SynAct is developing selective melanocortin therapeutics to address inflammatory and autoimmune diseases characterized by excessive or chronic inflammation. SynAct’s lead drug candidate, resomelagon (AP1189), is an oral selective melanocortin agonist that was designed to stimulate MC1R and MC3R, but not MC2R, to help resolve excessive inflammation without side effects related to cortisol release. Resomelagon (AP1189) is a biased agonist that activates one of two main signal transduction pathways and avoids cAMP signaling through MC1R, which has been associated with unwanted skin hyperpigmentation.

The lead peptide agonist is TXP-11. This peptide shows the highest potency to the MC1R and MC3R, like resomelagon (AP1189). Where resomelagon (AP1189) is designed for once-daily oral administration, TXP-11 is designed for intravenous administration in complicated surgeries to prevent organ dysfunction and failure and for other hyperimmune responses treated in the acute care setting.