SUMMARY. The approval of new formulations of orally inhaled combination products encompassing known inhaled corticosteroid (ICS), and/or long acting β2 agonist (LABA) moieties necessitates the comprehensive assessment of current safety concerns, which may be dose- or formulation-dependent. In addition, establishing therapeutic equivalence to an already approved reference product is difficult. Clinical studies designed to gain regulatory approval, often – due to shortcomings in their design – present assay insensitivity, and thus an innate inability to confirm their aim, which is to unquestionably establish that the new product shares the same favourable risk/benefit profile as the established reference product. Especially for sensitive patient populations, such as children, adolescents and patients with more severe disease, these shortcomings cannot be overlooked, as they constitute a significant risk for the individual patient. Pneumon 2009; 22(2)