&TC For the 40 million Americans with the sneezing, sniffling, nose-stuffing miseries of allergic rhinitis, there's good news: It may be possible to avoid the hell weeks of pollen season by taking an immunity-boosting drug by mouth, instead of being subjected to allergy shots every week for a year.
But the drug won't be widely available for at least three to five years, according to researchers at the Johns Hopkins Asthma and Allergy Center.
The new treatment, already announced at allergists' meetings, was presented at a seminar at the Hopkins Bayview campus yesterday.
Developed by Immunotec, a California-based biotechnology company, it's been tested over the past several years on small groups of ragweed-allergy patients at Hopkins.
It is, however, still experimental: "Much more rigorous testing is needed" before it becomes available to the mass of allergy sufferers, said Dr. Peter Creticos, assistant professor of medicine and medical director at the Hopkins allergy center, and principal investigator on the ongoing study.
The study has determined that large doses work best: The effective amount, taken over a period of 70 days, is "100 times what you'd get in a year of allergy shots," Dr. Creticos said.
The formulation he's been using contains ragweed extract in a sugar-and-alcohol base, and this apparently remains intact until it reaches lymphoid tissue in the small intestine, causing a resistance-building reaction from the immune system.
Participants in the high-dose studies began taking the extract in mid-July, one month before the onset of ragweed season, starting with one drop of the medication and building to 20 drops twice a day; they continued this dose through the first few days of October.
In the 1989 experiment, those who took the ragweed extract had a "50 to 65 percent reduction in symptoms" compared with a similar group who took a placebo on the same schedule, Dr. Creticos reported. Blood tests of subjects showed an increased level of an immune system factor "that let us know we were stimulating the immune system," he said.
The most significant side effect, found in a few patients, was a feeling of "tightness" in the throat, which was probably an allergic reaction, he said.
Still to be determined, however, is whether this particular dose is indeed the best or whether something less than daily administration will work as well and whether the resistance achieved after a year of two can be maintained without further doses.
Similar experiments will be done with other allergens as well. The National Jewish Center for Asthma and Allergic Disease in Denver is working with oral administration of cat allergen, Dr. Creticos said. He is planning another trial with ragweed allergen this summer, and will begin recruiting volunteers for oral tests with extract from grass and tree pollen before the onset of allergy season next year.
"The real key to managing people with allergic disease is preventive therapy, trying to turn the disease process off before it gets started," Dr. Creticos said.