Up to 1,200 patients are enrolling in an international study to evaluate a new form of allergy immunotherapy which, if successful, will require as few as four allergy shots, given monthly, to rid a patient of an allergy to cat dander.

Current immunotherapy for cats takes about three years and often more than a hundred shots to complete.

“Use of immunotherapy has always been limited by the long treatment required,” said allergist Dr. Harold Nelson of National Jewish Health in Denver, who is heading the project. “If the current study confirms earlier findings, it could be a major step forward for allergy treatment,” he said in a news release.

With traditional allergy immunotherapy, multiple injections of protein triggers like cat dander or pollen are given in small then increasing amounts over a long period of time. The idea is to gradually build tolerance and, ultimately, to desensitize the patient to the allergen. While this type of vaccination is currently the only way to treat the underlying allergic disease (rather than just allergy symptoms), it is a fairly invasive, costly and time-consuming, since patients must make numerous visits to the doctor.

Cat allergy is one of the most common allergic disorders, and a frequent trigger for asthma. The protein in cat dander that causes almost all symptoms is “fel d 1”, and the new vaccination therapy, called ToleroMune, works by injecting seven tiny protein fragments or “peptides” of this cat protein, as opposed to the whole protein.

By using the fragments, which aren’t large enough to provoke an allergic reaction, studies to date show that patients can become desensitized to cat much more rapidly and with far few side effects. Unlike the proteins used in traditional immunotherapy, as the protein fragments are not large enough to cause a reaction.

The study is expected to involve about 1,200 participants at National Jewish Health as well as at more than 100 centers in the United States, Canada, and Europe. Researchers hope to confirm earlier findings which showed that after four shots of ToleroMune, which has been developed by the British firm Circassia Ltd., many patients became desensitized and remained so a year later.

The study, which put 123 people with ragweed allergy in a specially-controlled room with their allergen for three hours, found that those who were also allergic to dogs, cats and dust mites developed symptoms faster, or experienced stronger symptoms, than those who didn’t have the other allergies.

However, the differences between the two groups lessened as the hours went on (they filled out questionnaires every 30 minutes) suggesting that once ragweed season is in full swing, everyone is affected equally.

Lead author of the study, Dr. Anne Ellis, and her team at Kingston General Hospital in Ontario suggest that to avoid this early, intense reaction, ragweed, allergy sufferers should treat their other allergies with immunotherapy or year-round allergy medication.

Another option is to limit exposure to dogs or cats leading up to ragweed season.

Idea: Hypoallergenic Cat

What’s Involved: Genetically engineering a cat that doesn’t have the gene that makes Fel d 1 protein, which causes the majority of allergic reaction. Once a colony of hypoallergenic cats is established, kittens could be bred using “traditional” methods.

Where We Stand: In 2006 a company called Allerca Inc. claimed to have bred the world’s first hypoallergenic kittens and Time magazine hailed them as one of the best inventions of the year.

But the company and its founder have been the subject of controversy, with the media and a dedicated website questioning whether the firm, now called Lifestyle Pets, really has sneeze-free cats.

But this is not the only company in the hunt for the hypoallergenic kitty. Dr. David Avner, an emergency room physician in Denver, has been working with molecular biologists on silencing the Fel d 1 gene for years, and so far has come up empty-handed.

This past summer his team thought they had successfully knocked out the gene, which could lead to the breakthrough they’ve hoped for.

While Avner admits to being “optimistic” in predicting when his company, Felix Pets, will have cats on the market, he says there’s little doubt that in 10 years, a hypoallergenic cat will be in people’s homes.

“Without question, someone is going to do it. It’s too obvious an application of the technology, and the desire for people to have allergen-free cats is too high for it to go unrealized.”

Idea: Herbal Tablets for Asthma

What’s Involved: The Antiasthma Herbal Formula (ASHMI) is a tablet containing three traditional Chinese herbs. A study of patients in China shows it improves lung function and reduces use of bronchodilators.

