Drug Affinity Complex (DAC)

Also known as: DAC

A Drug Affinity Complex is a modification that binds a peptide to serum albumin to extend its half-life. CJC-1295 with DAC is studied for sustained GHRH-receptor activation.

The DAC is a maleimidopropionic acid group on the peptide that reacts selectively with the free cysteine-34 thiol of circulating serum albumin, forming a covalent bond in situ. Because albumin itself has a long circulating half-life and is large enough to escape rapid renal filtration, tethering the peptide to it markedly slows the peptide’s clearance and proteolytic breakdown.

This distinguishes CJC-1295 with DAC from the unmodified GHRH analog — modified GRF 1-29, also called CJC-1295 without DAC — which is cleared far more quickly. The modification is studied in preclinical pharmacokinetic work as a strategy for sustained GHRH-receptor exposure.