美国国家公共电台 NPR--More pollen, more allergies: Personalized exposure therapy treats symptoms（在线收听）

More pollen, more allergies: Personalized exposure therapy treats symptoms

Transcript

If you're sniffling and sneezing you're not alone. Mild winters, like the one the eastern U.S. has had, can bring longer allergy seasons, as warmer temperatures prompt some plants to produce more pollen.

For the millions of Americans who battle allergies, taking over the counter antihistamines, often combined with a steroid nasal spray, is enough to tamp down symptoms temporarily. But Abigail Bortnick, 41, wanted a way to prevent allergic reactions over the long term.

"I had really bad seasonal allergies," Bortnick says. Tests showed she was allergic to grasses and weeds, and she recalls feeling lousy when pollen counts rose. "I would have a runny nose, itchy eyes, the whole deal," says Bortnick, who lives in the Washington, D.C. area.

Allergy shots were one option, but with young children and a busy career, it wasn't convenient to drive to the doctor's office each week to get a shot. So, her allergist offered her an alternative, called sublingual immunotherapy, known as SLIT, a form of exposure therapy. She was given liquid drops she can administer herself. "I liked the idea of not having to go in for shots and being able to do it at home," Bortnick says.

Five drops, personalized serum

The serum comes in a small bottle with a pump on top. Once each day she puts five drops under her tongue. "It makes it easy," Bortnick says. She can't eat or drink for 30 minutes, so she aims to take them at the same time every day, so they don't interfere with meals.

She started the allergy drops a few years ago and has seen a significant improvement. "I've absolutely noticed that my allergies are much better," Bortnick says. She's also noticed she has more energy, perhaps because she's sleeping better due to less congestion and inflammation. When she starts a new vial she sometimes gets a "slight bit of itchiness" in her mouth, but that subsides quickly. And at the height of grass pollen season she still takes Claritin, but her symptoms are much less severe.

Both allergy shots and SLIT are forms of allergy immunotherapy. Patients are exposed to very small amounts of the specific things they're allergic to with the goal of training the immune system to tolerate them, gradually, over time. Doctors make SLIT allergy drops the same way they make allergy shots, mixing extracts of allergens. For each patient, the serum is personally tailored to include the specific mix of irritants that trigger their allergies.

"Part of the beauty of the therapy is its convenience," says Dr. Rachel Schreiber, an allergist in Rockville, Maryland who treats Bortnick. Schreiber says patients typically stay on SLIT for several years. "We reevaluate yearly to determine whether we should continue the therapy," she explains. Sometimes patients stop too early and symptoms can recur. "It's easy to restart," in those cases, Schreiber says, and many of her patients improve over time.

Tablets, too

There are two kinds of sublingual immunotherapy, the liquid drops mixed by allergists that Bortnick takes, as well as dissolvable tablets, available for single allergens. The Food and Drug Administration has approved four tablets, including one for ragweed, one for dust mites, and two grass pollen allergy tablets, including one for timothy grass. The tablets melt within a minute or two of being placed under a person's tongue. The American Academy of Allergy, Asthma and Immunology says the tablets have been shown to provide long-term improvement.

The most common side effects of the tablets are temporary itching or burning in the mouth, which typically resolves quickly. Studies show the tablets have a good safety profile, though a severe allergic reaction is possible, so patients on SLIT tablets are also prescribed an epinephrine auto injector, known as an Epi-Pen. Typically, insurance covers the cost of these tablets.

"They're very effective," says Dr. Howard Boltansky, an allergist at Johns Hopkins, but the main downside is that the SLIT tablets each target only a single allergen. Since most people are allergic to multiple things, many patients prefer the drop option.

Off-label use

Boltansky has been in practice more than 35 years, and recently started offering SLIT allergy drops. (He sees patients at Hopkins' otolaryngology center in Lutherville, Maryland.) "The use of sublingual immunotherapy drops has increased because of the ability to include multiple allergens that are not available in the currently FDA approved tablet, " Boltansky says. And, as patients learn about this option, they like the flexibility and convenience, which helps explain the increased interest too, he says.

The drawback is that the SLIT allergy drops are not FDA-approved, so they are not covered by most insurance, Medicare or Medicaid.

Boltansky explains, when he makes the allergy drops, he uses the same FDA-approved extracts he uses to make allergy shots. The only difference is, instead of injecting the serum into a person's arm, it's put into a dropper-bottle, for the patient to administer at home. So, the drops are an 'off-label' use of the extracts. "I am completely comfortable using allergy extracts that are FDA approved in an 'off-label' fashion," Boltansky says, pointing to an excellent safety record.

In Europe, many doctors have used this approach for years, Boltansky says. And, just like with the SLIT tablet, doctors also prescribe an Epi-Pen to patients taking the allergy drops, though he says serious allergic reactions are rare.

When a patient begins sublingual immunotherapy, the exposure to the allergens is very controlled. "We start off giving people small amounts of what they're allergic to," Boltansky says. "Gradually, as their body says it's OK, we increase the dose a little more," he says. The drops are made from purified extracts, so Boltansky has a bottle of ragweed pollen, another for tree pollen, as well as extracts for dust mites and cats. So, if a person is allergic to all four of these, "we mix them together into a customized vial of allergy drops," he explains.

"When we start someone on immunotherapy, whether it be drops or a shot, we approach it as initially a test," Boltansky says. They try it for about six months, and if they're doing well, they continue the treatment. He says about 80% of patients respond well, and the treatment usually lasts 3 to 5 years.

Not all allergists offer SLIT allergy drops, given the "off-label" status, and the lack of insurance coverage. "There is a wide range of effective and ineffective doses of SLIT liquid formulations," according to the American Academy of Allergy, Asthma and Immunology. That's why people should find a doctor who is experienced at testing and formulating an immunotherapy treatment, such as a board-certified allergist. Also, some board-certified otolaryngologists (ear, nose and throat doctor, known as ENT's) have expertise in SLIT.

Abigail Bortnick pays about $600 a year out of pocket for her allergy drops. "I did not love that it's not covered by insurance, but I thought the convenience factor outweighed the cost," she says.

Boltansky says he'd like to see more research to show how effective SLIT allergy drops are in preventing symptoms. "I'm hopeful that over time the studies will get done and the FDA will review them, and that they will be approved," Boltansky says. In the meantime, doctors will continue the off label use for patients who are good candidates for immunotherapy.