PI3K inhibitor idelalisib efficacious in patients with CLL and indolent NHL.

Investigated whether PI3Kδ isoform expressed in progenitor cells from MF patients, and also evaluated inhibitory effects of idelalisib on cell lines and primary cells from MF patients.

Used CD34+ cells from the peripheral blood of MF patients as well as cell lines and then incubated with idelalisib.

Predominant PKI isoform δ-isoform; PI3Kβ expressed at lower levels and no PI3Kα or γ detected.

Treatment of BaF3/MPL cells with idelalisib decreased the levels of p-AKT by 51%, 64% and 67%, with 0.1, 1.0, 2.0 µM , respectively, when compared to idelalisib-untreated cells.

PI3K-δ predominant isoform expressed in CD34+ cells from MF patients.

In both cell lines, idelalisib inhibits the PI3K/AKT pathway.