Pasireotide is a novel cyclohexapeptide somatostatin analogue. It binds with high affinity to four of the five somatostatin receptor subtypes.1 Activation of these receptors on ACTH-secreting pituitary tumours inhibits the excessive production of ACTH that leads to the symptoms of Cushing’s disease.
The efficacy and safety of pasireotide in the treatment of Cushing’s disease were assessed in a randomised, double-blind phase III trial (n=162), involving adult patients with urinary-free cortisol (UFC) levels at least 1.5 times the upper limit of normal.2 Pasireotide was administered by subcutaneous injection twice daily. The primary endpoint was normalisation of UFC at six months, defined as a level at or below the upper limit of normal, with no prior dose increase.
After six months, mean UFC levels had normalised in 14.6% (95% CI 7.0–22.3) of patients receiving pasireotide 600 microgram twice daily and in 26.3% (95% CI 16.6–35.9) of those receiving 900 microgram twice daily. The primary endpoint was therefore determined to have been met in the 900 microgram group.1,2
Decreases in blood pressure, BMI and total cholesterol were observed at six months in patients with both full and partial mean UFC control.1
Pasireotide was associated with hyperglycaemia-related adverse events in 73% of patients; other adverse effects were similar to those observed with other somatostatin analogues.2
Novartis is currently undertaking a phase III trial to evaluate a longer-acting form of pasireotide that only requires injection once a month.