A series of allergy shots may reduce symptoms of seasonal ragweed allergies. This study will determine whether taking a drug called omalizumab (also known as Xolair) before getting the allergy shots is more effective than allergy shots alone or other treatments, such as prescription antihistamines.

Allergic rhinitis affects 20 to 40 million Americans annually. Allergy symptoms, which can range from mild to seriously debilitating, may affect quality of life. Left untreated, allergic rhinitis can exacerbate or trigger more serious conditions, such as asthma and sinus inflammation.

Individuals with allergies react to harmless particles such as dust or pollen. Proteins in the blood called IgE antibodies treat the harmless particles as invaders and trigger an immune system response. The immune response results in harmful inflammation of healthy tissues. In ragweed allergy, inflammation occurs in the airways and causes familiar allergy symptoms like sneezing, coughing, and general discomfort.

Omalizumab is an investigational drug that has been shown to block the effects of IgE antibodies. The blocking effect of omalizumab is temporary, but giving the drug to people before their regular allergy shots may make the shots more effective.

Participants in this study will be randomly assigned to receive injections of omalizumab or a placebo before an accelerated course of allergy shots (given over 12 weeks). The participants will return for follow-up for up to one year, and they may have as many as 27 study visits.

Ages Eligible for Study:  18 Years   -   50 Years,  Genders Eligible for Study:  Both

Criteria

Inclusion Criteria

• History of seasonal allergic rhinitis
• Intend to stay in a ragweed pollen area during the ragweed season
• Baseline serum IgE level between 10 and 700 IU/ml
• General good health

Exclusion Criteria

• Current smoker
• Pregnancy
• Asthma
• Certain medications
• History of anaphylactoid or anaphylactic reactions
• History of cancer, except for basal cell carcinoma