Abstract Background Long-term use of oral corticosteroids (OCS) is associated with a risk of adverse events and comorbidities. As such, a goal in assessing the efficacy of biologics in severe asthma is often to monitor reduction in OCS usage. Importantly, however, OCS dose reductions must be conducted without loss of disease control. Main body Herein, we describe the development of OCS-sparing study methodologies for biologic therapies in patients with asthma. In particular, we focus on four randomized, placebo-controlled, parallel-group studies of varying sizes (key single-center study [n = 20], SIRIUS [n = 135], ZONDA [n = 220], VENTURE [n = 210]) and one open-label study (PONENTE [n = 598]), which assessed the effect of asthma biologics (mepolizumab, benralizumab or dupilumab) on OCS use using predefined OCS-tapering schedules. In particular, we discuss the evolution of study design elements in these studies, including patient eligibility criteria, the use of tailored OCS dose reduction schedules, monitoring of outcomes, the use of biomarkers and use of repetitive assessments of adrenal function during OCS tapering. Conclusion Taken together, these developments have improved OCS-sparing asthma studies in recent years and the lessons learned may help with optimization of further OCS-sparing studies, and potentially clinical practice in the future.