Abstract:
The invention provides compounds of Formulas Ia-Ib, stereoisomers or pharmaceutically acceptable salts thereof, wherein A, X, Ra, R1, R2, R4, R5 and R16 are defined herein, a pharmaceutical composition that includes a compound of Formulas Ia-Ib and a pharmaceutically acceptable carrier, adjuvant or vehicle, and methods of using the compound or composition in therapy.