Immunotherapy is being introduced as a form of treatment aimed at completely curing cedar pollen allergy. National health insurance previously only covered immunotherapy injections, but medication that can be taken at home was recently included in coverage and released for sale in early October.
Though there are few reported cases of the drug eliminating all allergy symptoms, it has proven to be effective at providing relief to a certain extent, which opens up some treatment options.
Immunotherapy for cedar pollen allergy involves patients being administered with gradual allergen doses, which allow the body to become accustomed to the substances, thereby suppressing the symptoms. This therapy is also known as hyposensitization treatment.
On Oct. 8, the sublingual hyposensitization drug Cedartolen went on sale. The main component of the drug is an essence of cedar pollen. Patients apply several drops of the drug under the tongue once a day and wait about two minutes before swallowing.
Those taking the drug are advised to start with 0.2 milliliters, gradually increasing to 1 milliliter by the seventh day. The procedure is repeated for two weeks, with the concentration level of the drug at around 10 per cent during the first week. The drug is then administered at normal strength during the second week. From the third week onward, about 1 milliliter of the drug should be administered every day for at least two years. Costing ¥100 per 1-milliliter dose, patients covered by national health insurance should expect to pay 30 per cent of the cost, or ¥30 per dose.
From 2010 to 2012, a 41-year-old woman in Chiba participated in a clinical trial for the drug. The woman had been allergic to cedar pollen for 20 years, and suffered symptoms so severe her runny nose would wake her up at night. But after undergoing immunotherapy she said she "felt like my symptoms were half as severe." She used to take an allergy drug every day during the pollen season, but now she says she only has to take it only several times, adding her symptoms were mild this year and last year.
According to Yoshitaka Okamoto, a professor at Chiba University's otorhinolaryngology division, the medicine's clinical tests found that patients who took the drug for 1½ years saw their symptoms during peak pollen seasons mitigated by an average of 30 per cent.
But the percentage of patients who were almost free of symptoms without taking allergy drugs during the season remained at 17 per cent, while 20 per cent had no mitigating effects from the drug.
Clinical trial patients took the medication for only a short period of time. Even so, only limited effects have been confirmed so far. More research needs to be conducted to determine how long the effects of the drug will last after patients stop taking it.
Many of the existing treatment methods for cedar pollen allergy are supportive measures including antihistamine agents, steroid drugs and laser therapy that involve applying a laser to the lining inside the nose to alleviate symptoms.
Hypodermic allegen injections are available as a treatment method that aims to completely cure the symptoms, but the procedure requires patients to visit a hospital every month for more than two years. With this in mind, the new drug offers an easier option for patients who choose immunotherapy.
Possible side effects
But it's important to exercise care about the medicine's side effects. Some major side effects include canker sores inside the mouth, swelling of the tongue and inside of the mouth, itchiness of the throat and headaches. Life-threatening anaphylaxis is also a possibility, and patients are advised to consult a doctor if they develop such abnormal conditions as hives, nausea or difficulty breathing. Patients need to exercise caution, particularly 30 minutes after taking the drug and about a month after starting treatment.
"It's rare for immunotherapy to eradicate all the symptoms, but we expect it to relieve some symptoms and reduce the amount of allergy drugs patients need to take," Okamoto said. "Prospective patients need to be aware of the good and bad points and take the drug under the instruction of a doctor qualified to administer the treatment."