QS-21 (Aquila Biopharmaceuticals)

QS-21 is a purified **Quillaja saponaria** triterpene-saponin fraction used as an immunostimulatory vaccine adjuvant. In the University of Virginia Phase 1 melanoma study NCT00003224, QS-21 was administered subcutaneously as an adjuvant with peptide 946-based melanoma vaccine constructs, with or without tetanus helper peptide; it was not itself the melanoma antigen vaccine. QS-21 is intended to amplify antigen-specific cellular and humoral immune responses rather than directly target melanoma cells. ([clinicaltrials.gov](https://clinicaltrials.gov/study/NCT00003224))

Brand names

Stimulon

Other names

QS21QS-21QS 21Saponin QS-21