The purpose of this study is to identify an effective dose of allergen-specific immunotherapy for cat hair (Felis domesticus) administered by the oral/sublingual route.

This was a phase 2, randomized, double-blind, placebo-controlled, parallel groups study conducted in 3 centers in the US (NCT00689299). Study drug was sublingually dosed once daily as 0.15 mL of US standardized cat hair extract dosed either undiluted, as 1:10 dilution, or placebo. Target dose was obtained on Day 3 of dose titration escalating through 1:100 and 1:10 dilutions on Day 1 and Day 2 in the high dose group or placebo and 1:100 dilutions in the low dose group. Treatment duration was 20 weeks. Adult (>18 years) study subjects had positive history for cat allergy without asthma, positive skin test to cat allergen, absence of immunotherapy during the prior 2 years, and absence of other confounding baseline conditions. The primary outcome parameter was average Total Symptom Score (TSS) during a 1-hour cat chamber exposure. TSS is the sum of 7 items rated from 0 - 3 (none to severe) for nasal symptoms (rhinorrhea, nasal congestion, nasal itching, and sneezing) and non-nasal symptoms (eye watering, eye itching, and itching palate/ ear/ throat).

Inclusion Criteria:

• Male and female patients between ages of 18 and 55 years (inclusive).
• Written informed consent to participate in the study.
• Documented allergy to cat hair as demonstrated by a positive epicutaneous skin test (wheal >3 mm) and symptoms of allergic rhinitis during exposure to cats.
• Female subjects of childbearing potential, defined as not surgically sterile or at least 2 years postmenopausal, must agree to use one of the following forms of contraception from screening through the 4 week follow-up period following the last dose of clinical trial: hormonal begun >30 days prior to screening, barrier, intrauterine device or vasectomized partner (6 months minimum).
• No clinically significant abnormal findings on physical examination, with the exception of head, ears, eyes, nose, and throat (HEENT) findings consistent with allergic rhinitis, medical history, or clinical laboratory results during screening which would jeopardize the safety of the subject or impact validity of study results.

Exclusion Criteria:

• Previous allergen immunotherapy (subcutaneous immunotherapy (SCIT), oral immunotherapy, sublingual immunotherapy (SLIT) or recombinant peptide) for cat within 24 months of Screening Visit.

• History of severe allergic reaction requiring medical intervention.

• Intolerance of or severe allergic reaction to previous immunotherapy (SCIT, oral immunotherapy, SLIT, or recombinant peptide).

• Allergy to any of the non-antigen ingredients in the study drug formulation, including, but not limited to: Food, Drug and Cosmetic Act (FD&C) Yellow #5, Red #40 and Blue #1; sodium chloride; sodium bicarbonate; and glycerine.

• History of asthma requiring daily medication.

• Subjects receiving anti-IgE monoclonal antibodies.

• Congenital immune deficiency or acquired immune suppression. Causes of acquired immune suppression may include, but are not limited to, systemic illnesses such as malignancy and infection, the use of medications such as corticosteroids and chemotherapeutic agents, and radiation therapy.

• History of organ transplant, hematologic malignancy, autoimmune disease, myocardial infarction, or congestive heart failure.

• History of clinically significant gastrointestinal, renal, hepatic, neurologic, hematologic, endocrine, oncologic, pulmonary, psychiatric, or cardiovascular disease, or any other condition which, in the opinion of the Investigator, would jeopardize the safety of the subject or impact the validity of the study results.

• Inability or unwillingness to stop using drugs that may inhibit the wheal-and-flare reaction or rhinitic response prior to the study and for the duration of dosing clinical trial material (CTM), with the exception of protocol-specified rescue medications provided by the study site for use after Study Day 0. This includes, but is not limited to:

  • Decongestants for 3 days prior to Study Day 0
  • H1 antagonists (antihistamines) (oral, nasal or ocular) for 7 days prior to Study Day 0
  • Topical intranasal corticosteroids for 14 days prior to Study Day 0
  • Cromolyn or nedocromil for 14 days prior to Study Day 0
  • Systemic corticosteroids for 28 days prior to Study Day 0
  • Tricyclic antidepressants for 28 days prior to Study Day 0
  • Leukotriene modifiers for 7 days prior to study Day 0

• Inability or unwillingness to stop using drugs that may inhibit the ability to treat a severe allergic adverse event. This includes, but is not limited to: beta blockers such as atenolol (Tenormin®), metoprolol (Lopressor®, Toprol-XL®) and propranolol (Inderal®, Inderal LA®) for 14 days prior to Study Day 0 and for the duration of the study.

• Female subjects who are trying to conceive, are pregnant, or are lactating.

• Positive serum pregnancy test at screening or a positive human chorionic gonadotropin (HCG) urine test on Study Day 0 prior to administration of study drug for women of childbearing potential.

• Positive blood screen for human immunodeficiency virus (HIV), Hepatitis B surface antigen (HbSAg), or Hepatitis C.

• Forced Expiratory Volume in 1 second (FEV1) <70% of the predicted value.

• History of alcohol or drug abuse within the year prior to the Screening Visit, or current evidence of substance dependence or abuse.

• Participation in a clinical trial or receipt of a non-FDA approved therapy within 30 days prior to the Screening Visit.

20 weeks treatment plus 30 days post treatment followup.

Both SAEs reported in this study occurred in the 30 day post treatment followup, and were classified as not treatment related.

Adverse events: 41%, 58%, and 45% > 5% in Group A, B, and C, respectively.