Safety Study of Ragweed-SPIRE in Subjects With Ragweed Allergies and Asthma

Inclusion Criteria: * Male or female, aged 18-65 years. * Asthma treated by inhaled SABA or inhaled SABA plus low-medium dose ICS in 6 weeks prior to randomisation. * A reliable history consistent with moderate to severe rhinoconjunctivitis on exposure to ragweed for at least the previous two ragweed seasons. * Positive skin prick test to ragweed * Ragweed-specific Immunoglobulin E (IgE) ≥ 0.35 kU/L. Exclusion Criteria: * History of life-threatening asthma. * Uncontrolled asthma according to GINA * FEV1 of \< 70 % of predicted, regardless of the cause. * Administration of adrenaline (epinephrine) is contraindicated (e.g. subjects with acute or chronic symptomatic coronary heart disease or severe hypertension). * History of severe drug allergy or anaphylactic reaction to food. * A history of any significant disease or disorder (e.g. immune system, pulmonary, cardiovascular, gastrointestinal, liver, renal, neurological, musculoskeletal, endocrine, metabolic, malignant, psychiatric, major physical impairment, history of alcohol or drug abuse)