Osilodrostat normalizes urinary free cortisol in Cushing’s disease for most at 72 weeks
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More than 80% of adults with Cushing’s disease receiving osilodrostat had normalized mean urinary free cortisol levels at 72 weeks of treatment, according to findings from the LINC 3 study extension.
“Cushing’s disease is a chronic condition, and many patients require prolonged pharmacological treatment. Therefore, evaluating long-term efficacy and safety of drug therapies in clinical trials is essential,” Maria Fleseriu, MD, FACE, professor of medicine and neurological surgery and director of the Pituitary Center at Oregon Health & Science University in Portland and a Healio | Endocrine Today co-editor, told Healio. “Our findings build on the positive results of the LINC 3 study core phase, and it was reassuring to see that continued treatment with osilodrostat for over 72 weeks provided long-term normalization of cortisol levels. Furthermore, continued treatment with osilodrostat also led to sustained improvements in clinical signs and physical manifestations of hypercortisolism, as well as health-related quality of life, which are all important factors in the management of these patients.”
Fleseriu and colleagues enrolled 106 adults with Cushing’s disease who were responders to osilodrostat (Isturisa, Recordati) at 48 weeks during the LINC 3 core study to enter the extension phase of the trial. Participants continued to receive open-label osilodrostat until 72 weeks or treatment discontinuation. Mean urinary free cortisol was collected every 12 weeks. Physical manifestations of hypercortisolism were rated at 48 and 72 weeks. Participants completed the Cushing’s Quality of Life questionnaire and Beck Depression Inventory II at 48 and 72 weeks. Adults were deemed to have completely responded to treatment if mean urinary free cortisol was less than the upper limit of normal and partially responded to treatment if mean urinary free cortisol was above the upper limit of normal but decreased more than 50% from baseline.
The findings were published in the European Journal of Endocrinology.
Of the 106 participants in the extension study, 98 completed 72 weeks of treatment. At 72 weeks, 81.1% of participants were complete responders to treatment, and reductions in mean urinary free cortisol from the core phase were maintained during the extension.
Improvements in most cardiovascular and metabolic-related parameters from the core study were maintained or improved in the extension phase. The cohort also had increases in quality of life score and improvements in Beck Depression Inventory II scores.
The proportion of participants with improvements in physical manifestation of hypercortisolism were maintained or improved in all areas at 72 weeks. For hirsutism in women, 86.4% had an improved or stable severe score at 72 weeks. Improved scores were observed in participants with mild, moderate and severe physical manifestations at baseline with few adults experiencing worse manifestations at the end of the extension study.
There were no new safety signals reported in the extension study. Of the extension study participants, 11.3% discontinued osilodrostat due to adverse events, a similar percentage to the 10.9% discontinuation rate during the core phase of the study.
Several hormone concentrations, including mean adrenocorticotropic hormone, 11-deoxycortisol and plasma aldosterone, stabilized during the extension phase after changes were observed in the core study compared with baseline. Mean testosterone in women decreased from 2.6 nmol/L at 48 weeks to 2.1 nmol/L at 72 weeks. There were no changes observed in mean testosterone levels for men.
“Patients should be regularly monitored and osilodrostat dose titrated as necessary, alongside adjustment of concomitant medications, to optimize outcomes,” the researchers wrote. “Taken together, these findings support osilodrostat as an effective and well-tolerated long-term treatment option for patients with Cushing’s disease.”
For more information:
Maria Fleseriu, MD, FACE, can be reached at fleseriu@ohsu.edu.