Pasireotide

Pasireotide (Signifor/Signifor LAR) is a real, FDA-approved second-generation somatostatin analog, approved separately for Cushing's disease and acromegaly — but its own trial data show only modest efficacy, and its hyperglycemia rate is high enough to be the central practical concern with the drug.

What makes it different from octreotide and lanreotide

Pasireotide is a second-generation cyclohexapeptide somatostatin analog (originally coded SOM230). Where octreotide and lanreotide bind almost exclusively to somatostatin receptor subtype 2 (SSTR2), pasireotide binds with high affinity across SSTR1, 2, 3 and 5. That broader footprint is the specific reason it exists as a separate drug rather than a me-too: corticotroph tumors in Cushing's disease express relatively little SSTR2 but much more SSTR5, so the SSTR2-dominant drugs largely don't work there, while pasireotide's SSTR5 engagement gives it a real mechanistic foothold.

The approvals and what the pivotal trials actually showed

The FDA approved Signifor (twice-daily subcutaneous) on 14 December 2012 for Cushing's disease in adults for whom pituitary surgery isn't an option or hasn't been curative, based on a 162-patient, 12-month Phase 3 trial (Colao et al., N Engl J Med 2012, PMID 22397653). The honest headline figure from that trial: urinary free cortisol normalized in only 26.3% of patients on the 900µg twice-daily dose and 14.6% on the 600µg dose at 6 months — meaning roughly three in four patients on the higher dose had not normalized cortisol by that point. It was approved anyway largely because Cushing's disease had (and still has) very few approved medical options. A separate monthly long-acting formulation, Signifor LAR, was approved 15 December 2014 for acromegaly, supported partly by the PAOLA trial (Gadelha et al., Lancet Diabetes Endocrinol 2014, DOI: 10.1016/S2213-8587(14)70169-X), which found pasireotide LAR produced better biochemical control than continued octreotide or lanreotide in patients inadequately controlled on those drugs — at the cost of a substantially higher rate of hyperglycemia and new diabetes (see below).

The hyperglycemia problem

This is the practical reason pasireotide isn't first-line: across trials, hyperglycemia occurred in roughly 40% of patients, new diabetes in about 18%, and elevated HbA1c in about 11%. Nearly all patients — including those with normal baseline glucose — show worsening glycemic markers within the first two weeks, and the label requires weekly self-monitoring of blood glucose for the first 2-3 months. Other class-typical effects apply too: gallstones, bradycardia/QT effects, and suppression of other pituitary hormones (adrenal insufficiency from cortisol suppression is a specific risk worth monitoring for).

Current status

Still marketed, now by Recordati Rare Diseases (Novartis sold the rights in 2019). No generic identified. No FDA warning letter naming pasireotide as a grey-market "research peptide" was found — its hyperglycemia burden and complete absence of cosmetic or performance appeal make that essentially a non-issue for this drug.