Orforglipron interactions: CYP3A4 and OATP1B matter

Design

Six phase 1 drug-interaction studies

Population

Healthy volunteers

Primary outcome

Orforglipron and probe-drug exposure with enzyme and transporter modulators

Effect

Exposure rose with clarithromycin and ciclosporin, fell with carbamazepine

Orforglipron is an oral non-peptide GLP-1 receptor agonist in development for type 2 diabetes and obesity. It is a substrate of CYP3A4, OATP1B transporters and P-glycoprotein. Six phase 1 studies in healthy volunteers tested it with standard interacting drugs.

Clarithromycin and ciclosporin increased orforglipron exposure, and carbamazepine reduced it; quinidine had little effect. In the other direction, orforglipron had no clinically meaningful effect on midazolam, digoxin or atorvastatin. A weak rise in rosuvastatin was consistent with BCRP inhibition, and a rise in simvastatin acid reflected that statin's own handling rather than enzyme inhibition.

If orforglipron is approved, the interactions to plan around are strong CYP3A4 inhibitors and inducers and OATP1B inhibitors such as ciclosporin. The abstract does not give the size of each change, so dose advice will depend on the eventual label.

• Expect higher orforglipron levels with clarithromycin or ciclosporin.
• Expect lower levels with enzyme inducers such as carbamazepine.
• Orforglipron is unlikely to alter levels of midazolam, digoxin or atorvastatin.
• Monitor for statin side effects if rosuvastatin is co-prescribed, though the rise was weak.

Why it matters

Unlike injectable GLP-1 agonists, an oral small molecule brings classic enzyme-based interactions.

Don't overread it

These are healthy-volunteer studies; the drug's label will set the actual dose advice.

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