Pegulicianine
Pegulicianine, sold under the brand name Lumisight, is an optical imaging agent. It is given via intravenous injection.
Pegulicianine was approved for medical use in the United States in April 2024. The US Food and Drug Administration considers it to be a first-in-class medication.
Medical uses
Pegulicianine is indicated for fluorescence imaging in adults with breast cancer as an adjunct for the intraoperative detection of cancerous tissue within the resection cavity following removal of the primary specimen during lumpectomy surgery.Mechanism of action
Pegulicianine is non-fluorescent in its intact parent form. However, in breast cancer tissue, where cathepsins and matrix metalloproteinases are overexpressed, it is enzymatically cleaved into two fragments, one of which is fluorescent.Pegulicianine consists of the following four components that are covalently linked to each other:
- A far-red cyanine dye known as Cy5, which has a peak absorption near 650 nm and emission around 675 nm, allowing detection by imaging systems.
- A non-fluorescent chromophore called QSY21, which functions as a fluorescence quencher. QSY21 absorbs the emission from Cy5, suppressing fluorescence until enzymatic cleavage occurs.
- A tripeptide linker, which is cleaved by tumor-associated proteases. Once cleaved, Cy5 is released from proximity to QSY21, restoring its fluorescence.
- A polyethylene glycol side chain that enhances water solubility, protects the molecule from enzymatic degradation, extends circulation time by increasing its hydrodynamic radius—thereby reducing renal clearance—and lowers immunogenicity.