Varespladib (LY315920) is a potent and selective group IIA, secretory phospholipase A₂ (sPLA₂) inhibitor with an IC₅₀ of 9 nM. Varespladib exhibits the significant inhibitory effect on sPLA2 activity in serum from various species including rat, rabbit, guinea pig and human with IC₅₀s of 8.1 nM, 5.0 nM, 3.2 nM and 6.2 nM, respectively^[1]. In Vitro: Varespladib (10 μM; 24 and 48 hours; HCjE cells) treatment results in complete inhibition of the RA-induced increase in MUC16 protein detected in cell lysates at both time points^[2].
Varespladib (10 μM; 24 and 48 hours; HCjE cells) treatment significantly inhibits RA-induced MUC16 expression by 100% at 24 hours and 99% at 48 hours^[2]. In Vivo: Varespladib treatment inhibits human sPLA₂-induced release of thromboxane A₂ (TXA₂) from isolated guinea pig lung bronchoalveolar lavage cells with an IC₅₀ of 0.79 μM. And the ED₅₀ for Varespladib is 16.1 mg/kg^[1].