Biogen Is `Guardedly Optimistic' Amevive Will Get Approval from FDA Panel
By: Laura Johannes, Staff Reporter of The Wall Street Journal
CAMBRIDGE, Mass. -- Biogen Inc. (NasdaqNM: BGEN - Newsis "guardedly optimistic" that its psoriasis drug Amevive will get the green light from a Food and Drug Administration panel this Thursday after what is expected to be an exhaustive review of its safety, said company executive vice president Thomas J. Bucknam.
The panel, chaired by Robert Stern, a dermatologist at Beth Israel Deaconess Medical Center in Boston , will look closely at safety issues, including the fact that the drug's mechanism of action involves killing cells involved in the body's immune system, or its defenses against foreign invaders.
"We've worked with the FDA very closely in designing the trials and looking at the safety issues," Mr. Bucknam said. "We just hope we don't see any surprises."
Investors in the biotechnology sector will be closely watching the hearing for Amevive, which is the first of a wave of experimental psoriasis drugs to reach an FDA panel. These drugs, including one being developed by a Genentech Inc. ( DNA) and Zoma Ltd. partnership, will vie for a slice of a market industry watchers peg at about $2 billion a year. If the panel recommends approval, Biogen would likely get the go-ahead to sell Amevive later this year, or early next year.
About 4.5 million Americans have psoriasis, which causes itchy painful reddish patches on the skin, Biogen said. Of those, about a third have moderate or severe disease, which would likely need more powerful treatment than skin creams or light therapy. Existing drug therapies - including the immune-depleting cyclosporin and the cancer drug methotrexate - are highly toxic and can only be taken for limited periods.
Amevive's claim to fame is that its efficacy, while comparable to that of cyclosporin or methotrexate, lasts an average of seven months after a 12-week course of weekly injections. Amevive also, at least on the face of it, appears to be much safer than cyclosporin, which harms the kidneys, and methotrexate, which poisons the liver when given for long periods. Patients in Biogen's clinical trial safely kept their psoriasis under control for as long as four years with periodic cycles of Amevive as needed.
But Amevive does have one Achilles heel. It works by killing immune-system cells, raising concerns that it could hamper the body's ability to fight off infections. People on the drug see their blood count of T-cells, the workhorses of the immune system, fall by 30%. The immune-system depletion is "clearly the thing they (the FDA) are focusing on," Mr. Bucknam says.
The company's position is that killing these cells - even if it sounds extreme - is a highly effective way to treat psoriasis, because the disease is caused when the body's immune system goes overboard. The drug specifically targets a type of T-cells, called CD45RO+ cells, which are very involved in causing psoriasis. These cells, however, are also part of the team that fights off colds, flus and other infections.
Some have called the immune-system depletion a "side effect" of Amevive, but in fact it is "how the drug works," Mr. Bucknam said, adding, "If we weren't able to do this we wouldn't be able to produce efficacy."
The T-cells still remain in "normal range" after the treatment, since most psoriasis patients had unusually high levels before taking the drug, he said. Most importantly, the company said, test subjects' ability to fight off colds, flus and other infections was the same in the groups receiving Amevive and in those receiving a placebo, or dummy pill.
That means that, if there is a problem, it would only show up if the drug were tested in a much larger group of people.
Amevive solidly met efficacy goals set by Biogen and the FDA, Mr. Bucknam said. Those goals include a 75% or greater improvement in the Psoriasis Area and Severity Index, a scale which measures the thickness, redness and amount of patches on the body. Patients also saw significant improvement in their quality of life, measured by the impact of the disease on their work and social lives. |
