Osilodrostat is associated with rapid normalization of mean urinary free cortisol (mUFC) excretion in patients with Cushing disease and has a favorable safety profile, according to the results of a study published in the Journal of Clinical Endocrinology & Metabolism.
The phase 3 LINC-4 study (ClinicalTrials.gov Identifier: NCT02697734) evaluated the safety and efficacy of osilodrostat, a potent, orally available 11β-hydroxylase inhibitor, compared with placebo in patients with Cushing disease.
The trial, which was conducted at 40 centers in 14 countries, included a 12-week, randomized, double-blind, placebo-controlled period that was followed by a 36-week, open-label osilodrostat treatment period with an optional extension.
Eligible patients were aged 18 to 75 years with a confirmed diagnosis of persistent or recurrent Cushing disease after pituitary surgery and/or irradiation or de novo disease, as well as an mUFC level greater than 1.3 times the upper limit of normal (ULN). The patients were randomly assigned 2:1 to osilodrostat 2 mg twice daily or matching placebo, stratified by prior pituitary irradiation.
The primary endpoint was the proportion of patients who achieved mUFC ≤ULN at week 12. The key secondary endpoint was the proportion of patients who achieved mUFC ≤ULN at week 36.
A total of 73 patients (median age, 39.0 years; 83.6% women) were randomly assigned to either osilodrostat (n=48) or placebo (n=25) and received at least 1 study drug dose from November 2016 to March 2019.
The participants had a median (interquartile range [IQR]) time since diagnosis of Cushing disease of 67.4 (26.4-93.8) months. The median treatment duration in the randomized, placebo-controlled period was 12.0 weeks in both the osilodrostat group (IQR, 2.0-13.0 weeks) and the placebo group (IQR, 11.7-13.7 weeks).
The proportion of patients who achieved mUFC ≤ULN (≤138 nmol/24 h) at week 12 was significantly increased in those who received osilodrostat (n=37, 77.1%) vs those who received placebo (n=2, 8.0%), with an estimated odds ratio of 43.4 (95% CI, 7.1-343.2) in favor of osilodrostat (P <.0001).
A total of 59 patients (80.8%; 95% CI, 69.9-89.1) also achieved the key secondary endpoint of mUFC ≤ULN at week 36, after 24 weeks of open-label osilodrostat.
The most frequently occurring adverse events in the placebo-controlled period in the osilodrostat and placebo groups, respectively, were decreased appetite (37.5% vs 16.0%), arthralgia (35.4% vs 8.0%), nausea (31.3% vs 12.0%), and fatigue (25.0% vs 16.0%).
A potential study limitation is that although osilodrostat exposure was greater than 1 year among the participants, some adverse effects may take longer to be observed.
“This randomized, placebo-controlled trial demonstrates that osilodrostat is a highly effective treatment for Cushing disease, normalizing UFC excretion in 77% of patients after 12 weeks’ treatment,” stated the investigators. “Cortisol reductions were maintained throughout 48 weeks of treatment and were accompanied by improvements in clinical signs of hypercortisolism and quality of life. The safety profile was favorable.”
Disclosure: This study was funded by Novartis Pharma AG. Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Gadelha M, Bex M, Feelders RA, et al. Randomized trial of osilodrostat for the treatment of Cushing’s disease. J Clin Endocrinol Metab. Published online March 23, 2022. doi:10.1210/clinem/dgac178