Where We Stand: Dr. Xiu-Min Li at the Mount Sinai School of Medicine and her colleagues continue to study ASHMI in mice and people, comparing it to using corticosteroids. New, unpublished data show that eight weeks after mice stop taking the corticosteroids, their asthma symptoms return when they are exposed to triggers.

However, the mice on the herbal formula are still protected eight weeks later. Safety studies in humans have been completed, and Phase 2 efficacy studies are continuing.

One of the benefits to using ASHMI, instead of a steroid, is that there are fewer side effects, such as weight gain. However, Li says corticosteroids will be the standard treatment for asthma for years to come.

“The practical protocol will be to have a herbal remedy that will reduce the steroid’s side effects and help to maintain the protective effect,” she says.

Idea: Quick-Acting Allergy Shots

What’s Involved: Currently, immunotherapy to environmental allergies such as trees, grass, ragweed and cats, sometimes called allergy shots, requires numerous needles over several years. The shots also carry the risk of anaphylaxis in some individuals. Now, a few companies are developing therapies to make the treatment process far shorter and also safer.

Who Reacts

Even our understanding of the prevalence of pet allergies is fuzzy. Although an estimated 20 to 30 per cent of young adults will react to at least one airborne allergen, studies have shown early exposure to animals (which researchers now suggest can have a protective effect), where you live, and whether you experience asthma, hay fever or both can all influence the development of allergies to animals.

New research from the U.S. National Institutes of Health shows that cats are the single biggest trigger for asthma, causing reactions in 29.3 per cent of asthmatics. A Swedish study, meantime, found 40 per cent of kids with asthma reacted to cats, 34 per cent to dogs, and 28 per cent to horses.

For the kids who got runny noses and itchy eyes, 49 per cent reacted to cats, 33 per cent to dogs, and 37 per cent to horses.

Dr. Jeffrey Davidson, an allergist in San Francisco and a clinical professor at the University of California San Francisco, says it’s fair to expect that as the incidence of allergic disease grows, so does the number of people reacting to animals. And while cat allergies are by far the most prevalent, people can be sensitized to any animals with feathers and fur, including dogs, guinea pigs, mice, birds, and ferrets.

The Symptoms

The range and severity of symptoms is vast, and includes itchy, runny nose and sneezing, irritated, watering eyes, wheezing and shortness of breath, eczema and hives. “Some people say they don’t have a problem unless they touch the pet and touch their eyes,” Davidson said. “And there are other people who walk into a room where there is a cat, or there has been one, and they will have an asthma attack.”

The Allergens

The culprits setting of these reactions are a series of proteins found in concentrated amounts in dander (flakes of dead skin), saliva and oil called sebum that hair follicles secrete to protect fur and skin. In some animals, allergenic proteins that originate in the blood are released through urine. The cat’s most prominent allergenic protein is called Fel d1, and its counterpart in dogs is Can f1.

Dr. James Ransom, an allergist in Topeka, Kansas and clinical instructor at The University of Kansas Medical Center, says cats’ constant grooming and indoor litter boxes mean these allergens are continuously evaporating into indoor air. A pet lover might reason a hairless cat or a short-haired dog should be fine. Not necessarily. Ransom says that, regardless of their fur, pets still emit the allergy-causing proteins from their skin, glands, dander, urine and saliva.

Plan B Solution

Ransom says if a patient has a severe reaction to animals or develops asthma, he’ll advise that the pet has to go. But “getting people to get rid of pets is very difficult.”

His Plan B is to tell the family to minimize the exposure. First, someone not allergic to the animal should wash it once a week. Next, the pet should never be allowed into the allergy sufferer’s bedroom. The pet’s roaming area in the house should be reduced to exclude areas where the allergic person spends much of his or her time. Finally, cloth-covered furniture and carpeting (which Ransom calls the “reservoir of allergens”) must be replaced with leather or vinyl furniture and hard floors such as linoleum or tile.

Although some shampoos and sprays claim to reduce how much allergenic protein your pet totes around, Davidson says washing a pet with water alone is probably just as effective. Wipe down a cat with a damp cloth instead of bathing him, the specialist advises, to avoid “losing your forearms.”

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