- Design
- Six phase 1 drug interaction studies
- Population
- Healthy adult volunteers
- Primary outcome
- Orforglipron and probe-drug pharmacokinetics with enzyme and transporter precipitants
- Effect
- Exposure increased with clarithromycin and ciclosporin, decreased with carbamazepine; no meaningful effect on midazolam, digoxin, atorvastatin
Orforglipron is an oral, small-molecule GLP-1 receptor agonist in development for type 2 diabetes and obesity. Unlike peptide GLP-1 drugs, it is cleared through CYP3A4 and transported by OATP1B and P-glycoprotein, so drug interactions matter in a way they do not for injectable agents. Six phase 1 studies in healthy volunteers characterised these.
Orforglipron exposure increased with clarithromycin (a CYP3A4 inhibitor) and ciclosporin (which also inhibits OATP1B), and decreased with carbamazepine (a CYP3A4 inducer). Quinidine (a P-glycoprotein inhibitor) had no meaningful effect. In the other direction, orforglipron did not meaningfully change midazolam, digoxin or atorvastatin, weakly raised rosuvastatin through BCRP inhibition, and raised simvastatin acid, which the authors attribute to simvastatin's own disposition.
The abstract gives the direction of these interactions, not their size. Its regulatory status is not stated here. If it reaches practice, a medication review for a patient taking it will need to look for CYP3A4 inhibitors and inducers.
- Expect higher orforglipron levels with strong CYP3A4 inhibitors such as clarithromycin, and with ciclosporin.
- Expect lower levels with enzyme inducers such as carbamazepine, which may reduce effect.
- Little change is expected for atorvastatin, digoxin or midazolam co-prescribed with orforglipron.
- Watch rosuvastatin and simvastatin tolerability when combined, given the modest rises seen.
Why it matters
An oral small-molecule GLP-1 drug brings cytochrome interactions into a class prescribers have treated as interaction-free.
Don't overread it
Healthy-volunteer studies show direction and mechanism; dose adjustments for patients will depend on the final label.
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