Eganelisib (IPI-549) is an inhibitor of PI3Kγ (IC50 = 16, 3,200, 3,500, and >8,400 nM for PI3Kγ, PI3Kα, PI3Kβ, and PI3Kδ, respectively)

PI3Kβ:3.5 μM, PI3Kα:3.2 μM, PI3Kγ:16 nM

IPI-549 sensitizes doxorubicin-resistant SW620/Ad300 cells to P-glycoprotein (P-gp) substrates, such as paclitaxel (IC50s = 710 and 6.7 nM for paclitaxel alone and in combination with IPI-549, respectively), and increases the level of intracellular paclitaxel in SW620/Ad300 cells[1].

IPI-549 demonstrates favorable pharmacokinetic properties and robust inhibition of PI3K-γ mediated neutrophil migration in vivo[2].

SW620 (4 X 10^6 ) and SW620/Ad300 (5 X 10^6 ) cells were injected subcutaneously at the flank near the armpits of athymic nude mice.?When the subcutaneous tumors were approximately 0.5 x 0.5 cm in size (day 0), the mice were randomized into four treatment groups.?The vehicle used to deliver the IPI-549 and paclitaxel by intraperitoneal (i.p.) injection was ethanol/Cremophor ELP/saline (10%/10%/80%).?Group one received the vehicle only;?group two received vehicle plus 3 mg/kg IPI-549;?group three received vehicle plus 15 mg/kg paclitaxel;?group four, the combination group, received vehicle plus 3 mg/kg IPI-549 one h prior to administration of vehicle plus 15 mg/kg paclitaxel.?The drug doses were administered every 3 days with a total of 4 doses.?Tumor volume was measured using calipers, and body weights were recorded prior to each dosing.