C21, also known as VP01 or "Compound 21," is an agonist of the AT2 receptor currently in development by Vicore Pharma. C21 is being trialed as a drug to treat COVID-19.
C21 is an oral, small molecule drug. C21's CAS # is 477775-14-7.
Clinical trials for COVID-19
The first clinical trial of C21 for COVID-19 began on July 21, 2020. It was a randomized, placebo-controlled multi-center double-blind trial of C21 in hospitalized COVID-19 patients. The primary endpoint of the trial was reduction in CRP. The trial did not show its primary outcome of CRP reduction but showed promising post hoc results in reduction of need for supplemental oxygen:
"..there was no significant group difference in reduction of CRP, 81% and 78% in the C21 and placebo groups, respectively, with a treatment effect ratio of 0.85 [90% CI 0.57, 1.26]. ..A post hoc analysis showed that at day 14, the proportion of patients not requiring supplemental oxygen was 98% and 80% in the C21 group compared to placebo (OR 12.5 [90% CI 2.9, 126]). Fewer patients required mechanical ventilation (one C21 patient; four placebo patients), and C21 was associated with a numerical reduction in the mortality rate (one vs three in the C21 and placebo group, respectively). Treatment with C21 was safe and well tolerated."
On September 17th, 2021, Vicore Pharma announced the dosing of their first patients in a Phase 3 study of C21 for COVID-19. The Phase 3 study is known as "ATTRACT-3" and has as its primary outcome the proportion of subjects discharged from hospital and free of supplemental oxygen.
- List of COVID-19 ARB trials - page collecting information on trials of renin-angiotensin system modulating drugs for COVID-19.