Orally inhaled fixed-dose combination products for the treatment of asthma and chronic obstructive pulmonary disease: not simple math

Ther Deliv. 2014 Mar;5(3):297-317. doi: 10.4155/tde.14.4.


Over the past decade, orally inhaled fixed-dose combination products (FDCs) have emerged as an important therapeutic class for the treatment of asthma and chronic obstructive pulmonary disease. However, the conceptual simplicity of inhaled FDCs belies both the complexity of their development, and the profound advantages they offer patients. The benefits of combining agents are not merely additive, and range from increased compliance via simple convenience to complex receptor-level synergies. Similarly, though, the development challenges often exceed the sum of their parts. FDC formulation and analytical method development is generally more complex than for two monotherapy products. Likewise, FDC clinical programs can easily eclipse those of their monotherapy peers and their inherent complexity is often furthered by the diverse regulatory requirements for worldwide approval. As such, the proposition of developing an orally inhaled FDC for global registration often represents a significant increase in both the potential rewards and assumed risks of drug development.

Publication types

  • Review

MeSH terms

  • Administration, Inhalation
  • Aerosols
  • Anti-Asthmatic Agents / administration & dosage*
  • Anti-Asthmatic Agents / standards
  • Asthma / drug therapy*
  • Bronchodilator Agents / administration & dosage*
  • Bronchodilator Agents / standards
  • Chemistry, Pharmaceutical
  • Drug Approval
  • Drug Combinations
  • Drug Dosage Calculations*
  • Humans
  • Nebulizers and Vaporizers
  • Particle Size
  • Pulmonary Disease, Chronic Obstructive / drug therapy*
  • Quality Control
  • Technology, Pharmaceutical / methods


  • Aerosols
  • Anti-Asthmatic Agents
  • Bronchodilator Agents
  • Drug Combinations