Safety, Tolerability, and Pharmacokinetics of Mufemilast, a PDE4 Inhibitor, in Healthy Participants: A First-in-Human...

Phosphodiesterase 4 (PDE4) is a branch of the phosphodiesterase isoenzyme family and plays a crucial role in maintaining intracellular cAMP homeostasis. Mufemilast, a novel PDE4 inhibitor, has demonstrated anti-inflammatory effects in preclinical studies and holds promise for treating inflammatory diseases. The pharmacokinetics, safety, and tolerability profiles of mufemilast were evaluated in healthy participants. In the single ascending dose study, 68 healthy male subjects were randomized to receive single oral doses of mufemilast ranging from 10 to 125 mg. In the multiple ascending dose study, 24 healthy subjects received mufemilast at doses of 15, 30, and 60 mg twice daily for 7 consecutive days. In the two-period, crossover food effect study, 12 healthy subjects were administered a 52.5-mg dose of mufemilast both in the fasted and fed state. The results showed that mufemilast was rapidly absorbed and the exposure increased with dose. Following multiple doses, the mean accumulation ratios indicated some accumulations of mufemilast. The T_max was 3 and 5 h under fasted and fed conditions, while the geometric mean ratio and 90% CIs for AUC_last, AUC_inf, and C_max were 105.76 [92.69%,120.66%], 105.60 [92.52%,120.52%], and 92.85 [78.60%,109.68%], respectively. Most AEs were grade 1 or 2, with positive occult blood test as the most common. Mufemilast was safe and tolerated by healthy participants across all dose groups (10-125 mg). PK analysis revealed that mufemilast exhibited linear PK characteristics. These results support the further evaluation of its efficacy.