Metopirone Safely Normalized, or Significantly Lowered, Urine Cortisol Levels in Phase 3/4 Trial

Metopirone (metyrapone) safely normalized, or at least lowered by half, the levels of cortisol found in the urine of patients with endogenous Cushing’s syndrome, according to data from a Phase 3/4 clinical trial.

Findings from the study, called PROMPT (NCT02297945), were presented recently by HRA Pharma Rare Diseases, the therapy’s manufacturer, at the e-ECE conference 2020.

Metopirone is an oral medication that blocks the activity of an enzyme called 11beta-hydroxylase, which is needed for the production of cortisol, the glucocorticoid hormone that is overly produced by the adrenal glands in patients with endogenous Cushing’s.

The medication is approved in Europe for treating endogenous Cushing’s, based on data from observational and retrospective studies published more than 50 years ago.

Although these studies showed Metopirone was effective at lowering the levels of cortisol to a normal range within a short period of time, no prospective study assessing its safety and efficacy had been conducted yet.

Retrospective studies “look backward,” attempting to correlate observed outcomes with other factors, while prospective studies “look forward,” intending to evaluate the outcomes resulting from a known disease or condition.

Now, HRA Pharma reported the first findings of PROMPT, the first prospective study to evaluate the safety and effectiveness of Metopirone in a group of patients with endogenous Cushing’s in a real-life setting.

PROMPT enrolled 50 patients with endogenous Cushing’s who were treated with capsules containing 250 mg of Metopirone for up to 36 weeks (nine months).

Patients whose levels of cortisol in the urine measured over a period of 24 hours exceeded the upper limit of the normal range (165 nmol/24h, or 165 nanomoles per 24 hours)) by at least 50% (measured three times), received treatment for at least 12 weeks (three months). Those whose urine cortisol levels nearly or completely normalized after three months of treatment were eligible to enter in the study’s six-month extension period.

The study’s main goal was to assess the proportion of patients whose cortisol levels in the urine normalized within the first 12 weeks of treatment. Secondary goals included assessing the percentage of patients whose cortisol levels dropped by at least 50% by the end of the first 12 weeks of treatment with Metopirone.

Data from the first 12 weeks of PROMPT showed that Metopirone was able to normalize, or at least lower by half, the levels of cortisol found in the urine of 80% of the patients. This also was accompanied by improvements in patients’ quality of life, other clinical features of Cushing’s, and associated comorbidities.

Treatment also was determined to be safe and well-tolerated.

 “We are thrilled to announce that this first prospective study is confirming that metyrapone is both an effective and safe way to treat endogenous Cushing’s Syndrome — with a significant reduction or normalization of mUFC [mean urinary free cortisol] levels after 12 weeks of treatment,” Frederique Welgryn, managing director of HRA Pharma Rare Diseases, said in a press release emailed to Cushing’s Disease News.

Full data from PROMPT, including its optional six-month extension, will be published next year.

“Rare diseases are an important part of the HRA Pharma portfolio. The PROMPT study is another piece of evidence demonstrating the commitment of HRA Pharma in making effective, safe and affordable treatments for patients with rare diseases,” added David Wright, CEO of HRA Pharma.