Forestplots of comparisons between experimental treatments and standard treatments in terms of PFS and OS. Bortezomib (BORT) with or without dexamethasone represents the standard treatment (ST) in (A) PFS and (C) OS; IMiDs represent the standard treatment in (B) PFS and (D) OS. Subgroups have been created according to drug classes. CARF, carfilzomib; ET, experimental treatment; W, weight.