FDA Approves ‘Microspheres’ to Starve Uterine Growths
Microscopic spheres that shrink uterine fibroid growths and save women from more extensive surgery were approved Tuesday by the Food and Drug Administration.
The “microspheres” are used to block blood vessels and, in effect, starve fibroids, relieving the need to surgically remove the uterine growths, the FDA said. With no blood supply, the fibroids shrink over a period of weeks, the agency said.
Made by Biosphere Medical Inc. of Rockland, Mass., the spheres will be sold under the brand name Embosphere Microspheres. The material was approved two years ago for treatment of two other conditions, the malformation of blood vessels and blood vessel tumors.
The new use of the microspheres is specifically for treating women who have troublesome fibroids and who no longer intend to become pregnant, the FDA said.
Blocking blood flow to treat a medical condition is called embolization. Such procedures have been used for about 25 years, the FDA said in a statement, but the Embosphere Microspheres material is the first approved in the United States specifically for uterine artery embolization.
Fibroids are benign tumors that form in the uterus, often causing intense pain, bleeding, cramps and frequent urination. Traditional treatment has been surgery to remove the fibroids or to remove the entire uterus.
Only a small incision is required to use the microspheres. The technique involves inserting a catheter into an artery in the groin and, using X-rays for guidance, threading its tip to a position within the blood vessels just upstream from the target fibroids. The microspheres are then injected through the catheter and into the blood vessel, where they form a blockage that pinches off the blood supply.
Clinical studies on 132 women with uterine fibroids showed that the microspheres reduced bleeding by 50% or more in 65% of the patients.
The FDA said 6% of the women had an allergic reaction to the microspheres. For 9% of the patients, there was no improvement or even a worsening of the bleeding.
All the patients reported significant pain for one or two days after the procedure, and there were four cases where the pain persisted beyond that period.
The FDA said that patients in the trial were followed for only six months, so it is not known whether the fibroids will return. The agency said that Biosphere Medical is to follow patients for at least three years to answer that question.
Uterine artery embolization techniques have been used extensively in some other countries, and the FDA said a worldwide search of medical literature shows there can be serious risks.
The agency said these risks include premature menopause, halting menstrual periods, pelvic infection, destruction of the uterus, hysterectomy, pregnancy complications and delayed diagnosis of uterine cancer that would have been discovered with traditional fibroid surgery.
Out of 25,000 to 30,000 uterine artery embolization procedures performed worldwide, the agency said, there have been four reported deaths.
About a third of the 600,000 hysterectomies performed annually in the U.S. are for treatment of fibroids, the FDA said.
