Long-acting pasireotide provides ‘sustained biochemical improvements’ in Cushing’s disease
For patients with persistent or recurring Cushing’s disease, monthly pasireotide therapy was safe and effective, leading to normal urinary free cortisol levels in 47% of patients after 2 years, according to findings published in Clinical Endocrinology.
“The management of Cushing’s syndrome, and particularly Cushing’s disease, remains challenging,” Maria Fleseriu, MD, FACE, professor of neurological surgery and professor of medicine in the division of endocrinology, diabetes and clinical nutrition in the School of Medicine at Oregon Health & Science University and director of the OHSU Northwest Pituitary Center, told Endocrine Today. “Long-acting pasireotide provided sustained biochemical improvements and clinical benefit in a significant proportion of patients with Cushing’s disease who elected to continue in this extension study. There were many adverse events reported overall, but no new safety signals emerging over long-term treatment.”
In the last decade, medical treatment for Cushing’s disease has progressed from a few steroidogenesis inhibitors to three novel drug groups: new inhibitors for steroidogenic enzymes with possibly fewer adverse effects, pituitary-directed drugs that aim to inhibit the pathophysiological pathways of Cushing’s disease, and glucocorticoid receptor antagonists that block cortisol’s action, Fleseriu, who is also an Endocrine Today Editorial Board member, said.
In an open-label extension study, Fleseriu and colleagues analyzed data from 81 adults with confirmed Cushing’s disease with mean urinary free cortisol not exceeding the upper limit of normal, who transitioned from a 12-month, randomized controlled trial where they were assigned 10 mg or 30 mg once-monthly intramuscular pasireotide (Signifor LAR, Novartis). During the main study, researchers recruited participants with mean urinary free cortisol level concentration 1.5 to five times the upper limit of normal, normal or greater than normal plasma and confirmed pituitary source of Cushing’s disease. Participants who elected to continue in the extension were considered biochemical responders or benefited from the study drug per the clinical investigator, Fleseriu said.
“As in all extension studies, the bias is inherent that patients deemed responders tend to continue, but for any type of treatment for pituitary tumors, and particularly Cushing’s disease, long-term, robust data on efficacy and safety parameters is essential,” Fleseriu said.
Median overall exposure to pasireotide at the end of the extension study was 23.9 months, with nearly half of patients receiving at least 1 year of treatment during the extension phase. Researchers found that improvements in clinical signs of hypercortisolism were sustained throughout the study and median urinary free cortisol remained within normal range. Overall, 38 participants (47%) had controlled urinary free cortisol at month 24 (after 12 months of treatment during the extension phase), with researchers noting that the proportion of participants with controlled or partially controlled urinary free cortisol was stable throughout the extension phase.
“Interestingly, the median salivary cortisol level decreased but remained above normal (1.3 times upper limit of normal) at 3 years,” Fleseriu said.
As seen in other pasireotide studies, and expected based on the mechanism of action, researchers observed hyperglycemia-related adverse events in 39.5% of participants, with diabetes medications initiated or escalated in some patients, Fleseriu said. However, mean fasting glucose and HbA1c were stable during the extension phase, after increasing in the main study. Within the cohort, 81.5% had type 2 diabetes at baseline (entering extension phase) and 88.9% patients had type 2 diabetes at last assessment.
“Pasireotide acts at the tumor level, and tumor shrinkage is seen in many patients,” Fleseriu said. “In this study, 42% and 32.1% had a measurable microadenoma or macroadenoma, respectively, on MRI at the start of pasireotide treatment; an adenoma was not visible in almost a quarter of patients at 2 years.”
Among patients with a measurable adenoma at baseline and at month 24 (n = 35), 85.7% experienced a reduction of at least 20% or a 20% change in tumor volume between the two time points. Improvements in median systolic and diastolic blood pressure, BMI and waist circumference were sustained during the extension, Fleseriu said.
“The long-term safety profile of pasireotide was favorable and consistent with that reported during the first 12 months of treatment,” the researchers wrote. “These data support the use of long-acting pasireotide as an effective long-term treatment option for some patients with [Cushing’s disease].”
Fleseriu said individualized treatment selecting patients who will derive benefit from therapy will be crucial, balancing both efficacy and the potential risks and costs. – by Regina Schaffer
Disclosures: Fleseriu reports she has received consultant fees and her institution has received research support from Novo Nordisk and Pfizer. Please see the study for all other authors’ relevant financial disclosures.