Efficacy and Tolerability of Adjunct Metformin for Multibacillary Leprosy

Inclusion Criteria: * Participant is a male or female, aged ≥18 and ≤65 years. * Participant is newly diagnosed with MB leprosy and has been receiving MDT ≤ 28 days. * Participant is willing and able to give informed consent for participation in the trial. * Participant is willing to adhere to study follow-up schedule for 48 weeks. Exclusion Criteria: * Participant has received MDT \>28 days for the current episode of MB leprosy, prior to study enrolment. * Presence of leprosy reaction and/or nerve function impairment requiring systemic corticosteroids on screening/enrolment evaluation. * Participants who have been treated for leprosy in the past. * Chronic systemic corticosteroid use for any other medical condition on screening evaluation (chronic use defined as ≥ 2 weeks). * History of diabetes mellitus or diabetes mellitus diagnosed on screening evaluation (random blood glucose is elevated ≥200 mg/dL (or ≥11,1 mmol/L) or fasting blood glucose ≥ 126 mg/dL (or ≥7.0 mmol/L)). * History of hypoglycaemia (random blood glucose \<55 mg/dL (or \<3.0 mmol/L). * History of cardiac failure, ischaemic heart disease, alcoholism, history of lactic acidosis or states associated with lactic acidosis such as shock or pulmonary insufficiency, and conditions associated with hypoxia. * History of intolerance or hypersensitivity to metformin. * Estimated glomerular filtration rate (eGFR) ≤30 mL/min/1.73m2 calculated by the CKDEPI equation. * AST or ALT ≥3 times the upper limit of normal (ULN) on screening evaluation. * Any serious medical condition for which participation in the trial, as judged by the investigator or treating physician, could compromise the well-being of the subject or prevent, limit or confound protocol-specified assessments. * HIV-positive on screening evaluation. * Female participant of childbearing age who is pregnant (clinically confirmed or urine dipstick for human chorionic gonadotrophin hormone) or breastfeeding. * Use of metformin within 12 weeks prior to study enrolment. * Use of other regular hypoglycaemic agents, including insulin. * Participation in another research trial involving an investigational product within 12 weeks prior to study enrolment.