Nov. 10, 2000 -- A new use for an old drug may help save the lives of children suffering from a life-threatening heart condition.
When five children very sick with acute myocarditis were treated with a drug called OKT3, they experienced a dramatic recovery. There is no real treatment for the disease other than supportive care. But with this experimental therapy, the children were able to regain normal heart function.
Myocarditis is an infection of the muscle tissue of the heart and is almost always caused by a virus. In children, symptoms can occur very suddenly and abruptly, and they can become gravely ill within 24 hours.
OKT3 was approved by the FDA back in 1986 and is used to suppress the immune systems of transplant patients, so their bodies don't reject new organs.
But in a study appearing in the current issue of the journal Heart and Lung Transplantation, researchers from the University of California at Los Angeles tried a new tactic to treat these children -- using OKT3. The study also included steroids and several other drugs that suppress the immune system.
"It's not actually the virus that causes the problem, but the body's immune response to it," says study author Juan C. Alejos, MD. The soldiers of the immune system -- white blood cells -- attack the virus, but they also damage the heart muscle in the process.
In transplant patients, OKT3 stops the body's response to whatever the immune system is attacking, "and hopefully, it reverses the rejection. It's the same theory here, that using the OKT3 to blunt the body's [immune] response will reduce the amount of damage to the heart," says Alejos, who is the director of the pediatric heart transplant program at UCLA.
All five children, ranging in age from 15 months to 16 years, received a combination of drugs, which included OKT3.
"We started to see results within 72 to 96 hours," Alejos says. "Their heart function started to improve. If we could keep them supported to that point, we usually knew by that point we'd see improvement."
While all of the children experienced complete recovery, one patient died as a result of other complications. The surviving patients continued taking medication to suppress their immune systems for six months, and none of them experienced a return of the disease or any long-term damage to their heart.
Since the time of the study, a total of nine patients have received the treatment, and all are doing well.
The results are very promising, says Anthony Rossi, MD, but it's really too soon to draw any conclusions. "It's a small sample set, and it's probably worthwhile to say that this is an exciting new treatment with the potential to help many children with a disorder that has no real excellent treatment -- but it's very preliminary," says Rossi, who was not involved in the study and is director of the cardiac intensive unit at Miami Children's Hospital in Florida.
It is unclear, the investigators write, whether OKT3 by itself or in combinations with the other medications is required to produce the best response.
"Up until now, we haven't had much success with other treatments," Alejos says. "In some cases, patients get through with just supportive care, and in a lot of cases, they have to go on a heart lung machine." Alejos says that heart transplants are an option for some patients, but their revved up immune systems often go on to attack the new heart.
All of these treatments have the potential to do harm to patients, but none of these drugs are harmless, Rossi points out, which is why more research is needed before the treatment can be routinely used.
The researchers agree and currently are putting together a larger study. "With only five patients in three years, it's just not enough to know if it's a real trend or just good luck," Alejos says.