AGAMREE (vamorolone)

June 30, 2026: Catalyst Pharmaceuticals, Inc. (NASDAQ: CPRX) reported topline results from a two-part Phase 1 study of vamorolone in healthy adult volunteers assessing cortisol suppression, anti-inflammatory activity, and immunosuppressive effects at clinical and supratherapeutic doses.

Part A (equipotency vs. deflazacort): In a randomized, single-center, crossover study (n=24), single doses of vamorolone 300 mg and deflazacort 0.9 mg/kg showed similar onset (about 2–4 hours post-dose) and comparable cortisol suppression at clinical doses, with expected glucocorticoid receptor activity. Vamorolone showed less pronounced immunosuppressive biomarker effects than deflazacort. The company said these findings support current labeled vamorolone dosing in DMD and suggest no special dosing considerations when switching from deflazacort.

Part B (ascending-dose immunosuppression): In 36 volunteers dosed once daily for seven days (9, 27, or 40 mg/kg), clinically relevant immunosuppressive effects were observed only at 40 mg/kg/day; no relevant immunosuppressive effects were seen at 9 or 27 mg/kg/day. Effects at 40 mg/kg/day increased with repeated dosing and persisted after dosing stopped. The company stated these data suggest meaningful immunosuppression is unlikely at clinically relevant doses and may support lifecycle expansion into other chronic inflammatory rare diseases.