By Lisa Richwine
GAITHERSBURG, MD, Jan 31 (Reuters) -- A chemotherapy drug called
Novantrone should become the first government-approved treatment for advanced
forms of the disabling neurological disease multiple sclerosis (MS), federal
advisers said Friday.
A panel of experts that makes recommendations to the Food and Drug
Administration (FDA) voted that Novantrone, made by biotechnology company
Immunex Corp., could safely slow the progress of advanced stages of MS, which
can lead to paralysis, vision loss and death.
The FDA usually follows its panels' advice and is expected to decide in
the coming months whether to approve Novantrone for MS patients who are
experiencing flare-ups of symptoms, such as difficult movement and coordination
and blurred vision, and lose function with each episode. Such stages are harder
to treat than the earlier stages of relapsing-remitting MS, in which patients
return to nearly normal function during periods of remission.
About 350,000 Americans have MS, and about half are in late stages. Panel
member Dr. Howard Weiner of Brigham and Women's Hospital in Boston,
Massachusetts, said doctors already use anti-cancer drugs in MS treatment, but
formal FDA approval would "legitimize" the practice and expand Novantrone's use.
"It's an important step in our goal to control and ultimately cure MS,"
Weiner said.
The panel endorsement also was noteworthy for Seattle-based Immunex, best
known for its arthritis drug Enbrel and cancer drugs, said chief operating
officer Peggy Phillips. Winning FDA support for Novantrone in MS would put the
company into a new therapeutic arena and potentially double the drug's annual
sales to $100 million, she said. "It broadens our basic business," Phillips
said. According to Immunex's data, in a clinical trial of 194 patients, 19% of
patients who took (an inactive) placebo suffered a significant loss of ability
over 6 months compared with only 7% given the highest dose of Novantrone.
Novantrone patients also experienced 69% fewer serious relapses than the placebo
group.
Novantrone, known generically as mitoxantrone, has been sold in the United
States since 1987 as part of a chemotherapy regimen for attacking leukemia. In
cancer treatment, some Novantrone patients suffered congestive heart failure or
a decrease in heart function, and panel members considered whether giving such a
potent agent was appropriate for MS.
In a clinical trial for MS, Novantrone injections once every 3 months for
2 years produced nausea, hair loss and other "manageable" side effects, said Dr.
Richard Ghalie, Immunex senior director for clinical development. Serious side
effects could be avoided by limiting treatment to 2 or 3 years and monitoring
patients' hearts closely, Ghalie said.
All but one panel member agreed the drug was safe enough to win approval.
With proper precautions, "the likelihood of cardiac toxicity is very low," said
Dr. James Grotta of Mackenzie Health Sciences Centre in Canada.
In patients with MS, the immune system attacks the protective sheath
surrounding nerve fibers in the brain and central nervous system, causing scars
that interfere with transmission of signals from the brain. Novantrone likely
works by reducing the immune system's attack on the nerve coating, Immunex said.
Three drugs are already on the market for early stages of MS, Biogen
Inc.'s Avonex, Betaseron by Chiron Corp. and Copaxone by Teva Pharmaceutical
Industries. American Home Products Corp. owns a majority stake in Immunex.
