Degboé Y, Sunzini F, Sood S, et al. - Given that psoriatic arthritis (PsA) is correlated with bone erosion and inflammation-induced bone loss, which are mediated by osteoclasts and modulated by inflammatory cytokines, experts aspired to explore whether and how apremilast (a selective phosphodiesterase 4 inhibitor) affects osteoclast formation in humans. In the presence and absence of apremilast, osteoclastogenic cytokine production by activated human peripheral blood mononuclear cells was measured. Apremilast targets phosphodiesterase-4, which not only inhibits osteoclastogenic cytokine production but also directly suppresses inflammation-driven osteoclastogenesis. Such results indicate that apremilast could have the potential to have a direct bone-protective effect in patients with PsA.