PI3K-IN-6 (compound 20a) is an oral active and highly selective phosphoinositide 3-kinase ( PI3K ) β/δ inhibitor, with IC 50 values of 7.8 nM/5.3 nM for PI3K β/δ, respectively. PI3K-IN-6 (compound 20a) has potential top treat phosphatase and tensin homolog ( PTEN ) feficient tumors.