abortifacient-- remains a political hot potato, a few researchers around the country have begun studies into other uses of this promising drug. At Columbia-Presbyterian Medical Center, physicians are testing whether it can retard or stop the growth of meningiomas, a common type of brain tumor.

It has long been suspected that RU-486, also known as mifepristone, might have anti-cancer properties. There is good reason to suspect that it may be effective against meningiomas, explains Michael R. Fetell, MD, Associate Clinical Professor of Neurology, who is supervising the study here. The surface of meningioma cells has receptors for several kinds of hormones, including for progesterone, a normal reproductive hormone. If progesterone promotes the growth of meningiomas, it is logical to assume that RU-486, an antiprogesterone agent (originally developed as a contraceptive), might inhibit their growth.

Indeed, a small pilot study seems to bear this out, which has prompted researchers to launch a clinical trial involving several medical centers around the nation, including Columbia-Presbyterian, the only participant in the metropolitan area.

Dr. Michael R. Fetell

"The primary treatment for meningiomas is surgery," says Dr. Fetell. "But at least 10 percent of the time, the tumor recurs. If it's on the surface of the brain--the meninges--reoperation is possible. But if it recurs very quickly or appears near the optic nerve or other sites that are difficult or too hazardous to reach, we are generally reluctant to reoperate. Another option is radiation, but it has limited effects."

The researchers hope that RU-486 will offer a better alternative. "So far," Dr. Fetell emphasizes, "it's an unproved therapy."

To date, only a handful of patients have been enrolled, owing to stringent eligibility requirements. Patients must have meningiomas that are not malignant, rapidly growing, and resistant to radiation. In addition, the patients must be ambulatory and neurologically intact. As in other "double-blinded" trials, patients must agree to be randomized to receive either active drug or placebo, both taken in pill form. However, says Dr. Fetell, if a patient's tumor grows uncontrollably during a six-month period, the study will be "unblinded," that is, the code will be unbroken and if he or she has been getting the placebo, the active drug will be substituted.

Meningiomas, which account for 15 to 20 percent of all primary brain tumors, usually grow slowly and steadily. Changes in vision, cognitive impairment, paralysis, or seizures may occur, depending on the tumor's size and location. The prognosis varies greatly from patient to patient. Some survive for decades, while others quickly deteriorate. These tumors are generally not malignant, but with no room to spare inside the rigid skull, the pressure of a growing meningioma can be lethal.

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