THURSDAY, Jan. 17 (HealthDay News -- Some patients with heart failure may stand to benefit from therapy which modifies the body's immune response.
A study in the Jan. 19 issue of The Lancet found that patients with no history of heart attacks, as well as those in a milder stage of heart failure, had a reduced rate of death and of subsequent hospitalizations with such a treatment.
But the novel therapy is far from hitting hospitals or doctors' offices any time soon, experts said.
"It had absolutely no improvement [in the general study population]," noted Dr. Norbert Moskovits, director of the Heart Failure Program at Maimonides Medical Center in New York City. "The subgroup analysis is more or less a way to come up with a new study. If they show improvements in certain subgroups then next time they can look at that in a larger trial. You cannot draw any conclusions from this, really. It was a very good trial and it still showed nothing."
According to the American Heart Association, some five million Americans have heart failure. "There are half a million new cases each year. It is the number one discharge diagnosis for Medicare patients," Moskovits said. "It's a huge problem, and that's why everyone is looking for a new angle."
Heart failure is commonly treated with drugs, including ACE inhibitors, beta blockers and diuretics. "Most improve patient survival, symptoms and lifestyle," Moskovits said.
Some experts believe that inflammation plays a role in chronic heart failure. Logic would dictate, then, that interfering with the immune system and related inflammatory processes could impact the course of the disease.
But interventions that have targeted specific inflammatory cytokines (signaling chemicals central to the immune system) have not met with much success.
This has led scientists to hypothesize that affecting the immune system more generally might have a benefit.
This study involved more than 2,400 heart failure patients who were randomly assigned to receive non-specific immunomodulation therapy (IMT) or a placebo. They also had left ventricular systolic dysfunction and had undergone hospitalization for heart failure or IV drug therapy in an outpatient setting within the past 12 months.
In this case, IMT involved taking blood from patients with congestive heart failure, exposing the blood to oxidative stress for 20 minutes, then injecting the blood back into the muscle on days 1, 2 and 14, and then every 28 days for at least 22 weeks.
"Certain blood cells in these samples were more or less killed off and, by injecting them, you attenuate the immune response," Moskovits explained. "It's a very cumbersome process."
But after a mean follow-up of more than 10 months, patients in the IMT group showed only an 8 percent reduction in risk of death or hospitalization, which essentially translates into no difference.
However, the results were more impressive in two subgroups of participants: Those with no previous history of heart attack had a 26 percent reduction in risk while those classified with New York Heart Association functional class II heart failure - meaning they had only slight or mild limitations in their activities -- had a 39 percent reduction in risk.
Both of these subgroups were younger and had less severe disease than the entire group of participants.
There was also a trend toward a lowering in C-reactive protein (CRP) concentrations in the IMT arm. CRP is a marker of inflammation and this finding, the authors said, indicates that the concept of treating heart failure with immunomodulation is not yet dead.
But long-term affects also need to be investigated. "By attenuating the immune response, do you subject patients to a higher risk for infections, for cancer?" Moskovits asked. "There are a lot of questions."
Moskovits also pointed out that many therapies for heart failure are counterintuitive. Beta blockers, for instance, were thought for many years to be contraindicated for heart failure. Similarly, a medication to improve heart muscle function in heart failure patients ended up worsening their survival.
The current study was funded by Canadian biotech company Vasogen. Employees of Vasogen were involved with the trial. Authors received an honorarium or travel support or both from the company.
There's more on heart failure at the American Heart Association.