Two lab peptides flip a heart-cell calcium switch in opposite directions in mice; HHS peptide policy: why a purity number alone no longer counts as a full COA. Updated daily.
Nature Cardiovascular Research published a study on 27 October 2026 from Albert Einstein College of Medicine, Thomas Jefferson University, Emory University and the University of Manitoba on mitofusins, proteins on the mitochondrial surface. The team used two cell-permeable peptides that change mitofusin shape in opposite ways. The activator brought the endoplasmic/sarcoplasmic reticulum and mitochondria closer, increased calcium transfer and enlarged infarct size in mice; this depended on mitofusin 2, not mitofusin 1, and on the mitochondrial calcium uniporter. The inhibitor reduced calcium transfer and infarct size in mice, even when given only after reperfusion began. The effects were independent of mitochondrial fusion. These are preclinical results only.
The HHS draft enforcement discretion policy for 503A compounding with six peptide bulk drug substances (FR Doc. 2026-22192, published 30 October 2026) lists in Appendix B what a certificate of analysis must contain; Drug Topics noted on 29 October that a purity percentage alone would be insufficient. The list includes the original manufacturer's name, FDA Establishment Identifier and address, batch number, synthesis, release and expiry dates, identity confirmed by at least two independent orthogonal methods, impurity, residual solvent, elemental impurity and endotoxin results, and a dated signature from the quality unit. A registered distributor or repacker does not replace registration of the original manufacturer. The policy covers compounding for patients only, is interim, non-binding and not an FDA approval. Comments close on 13 November 2026.
For research-community awareness only. Not legal advice.
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A lipid-tailed ring peptide jams the COVID spike and improved survival in mice
Photo: Image: BioLabs Research
Nature Communications published a study on 28 October 2026 from Shionogi and Hokkaido University describing S-880008, a lipid-modified macrocyclic peptide found through mRNA display screening and then structurally optimised as a SARS-CoV-2 fusion inhibitor. In lab tests it was active against diverse variants, including Omicron lineages. Cryo-electron microscopy showed an unusual dual-binding mechanism: the ring portion anchors a conserved, normally hidden site between the receptor-binding domain and subdomain 1, while the lipid chain reaches into the neighbouring protomer. Together they hold the spike in an all-up conformation, stopping the protomers from separating and blocking fusion. In a mouse infection model it reduced viral titers and improved survival. These are preclinical results only.
Regulations.gov opened docket HHS-OASH-2026-0496 on 30 October 2026 for the HHS draft enforcement discretion policy on 503A compounding with six peptide bulk drug substances, published the same day in the Federal Register (FR Doc. 2026-22192, 91 FR 68526). The docket lists a comment deadline of 11:59 p.m. Eastern on 13 November 2026 and does not accept late comments. HHS files it as a nonrulemaking docket: comments go into a record FDA may consider in future 503A bulks list rulemaking, and they are not a vote. No public comments were posted when we checked on the evening of 30 October. The policy stays interim, non-binding and is not an FDA approval.
For research-community awareness only. Not legal advice.
