Prospective study of metyrapone in endogenous Cushing's syndrome (PROMPT)
An erratum to this article was published (Eur J Endocrinol, 28 Aug 2026 ↗)
Authors' conclusion
Metyrapone is a safe and effective treatment for endogenous CS.
Study context
- Population
- Adults with endogenous Cushing's syndrome (CS) (unsuitable for or uncontrolled after surgery) and 3 urinary free cortisol (UFC) concentrations each ≥1.5-fold upper limit of normal (ULN)49 evaluable
- Participants
- 50 adults
- Outcome
- Normalization of mUFC
- Follow-up
- Week 12
Methodological detailsinternational, open-label
- International
- Open-label
Main finding
As reported in the abstract
Primary endpoint met (mUFC normalization), % of participants
46.9% (95% CI 32.5%-61.7%) (95% CI)
Observational data: associations, not effects.
Further findings
Normalization of mUFC · week 24
- Efficacy maintained, % of participants
- 52.5%; 95% CI 37.5%-67.1% (95% CI)
- 40 evaluated at week 24
Normalization of mUFC · week 36
- Efficacy maintained, % of participants
- 48.6%; 95% CI 33.0%-64.4% (95% CI)
- 35 evaluated at week 36
Responders (normalization or ≥50% decrease of baseline mUFC) · weeks 12, 24 and 36
- Responder rate, week 12
- 80.9%
- Responder rate, week 24
- 77.5%
- Responder rate, week 36
- 71.4%
Clinical features and quality of life (QoL)
- Clinical features and QoL improved
Safety
- Mild-to-moderate adverse events (AEs), mostly during first 12 weeks
- 47 (94%)
- Nausea
- 38%
- Fatigue
- 26%
- Headache
- 22%
- Severe AEs
- 8
- Reversible adrenal insufficiency during titration
- 6
Parts of this Brief are withheld: the automatic checks could not confirm them against the abstract.
Original publication
Prospective study of metyrapone in endogenous Cushing's syndrome (PROMPT). Eur J Endocrinol. Published 12 September 2025. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →