T cell immunoglobulin and mucin domain 1 (TIM-1) is a type I transmembrane protein that was originally described as kidney injury molecule 1 (KIM-1) due to its elevated expression in kidney and urine after renal injury. TIM-1 expression is also upregulated in several human cancers, most notably in renal and ovarian carcinomas, but has very restricted expression in healthy tissues thus representing a promising target for antibody-mediated therapy. To this end we have developed a fully human monoclonal IgG1 antibody specific for the extracellular domain of TIM-1. This antibody was shown to bind purified recombinant chimeric TIM-1-Fc protein and TIM-1 expressed on a variety of transformed cell lines, including Caki-1 (human renal clear cell carcinoma), IGROV-1 (human ovarian adenocarcinoma) and A549 (human lung carcinoma). Internalization studies using confocal microscopy revealed the antibody was rapidly internalized by cells in vitro, and internalization was confirmed by quantitative imaging flow cytometry. An antibody-drug conjugate (ADC) was produced with the anti-TIM-1 antibody covalently linked to the potent cytotoxin, monomethyl auristatin E (MMAE), and designated CDX-014. The ADC was shown to exhibit in vitro cytostatic or cytotoxic activity against a variety of TIM-1 expressing cell lines, but not on TIM-1 negative cell lines. Using the Caki-1, IGROV-1, and A549 xenograft mouse models, CDX-014 showed significant anti-tumor activity in a clinically relevant dose range. Safety evaluation in non-human primates has demonstrated a good profile and led to the initiation of clinical studies of CDX-014 in renal cell carcinoma and potentially other TIM-1 expressing tumors.
- Received June 17, 2016.
- Revision received September 15, 2016.
- Accepted September 18, 2016.
- Copyright ©2016, American Association for Cancer Research.