Inclusion Criteria:

• KCCQ CSS < 85.
• NYHA functional class II or III
• A diagnosis of HCM consistent with the current American College of Cardiology Foundation/American Heart Association and European Society of Cardiology guideline definition: unexplained left ventricular (LV) hypertrophy with nondilated ventricular chambers in the absence of other cardiac (eg, hypertension, aortic stenosis) or systemic disease with maximal LV wall thickness ≥ 15 millimeters (mm), or ≥ 13 mm with positive family history of HCM.
• For obstructive hypertrophic cardiomyopathy (oHCM), left ventricular outflow tract (LVOT) peak gradient ≥ 30 millimetre of mercury (mm Hg) during screening as assessed by echocardiography at rest or during a valsalva maneuver.
• For nonobstructive hypertrophic cardiomyopathy (nHCM), LVOT peak gradient < 30 mm Hg during screening as assessed by echocardiography at rest and < 30 mm Hg during a valsalva maneuver.
• Screening left ventricular ejection fraction (LVEF) ≥ 50%, except for those on a cardiac myosin inhibitor (screening LVEF ≥ 55%).
• For participants on a cardiac myosin inhibitor, the dose must be stable at least 3 months prior to screening. Participants on cardiac myosin inhibitor should not be scheduled for up-titration during the trial.
• Stable doses of background therapy (ie, β-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, diuretics) for at least 1 month prior to screening.

Exclusion Criteria:

• Received therapy with a sodium glucose co-transporter 2 (SGLT2) inhibitor within the past 8 weeks prior to screening.
• Previous intolerance to an SGLT2 inhibitor.
• Any previous treatment with sotagliflozin.
• Current use of thiazolidinediones or digoxin.
• Current/planned participation in another interventional clinical trial or prior participation in any interventional trial with an investigational agent within 45 days of screening.
• Known infiltrative or storage disorder causing cardiac hypertrophy that mimics HCM such as Fabry disease, amyloidosis, or Noonan syndrome with LV hypertrophy.
• History of unexplained syncope within 6 months prior to screening.
• History of sustained ventricular tachyarrhythmia (> 30 seconds) or appropriate implantable cardioverter defibrillator (ICD) discharge within 6 months prior to screening.
• Has paroxysmal, persistent, or permanent atrial fibrillation not on anticoagulation for at least 4 weeks prior to screening and/or not adequately rate controlled within 3 months of screening.
• Septal reduction therapy planned during the study period. For participants who had septal reduction therapy, the procedure should have been completed more than 3 months prior to screening.
• Cardiac surgery (eg, coronary artery bypass graft, valvular repair/replacement), percutaneous coronary intervention, or implantation of cardiac device (pacemaker or implantable cardioverter defibrillator) within 3 months prior to screening or planned during the study period.
• Presence of a cardiac resynchronization therapy device.
• Acute coronary syndrome within 2 months prior to screening.
• History of stroke or myocardial infarction within 6 months prior to screening.
• Hospitalization for heart failure or arrhythmia within 4 weeks prior to screening.
• Has known moderate or severe (as per investigator's judgment) aortic valve stenosis at screening.
• Current angina or clinically significant ischemia due to unstable epicardial coronary disease, as per investigator judgment.