Stability of Multi-Peptide Vaccines in Conditions Enabling Accessibility in Limited Resource Settings

We have previously shown that lyophilized mixtures of six- and twelve-melanoma peptide vaccines retain stability, purity, and amino acid sequence identity for up to five years when stored at -80 °C. However, this temperature requirement presents a significant obstacle to storage and distribution of vaccines for low-resource environments. Thus, we examined the stability of these peptides over a range of temperatures for varying durations of time. When stored at +4 °C or at room temperature for up to three months, 17 of the 18 peptides remained stable. The only change for the remaining peptide was an increase in an oxidized methionine residue. The results presented in this report support broadening the accessibility of these and other peptide-based vaccines to resources-limited communities.