Abstract
Clinicians are often presented with the scenario of what to do when one medication in a drug class has failed a therapeutic trial on a patient. We encountered a patient who developed profound resistance to glargine, aspart and regular insulin, but had a rapid and sustained response to detemir. The mechanism of the increased sensitivity to detemir is unclear, but may be related to an additional carbon chain on detemir shielding it from an antibody response. This case highlights the profound impact that subtle differences in molecular structure can have on biological activity and thus patient outcomes. LEARNING POINTS: Subtle differences in molecular structure can have a profound impact on biological activity, and thus patient outcomes.Poor outcomes with one medication in a drug class should not be used to rule out the efficacy of all related medications.Detemir has been shown to be less immunogenic than other insulins, and should be considered in patients with insulin resistance.