Cyclic Peptide Delivery System Makes Oral Insulin Viable
Kumamoto University's DNP cyclic peptide system achieved roughly one-third to nearly half the effectiveness of injected insulin in animal studies — a major advance for oral insulin delivery.
#Cyclic Peptide
21 stories
Cyclic peptides — including macrocyclic and bicyclic forms — are the structural class behind much of the modern undruggable-target peptide pipeline. Cyclization confers stability against proteases, improved membrane permeability, and stricter conformational lock that often translates to higher binding affinity.
The commercial dimension matters too. Apellis Pharmaceuticals' pegcetacoplan (EMPAVELI for PNH and C3 glomerulopathy; SYFOVRE for geographic atrophy) is a pegylated cyclic 13-amino-acid complement C3 inhibitor that did $689M in 2025 net product revenue and was the centerpiece of Biogen's $5.6B acquisition completed May 14, 2026. Lutathera (lutetium-177 dotatate), approved in the U.S. and EU, and Pepaxti (melflufen), authorized in the EU after the FDA withdrew its U.S. approval in 2024, round out the approved cyclic-peptide and peptide-drug-conjugate corner of the commercial market.
Covered here: AACR 2026 readouts on cyclic peptides hitting intracellular targets, the University of Utah PapB radical-SAM thioether cyclization paper suggesting a route to GLP-1-like cyclic peptides without traditional medicinal chemistry, biocatalysis platforms based on peptide asparaginyl ligase (PAL), and the AI-design platforms generating cyclic candidates for KRAS and beta-catenin. Stories here cover the chemistry, the discovery platforms, M&A around the modality, and the early-stage clinical work. See #macrocyclic-peptide, #bicyclic-peptide, #pegcetacoplan, and #parabilis-medicines for adjacent threads.
New Cyclic Peptide Could Replace Insulin Injections With Daily Pills
Kumamoto University researchers developed cyclic peptide D-DNP-V that escorts insulin through the gut, achieving one-third to nearly half the effectiveness of injected insulin in mice.
Cyclic Peptide Platform Enables Oral Insulin With 33-41% Bioavailability
Kumamoto University researchers developed a cyclic peptide (DNP peptide) that enables oral insulin delivery through the intestinal wall — a dramatic improvement that could end the century-long dependence on injections.