Safety and effectiveness of tofogliflozin in Japanese people with type 2 diabetes: A multicenter prospective observational study in routine clinical practice

Aims/Introduction: Sodium–glucose cotransporter 2 (SGLT2) inhibitors effectively and safely reduce fasting and postprandial hyperglycemia while promoting weight loss. However, their unique mechanism of action contributes to concerns regarding their safety. We therefore carried out a large-scale, non-commercial, investigator-initiated study on the safety and effectiveness of the SGLT2 inhibitor tofogliflozin. Materials and Methods: This multicenter, open-label, uncontrolled, prospective observational study was carried out at hospitals and clinics across Japan in participants aged ≥20 years who were SGLT2 inhibitor-naïve and had an established diagnosis of type 2 diabetes. The primary endpoint was adverse drug reactions (ADRs) of special interest. Secondary endpoints included all other ADRs and adverse events, glycated hemoglobin (HbA1c), and weight loss. Results: The study, carried out from June 2014 through February 2020, enrolled 11,480 participants from 1,103 medical institutions; 6,967 participants completed the 104-week follow up. The most common ADRs of special interest were urinary and genital tract infections (1.53%), followed by volume depletion (1.25%). Hypoglycemia occurred in 27 participants (0.24%), adverse events in 1,054 (9.18%) and ADRs in 645 (5.62%). HbA1c decreased by 0.85% (95% confidence interval 0.82%–0.88%) and bodyweight decreased by 3.05 kg (95% confidence interval 2.94–3.17 kg). The HbA1c target was achieved by 51.70% of participants for target HbA1c <7.0%, 85.3% for <8.0% and 5.4% for <6.0% at week 104. Conclusions: Tofogliflozin was associated with only mild or moderate ADRs characteristic of SGLT2 inhibitors, with no unpredictable, new, serious, or high-incidence adverse events or ADRs. This independent study confirmed the safety and effectiveness of tofogliflozin in adult type 2 diabetes patients.