Pramlintide
/ Synthetic amylin analog (37-residue, 3 amino-acid substitutions for solubility)ALIAS · Symlin (trade) · Symlinpen · AC-137
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Tier 1. Pramlintide is a synthetic 37-residue analog of human amylin (islet amyloid polypeptide) with three proline substitutions (positions 25, 28, 29) that prevent the aggregation that limits native human amylin solubility. FDA-approved 2005 as a postprandial glucose adjunct to mealtime insulin in type 1 and insulin-using type 2 diabetes, based on Phase 3 trials (Whitehouse 2002 T1DM, Hollander 2003 and Ratner 2004 T2DM).
Pramlintide is a synthetic analog of amylin (islet amyloid polypeptide), the 37-residue peptide co-secreted with insulin from pancreatic beta cells. Native human amylin aggregates and forms islet amyloid; pramlintide substitutes proline at positions 25, 28, and 29 (mimicking rat amylin at these positions) to abolish aggregation while retaining receptor pharmacology. Receptor binding at amylin-receptor heterodimers (calcitonin receptor plus RAMP1/2/3 accessory proteins) in the area postrema slows gastric emptying, suppresses postprandial glucagon secretion, and produces a modest centrally-mediated reduction in food intake. The net postprandial glycemic effect is meaningful when combined with mealtime insulin in insulin-using diabetes.
Tier 1. Whitehouse and colleagues (Diabetes Care 2002) randomised type 1 diabetes participants on insulin to mealtime pramlintide or placebo and reported HbA1c and postprandial glucose improvement. Ratner and colleagues (Diabetes Care 2004) and Hollander and colleagues (Diabetes Care 2003) extended the Phase 3 evidence base into insulin-using type 2 diabetes. Modest HbA1c reduction (0.3 to 0.5 percentage points) and small reductions in body weight have been the consistent findings across the program.
Nausea is the dominant adverse event, generally dose-dependent and tolerance-developing over weeks of administration. Pramlintide carries a US boxed warning for severe insulin-induced hypoglycemia when added to mealtime insulin without insulin dose reduction — the slowed gastric emptying and reduced glucagon counter-regulation amplify hypoglycemia risk if insulin is not down-titrated at initiation. Injection-site reactions and headache are reported.
Regulatory status
- FDA status:
- FDA-approved
- Compounding:
- Not eligible for compounding (approved, not in shortage)
Pramlintide adoption has been limited by the requirement for a separate injection at each meal (it cannot be co-formulated in the same syringe as insulin), the boxed hypoglycemia warning, and the modest absolute glycemic benefit. The development of GLP-1 receptor agonists (semaglutide, tirzepatide) has substantially reduced clinical interest in mealtime pramlintide, though combination amylin/insulin formulations (and dual amylin/GLP-1 agonists in development) continue to receive research attention. Vendor-grade pramlintide is not pharmaceutically equivalent to Symlin.