The multiple sclerosis drug Betaseron appears to be safe for long-term use, according to a study sponsored by Berlex Inc., the drug's maker.

Only the preliminary results are in. The full data are expected later this year.

The early findings focus on 234 MS patients who participated in a study of Betaseron 16 years ago. More of those who had taken 250 micrograms of Betaseron every other day in the study were still alive and walking without assistance, compared with those who had taken a placebo.

"In general, multiple sclerosis does not substantially reduce life expectancy but numerous studies have demonstrated a modest, yet clear, reduction in untreated patients," says George Ebers, research professor at Oxford University's clinical neurology department, in the news release.

The researchers presented their findings at the American Academy of Neurology's annual meeting.

Following Up After 16 Years

Multiple sclerosis is a chronic neurological disease of the central nervous system (specifically, the brain, spinal cord, and optic nerves). In relapsing-remitting multiple sclerosis, symptoms can fade and recur randomly over many years.

All participants had relapsing-remitting multiple sclerosis, the most common form of the disease.

The researchers tracked down 234 people who had participated in the original study (63 percent of the group). Most (89 percent) were still alive. As of April 2005, about 20 years had passed, on average, since participants had been diagnosed with multiple sclerosis.

When the original trial began in 1988-1990, participants were assigned to get injections every other day of 250 micrograms of Betaseron, 50 micrograms of Betaseron, or a placebo for two years.

Later, participants were allowed to stay with their assigned treatment for up to five years. When the 250-microgram dose of Betaseron was approved for use, everyone was allowed to take it. The study was conducted at 11 sites in the U.S. and Canada, all of which participated in the follow-up.

Fewer Deaths With Betaseron

Sixteen years later, more people who started with 250 micrograms of Betaseron were alive and walking, say the researchers. That's based on the people they could locate after all those years.

Of the original 250-dose group, 73 out of 78 patients were still alive (94 percent). For the 50 microgram group, 72 out of 78 were still alive (92 percent). Among the placebo group, 64 out of 78 patients were still living (82 percent).

More People Walking With Betaseron

Of the 234 patients, 99 (42 percent) said they could walk by themselves or with aides. That included half of the 250-microgram dose group (39 people), 28 from the 50-microgram dose group, and 32 from the placebo group (41 percent).

Forty-three people (19 percent) said they relied on a wheelchair or were bedridden. That included 14 people from the 250-microgram dose group, 16 from the 50-microgram dose group, and 13 from the placebo group.

The results indicate that starting the 250 microgram dose early "has a long-lasting beneficial impact," say researchers. "To date, patients treated with 250 micrograms in the pivotal trial are more likely to report continued ability to walk than those patients receiving placebo."

Researchers' Perspective

"While it is premature to draw firm conclusions from preliminary data, I am particularly struck by the mortality trend among patients in the placebo arm appearing to be threefold different than that of patients receiving Betaseron," says researcher Barry Arnason, MD, in a news release.

"The reasons for this difference are unknown right now, but hopefully, we will get a clearer understanding of why this difference occurred when the study is completed and the data analyzed more thoroughly," continues Arnason, who works at the University of Chicago's neurology department.

The full report will include data on functions such as memory, attention, and reasoning, says Ebers.

Side Effects

The follow-up data didn't include side effects. According to Berlex, possible side effects include decrease in infection-fighting white blood cells, injection site reaction, weakness, flu-like symptoms, headache, and pain.

Caution should be used with depressed patients, says Berlex. Also, the drug company recommends rotating the injection sites, noting that injection site necrosis has been reported in 5% of patients in trials.

Women should be warned about potential risks of using the drug while pregnant, and cases of a rare but potentially life-threatening allergic reaction have also been reported, says Berlex.

ByMiranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: 57th Annual Meeting of the American Academy of Neurology, Miami Beach, Fla., April 9-16, 2005. News release, Berlex. WebMD Medical Reference from Healthwise: "Multiple Sclerosis: Topic Overview." WebMD Medical Reference from Healthwise: Relapsing-Remitting Multiple Sclerosis."