This study will evaluate the safety, tolerability and efficacy of a single dose level of KB003 in subjects with inadequately controlled asthma.

Key Inclusion Criteria:

• A diagnosis of asthma established for at least 2 years
• Symptomatic asthma as defined by the Juniper Asthma Control Questionnaire
• Symptomatic asthma despite stable treatment with inhaled corticosteroids fluticasone or budesonide, or other corticosteroids, for at least 12 weeks
• Currently receiving inhaled long-acting beta agonist (LABA) or previously documented LABA intolerability or lack of responsiveness
• At least 2 exacerbations (no more than 6) in the previous 12 months that required systemic corticosteroids or at least a doubling of daily oral dose

Key Exclusion Criteria:

• Acute asthma worsening (requiring emergency room visit, hospitalization, urgent care, physician visit, or change in asthma medications) or lower respiratory tract infection requiring the use of antibiotics, within 4 weeks prior to Screening Visit.
• History of life-threatening asthma with admission to the intensive care unit requiring the use of mechanical ventilation within the past 12 months
• Use of any immunosuppressive or immunomodulatory agents within 12 weeks or an investigational agent within 4 weeks prior to Screening Visit
• History of any cardiovascular, neurological, hepatic, or renal condition
• History of smoking within the past 12 months