Allergists are eagerly awaiting the new treatment. Clinical trials show it can significantly improve the quality of asthma patients' lives. Given by injection once or twice a month, it lets many patients cut back on other asthma drugs. In clinical trials, moderate-to-severe asthma patients who took Xolair:
- Had less severe asthma attacks.
- Had fewer asthma attacks.
- Needed fewer doses of inhaled corticosteroids.
- Improved long-term asthma control.
- Had many fewer hospitalizations for asthma.
"What we are looking at is the first antibody treatment that will diminish allergic reactions," Bassett tells WebMD. "With Xolair, we are not focusing just on treating allergy symptoms. Now we can cut down on the likelihood of having an allergic reaction to something you are exposed to."
Although last Friday's FDA approval applies only to allergy- related asthma, there's good evidence that Xolair can help all kinds of allergies.
"I am hopeful it will also have an impact on diminishing other kinds of allergic reactions: Food allergies, seasonal and indoor allergies, and so on," Bassett says. "In the future, I hope we'll be getting information on whether Xolair helps these patients as well as asthma patients."
Long and Winding Road
First submitted to the FDA in 2000, it's been a bumpy road to approval for Xolair.
First, high doses seemed to cause a dangerous blood-platelet deficiency in lab monkeys. This seems not to happen in people. But clinical trials were put on hold until extra safety studies were finished.
Next, the FDA ruled that there were too few patients in clinical trials to approve Xolair for pediatric allergic asthma patients and adults with seasonal allergy. The application was narrowed to the current indication for people over 12 years of age, pending further clinical trials.
More recently, data came to light suggesting that patients taking Xolair had an increased risk of cancer. This involved so few patients, however, that a link to the drug seems unlikely.
Another snag came from a squabble between the three drug companies developing Xolair: Genentech, Novartis, and Tanox. Tanox is developing a similar drug, known as TNX-901. A recent study showed that it can reduce allergic reactions to peanuts. Further trials of TNX-901 were cancelled. New studies are looking at the use of Xolair in people with life-threatening peanut allergy.
Xolair is a high-tech drug. It's technically known as a humanized monoclonal antibody -- a miracle of genetic engineering.
Developing the drug cost a lot -- and so will using it. Although final pricing hasn't been announced, industry observers expect the price tag to be about $10,000 per year.
Even at that cost, analysts expect nearly half a million patients to turn in prescriptions. But it means that insurance companies will be watching closely. They're not likely to reimburse patients who take Xolair for anything other than it's approved use.
How It Works
When an allergy-causing substance -- an allergen -- enters the body, nothing happens. Unless, of course, you're allergic to that substance. If you are, your body starts making a special kind of antibody called IgE. IgE looks for a special kind of cell called a mast cell, and tells it to start making a chemical known as histamine. Once the body floods with histamine, a person starts to have allergy symptoms, including allergic asthma.
Antihistamines work by blocking the effect of histamine, the chemical that triggers most allergy symptoms. Histamine is released by cells called mast cells. But Xolair goes to work much earlier in the process. It's an antibody itself -- and its target is IgE. It acts like a sponge, soaking up excess IgE before it can get to mast cells.