DM1-SMe is a potent maytansinoid microtubular inhibitor and an unconjugated DM1 as a mixed disulfide with thiomethane to cap its sulfhydryl group. DM1-SMe can be readily conjugate to the SH group of an antibody to form antibody-drug conjugate (ADC). .
DM1-SMe; DM1-SSMe; maytansinoid derivative with ADC linker. Maytansine or mertansine or emtansine derivative; N2'-deacetyl-N2'-[3-(methyldithio)-1-oxopropyl]maytansine.
Soluble in DMSO, not in water
Structure-activity-relationship studies had identified the C3 ester side chain as a critical element for antitumor activity of maytansinoids. The maytansinoids bearing the methyl group at C3 position with D configuration were about 100 to 400-fold less cytotoxic than their corresponding L-epimers toward various cell lines. IMGN901 and DM1-SMe (unconjugated DM1 as a mixed disulfide with thiomethane to cap its sulfhydryl group) were tested in vitro at concentrations ranging from 0.01 nM to 0.1 µM and 0.3 pM to 3 nM, respectively. IMGN901 was tested against a subset of PPTP solid tumor xenografts focusing on those with high CD56 expression.The combination of IMGN901 with topotecan was also evaluated.
Neuroblastoma models expressed CD56 at or above the median expression level for all PPTP xenografts and cell lines. Neuroblastoma cell lines demonstrated relatively low sensitivity to DM1-SMe compared to other cell lines, but the sensitivity of neuroblastoma cell lines to IMGN901 was comparable to that of non-neuroblastoma cell lines. In vivo, objective responses were observed in 9 of 24 (38%) models including, three of seven neuroblastoma xenografts, and two of seven rhabdomyosarcoma xenografts. All xenografts with objective responses showed homogeneous high-level staining by IHC for CD56, but not all xenografts with homogenous high-level staining had objective responses. Combined with topotecan, IMGN901 demonstrated therapeutic enhancement against two of four neuroblastoma models.
2 years if stored properly
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).