These include NCT04341935 and NCT04371978, both randomized open label studies in diabetic patients with COVID-19, with the former intended to prove the efficacy of the investigational drugs in controlling blood glucose, and the latter aimed to reveal the efficacy of the study drugs in improving the severity of the disease (52, 75); NCT04365517, also a randomized controlled open label study designed to investigate the potential respiratory role of the DPP4 inhibitor sitagliptin in diabetic patients suffering from pneumonia due to COVID-19 (76). The gene discussed is DPP4; the disease is COVID-19.