Eprotirome (KB2115)
Eprotirome is a liver-selective thyroid hormone receptor beta agonist developed for dyslipidaemia. It sharply lowered LDL cholesterol in trials but development was halted after cartilage damage appeared in a long-term dog study, ending its clinical path.
01 Overview
Eprotirome was engineered for hepatic uptake and TR-beta selectivity, aiming to reproduce thyroid hormone's cholesterol-lowering benefits without cardiac effects. Phase 2 trials showed substantial LDL and lipoprotein(a) reductions on top of statins, and physique users noted its lipid and mild fat-loss potential.
Development was terminated when a 12-month canine study revealed cartilage damage, and some human trials showed liver enzyme elevations. It never reached approval and exists only as a research/grey-market compound today.
02 Mechanism
Liver-targeted selective agonist of thyroid hormone receptor beta, boosting hepatic LDL-receptor expression, reverse cholesterol transport and lipid oxidation while sparing cardiac TR-alpha.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Trial dosing | 50–200 mcg/day | Oral | Phase 2 dyslipidaemia doses; not approved |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| LDL cholesterol reductionMarked LDL lowering, additive to statin therapy in trials. | -20 to -30% LDL | Clinical | |
| Lipoprotein(a) reductionReduced Lp(a) and triglycerides, an unusual and desirable effect. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Liver enzyme elevationDose-dependent rises in transaminases during treatment. | Moderate | Common in trials | Clinical | |
| Cartilage damage (preclinical)Long-term canine study found cartilage damage, halting development. | Severe | Seen in dogs | Preclinical |