USP14 and Miyoshi myopathy: 44, 54 As described in a prior report, robust activity of USP14/UCHL5 inhibition with b-AP15 was observed in delaying the outgrowth of tumor cells in MM-xenotransplanted mice.33 Whereas Tian et al.33 administered b-AP15 at 4 mg/kg on a consecutive day schedule for 14 days, owing to the improved chemistry of VLX1570, we opted for a similar dose but on an alternate day schedule consisting of 12 treatments.