Bicyclic heterocyclic derivatives as mnk1 and mnk2 modulators and uses thereof

A compound of Formula (Ia):

• or a pharmaceutically acceptable form thereof, wherein
• X1, X2, and X3 are independently N or C;
• X4 and X5 are independently N or CR4;
• wherein at least one of X1, X2, X3, X4, and X5 is N;
• X7 is N or CR10;
• X8 is N or CR11;
• is a single or double bond, as valency allows;
• R1 is an optionally substituted aryl, optionally substituted carbocyclyl, optionally substituted heteroaryl, optionally substituted heterocyclyl, —CN, —SR, —N(R)2, —C(O)R, —CO2R, —C(O)N(R)2, —C(O)NROR, —S(O)R, —SO2R, —SO2N(R)2, —OC(O)R, —NRC(O)R, —NRSO2R, or —NRC(O)N(R)2;
• each R is independently hydrogen, optionally substituted C1-6 aliphatic, optionally substituted aryl, optionally substituted carbocyclyl, optionally substituted heteroaryl, or optionally substituted heterocyclyl;
• or two R groups on the same nitrogen may be taken together to form an optionally substituted heterocycle;
• R2, R3, R5, R6, R7, R8, R9, R10, and R11 are independently hydrogen, halogen, optionally substituted aliphatic, optionally substituted aryl, optionally substituted carbocyclyl, optionally substituted heteroaryl, optionally substituted heterocyclyl, —CN, —OR, —SR, —N(R)2, —NO2, —C(O)R, —CO2R, —C(O)N(R)2, —C(O)NROR, —S(O)R, —SO2R, —SO2N(R)2, —OC(O)R, —NRC(O)R, —NRSO2R, or —NRC(O)N(R)2;
• each R is independently hydrogen, optionally substituted C1-6 aliphatic, optionally substituted aryl, optionally substituted carbocyclyl, optionally substituted heteroaryl, or optionally substituted heterocyclyl;
• or two R groups on the same nitrogen may be taken together to form an optionally substituted heterocycle;
• each R4 is independently hydrogen, halogen, or optionally substituted C1-6 aliphatic;
• and R1 and R2, R2 and R3, R3 and R4, R1 and R11, R10 and R11, R5 and R6, R6 and R7, R7 and R8, or R8 and R9 may be optionally taken together to form an optionally substituted 5-6 membered carbocyclic, aryl, heterocyclic, or heteroaryl ring.