OSS-128167 is a selective SIRT6 inhibitor with IC₅₀s of 89, 1578 and 751 μM for SIRT6, SIRT1 and SIRT2, respectively. OSS_128167 inhibits SIRT6 in the micromolar range, but shows promising selectivity, since its IC₅₀ value for SIRT6 is approximately 17 times lower compare to the IC₅₀for SIRT1 and 9 times lower compare to SIRT2. OSS_128167 (200 μM) induces chemosensitization in primary multiple myeloma (MM) cells (NCI-H929), as well as in melphalan-resistant (LR-5) and doxorubicin-resistant (Dox40) MM cell lines.