Trial Against INtractable Type 2 Diabetes (CAPTAIN-T2D)

Inclusion Criteria:

* From Screening 1

  * Age at least 18 years.
  * HbA1c ≥7.5% documented within 3 months prior to Screening 1. (The historical HbA1c value must have been obtained after at least 2 months on the current \[as of Screening 1\] regimen).
  * Treatment with stable and adequate doses of ≥2 injectable or oral ADMs. (An ADM will be deemed stable if the dose has been the same for at least 3 months prior to Screening 1 and without change between Screening 1 and Day 1) (An ADM dose will be deemed adequate if it is at or above the maximal labelled dose, or a sub-maximal, but not starting, dose if limited by tolerability (confer with MM if less than half-maximal dose).
  * Adequate total daily insulin is defined as at least 0.3 units/kg/day. Insulin dose will be deemed stable with adjustments of up to 20% total daily dose during the 3 months prior to Screening 1 or between Screening 1 and Day 1.
  * Use of insulin pumps or insulin brand changes (e.g., due to insurance change or shortage) are to be discussed with the MM.
  * At least one of the following

    * ≥3 stable and adequate ADMs;
    * diabetes complication (retinopathy, nephropathy, neuropathy, atherosclerotic heart disease);
    * hypertension requiring ≥2 adequately dosed AHMs;
    * adequately dosed basal or basal plus prandial insulin in addition to at least 1 other ADM; and
    * adequately dosed incretin agonist (a single or combination agent counts as one ADM) in addition to at least 1 other ADM;
    * evidence or history of osteoporosis or non-traumatic fracture (e.g., vertebral body compression);
    * or established diagnosis of a neoplastic (non-malignant) source of hypercortisolism and have failed, are ineligible for, or declined surgery.

At DST • Post-DST cortisol level \>1.8 µg/dL and serum dexamethasone ≥140 ng/dL. Patients with an established diagnosis of neoplastic hypercortisolism do not require a DST.

At Screening 2

* HbA1c ≥7.5% at Screening 2. At Day 1
* No change in, or initiation of, medications for hypertension within 1 month prior to Day 1.

Exclusion Criteria:

* New-onset diabetes (onset \<1 year in the past).
* Unwillingness to maintain with current glucose-lowering regimen during the trial.
* Unwillingness to adjust, add, replace, or discontinue current or other glucose-lowering medications during the trial as directed by the investigator.
* Unwillingness to comply with CGM or other trial procedures.
* Investigator considers the patient will otherwise be unwilling or unable to complete the trial.
* Night-shift worker or otherwise habitually awake from 23:00 to 07:00 h.
* Evidence for significant hypoglycemia while on their current diabetic treatment regimen(This includes episodes of symptomatic Level 3 hypoglycemia requiring external assistance for recovery, or CGM-documented prolonged \[\>15 min\] or repeated episodes of either Level 2 hypoglycemia leading to \>1%, or Level 1 hypoglycemia leading to \>4%, in "time below range" within 3 months prior to Screening 1 or between Screening 1 and Day 1).
* Any of the following in medical history:

  * Type 1 diabetes mellitus (T1D), latent autoimmune diabetes in adults (LADA), or familial forms of maturity-onset diabetes of the young (MODY);
  * A hemoglobinopathy or other condition which may interfere with measurement of HbA1c (e.g., sickle cell disease HbSS or other variants HbEE thalassemia, hemolytic anemia, recent blood transfusion);
  * Hypersensitivity or severe reaction to dexamethasone;
  * Pheochromocytoma, or suspicion thereof;
  * Anorexia, or other eating disorder;
  * Glucocorticoid resistance;
  * Multiple sclerosis;
  * Significant hepatic impairment (e.g., Child-Pugh Class B or C);
  * Idiopathic thrombocytopenic purpura;
  * Untreated or inadequately controlled moderate-to-severe sleep apnea (apnea-hypopnea index ≥15). (Patients whose condition has been well controlled with Continuous Positive Airway Pressure (CPAP) use for at least 3 months prior to Screening 1 are not excluded. Patients with a STOP-BANG score 5-8 should be referred for a sleep study outside the trial and may rescreen if found not to have moderate-to-severe sleep apnea);
  * Current alcohol consumption \>14 units/week or \>4 units in a single day for males, or \>7 units/week or \>3 units in a single day for females. (Patients with a CAGE score 2-4 should be evaluated further outside the trial and may be rescreened if found not to have an alcohol \[or other substance\] use disorder);
  * Untreated or inadequately controlled major depressive disorder, generalized anxiety disorder, bipolar disorder, post-traumatic stress disorder, or schizophrenia.(Patients whose condition has been well controlled with stable medical therapy, or has been asymptomatic, for at least 3 months prior to Screening 1 are not excluded); or
  * Any other medical condition (including malignancy) that is likely to interfere with trial assessments or the patient's ability to complete the trial.
  * Any of the following in medication history:
  * Any of the excluded medications listed in Section 6.9;
  * Any investigational drug within 4 weeks or within less than five times the drug's half-life, whichever is longer, prior to Screening 1 or between Screening 1 and Day 1;
  * Woman of childbearing potential (WOCBP) not willing to adhere to highly effective contraception or strict abstinence for the duration of the trial and for 90 days post completion/discontinuation; and
  * Pregnancy (including a positive urine test) or current breast feeding.

From Screening 2

• Prior probability of undiagnosed endogenous Cushing syndrome based on either of:

* wo morning serum cortisol values after dexamethasone suppression \>5.0 mcg/dL together with plasma dexamethasone \>140 ng/mL; or
* a morning serum cortisol value after dexamethasone suppression \>1.8 mcg/dL, together with plasma dexamethasone \>140 ng/mL and any one of the following that is not attributable to an etiology other than endogenous Cushing's syndrome:
* supraclavicular/dorsocervical fat accumulation;
* irounding of the face (especially compared with prior photos);
* skin changes (violaceous striae, skin thinning, or excessive bruising);
* proximal muscle weakness on exam; or
* history of deep vein thrombosis/pulmonary embolism.
* Plans for, or medically unable to forego, treatment for endogenous Cushing syndrome or ACS within the next 8 months. (For clarity, patients with EnCS or ACS, not having such treatment plans, and medically able to forego treatment for 8 months may enroll if otherwise eligible).
* Severe, poorly controlled hypertension (mean systolic BP \>160 mmHg or mean diastolic BP \>100 mmHg) at Screening 2 or between Screening 2 and Day 1, including by at-home monitoring. (Such patients will be eligible to rescreen for Part 2 when they restore BP \<160/100 mmHg for 1 month on a new stable medication regimen).
* Positive urine screen for recreational drugs (except tetrahydrocannabinol (THC)).
* Glomerular filtration rate (GFR) (determined using Chronic Kidney Disease Epidemiology Collaboration \[CKD-EPI\]) \<45 mL/min/1.73 m².
* Poorly controlled hyperthyroidism/hypothyroidism (confirmed by TSH or Free thyroxine \[fT4\]).
* Liver enzymes \>3 × upper limit of normal (ULN) (alanine aminotransferase (ALT) or aspartate aminotransferase (AST) or bilirubin \>1.5 × ULN.(excepting benign conditions such as Gilbert's)
* Known hypersensitivity to clofutriben or to any of the product