This is a Phase Ib, randomized, blinded, placebo-controlled, multiple-ascending dose study in patients with seasonal or perennial allergic rhinitis to investigate the safety, tolerability, and pharmacokinetics (PK) of MEMP1972A.

Inclusion Criteria:

• Diagnosis of allergic rhinitis
• In good health, determined by no clinically significant findings from medical history, 12-lead ECG, and vital signs
• Males or females who are surgically sterilized, post menopausal for the past year, or are using two acceptable methods of contraception against pregnancy through at least 6 months after the dose of study drug

Exclusion Criteria:

• History or clinical manifestations of significant metabolic, hepatic, renal, hematologic, immunodeficiency, pulmonary, cardiovascular, gastrointestinal, urologic, neurologic, or psychiatric disorders
• History of anaphylaxis, hypersensitivity or drug allergies
• Use of a non-biologic investigational drug or participation in an investigational study with a non-biologic drug within 30 days prior to dosing
• Use of a biologic investigational therapy or participation in an investigational study involving biologic therapy within 3 months prior to dosing
• Positive blood test for chronic viral infections by: hepatitis B surface antigen, hepatitis C virus antibody, or HIV antibody