Initial testing (Stage 1) of the antibody-maytansinoid conjugate, IMGN901 (Lorvotuzumab mertansine), by the pediatric preclinical testing program.

Journal Article

BACKGROUND: IMGN901 (lorvotuzumab mertansine) is an antibody-drug conjugate composed of a humanized antibody that specifically binds to CD56 (NCAM, neural cell adhesion molecule) and that is conjugated to the maytansinoid, DM1 (a microtubule targeting agent). PROCEDURES: 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. RESULTS: 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. CONCLUSIONS: IMGN901 has anti-tumor activity against some CD56 expressing pediatric cancer models. High expression of CD56 is a biomarker for in vivo response, but resistance mechanisms to IMGN901 in some high CD56 expressing lines need to be defined.

Full Text

Duke Authors

Cited Authors

  • Wood, AC; Maris, JM; Gorlick, R; Kolb, EA; Keir, ST; Reynolds, CP; Kang, MH; Wu, J; Kurmasheva, RT; Whiteman, K; Houghton, PJ; Smith, MA

Published Date

  • November 2013

Published In

Volume / Issue

  • 60 / 11

Start / End Page

  • 1860 - 1867

PubMed ID

  • 23798344

Electronic International Standard Serial Number (EISSN)

  • 1545-5017

Digital Object Identifier (DOI)

  • 10.1002/pbc.24647

Language

  • eng

Conference Location

  • United States