Extend Biopharma

Extend Biosciences is a privately held clinical-stage biotechnology company developing long-acting peptide and protein therapeutics using its proprietary D-VITylation platform. The platform attaches a vitamin D-derived moiety to peptides or proteins to improve half-life, absorption, and bioavailability after subcutaneous administration. Its lead program, EXT608, is a long-acting parathyroid hormone derivative for hypoparathyroidism and has advanced into Phase 2 clinical testing. The company is also developing EXT418, a long-acting ghrelin-based candidate for diabetes-induced peripheral neuropathy, and has reported preclinical work in cancer cachexia. Overall, the company is positioned as a platform-enabled rare disease and peptide therapeutics developer rather than a broad commercial pharma company.