MI130004, a Novel Antibody–Drug Conjugate Combining Trastuzumab with a Molecule of Marine Origin, Shows Outstanding In Vivo Activity against HER2-Expressing Tumors

Abstract

In the search for novel payloads to design new antibody-drug conjugates (ADC), marine compounds represent an interesting opportunity given their unique chemical features. PM050489 is a marine compound that binds β-tubulin at a new site and disrupts the microtubule network, hence leading to mitotic aberrations and cell death. PM050489 has been conjugated to trastuzumab via Cys residues through a noncleavable linker, and the resulting ADC, named MI130004, has been studied. Analysis of MI130004 delivered data consistent with the presence of two molecules of PM050489 per antibody molecule, likely bound to both sides of the intermolecular disulfide bond connecting the antibody light and heavy chains. The antitumor activity of MI130004 was analyzed and in different cell lines of diverse tumor origin (breast, ovary, and gastric cancer) expressing different levels of HER2. MI130004 showed very high potency and good selectivity for tumor cells that overexpressed HER2. At the cellular level, MI130004 impaired tubulin polymerization, causing disorganization and disintegration of the microtubule network, which ultimately led to mitotic failure, mirroring the effect of its payload. Treatment with MI130004 in mice carrying histologically diverse tumors expressing HER2 induced a long-lasting antitumor effect with statistically significant inhibition of tumor growth coupled with increases in median survival time compared with vehicle or trastuzumab. These results strongly suggest that MI130004 is endowed with remarkable anticancer activity and confirm the extraordinary potential of marine compounds for the design of new ADCs..

CD13 as a new tumor target for antibody-drug conjugates: validation with the conjugate MI130110

“…Reagents PM050489, PM120160 (the result of adding a noncleavable linker to PM050489 as depicted in Fig. 1a, synthetic process described in [27]), and MI130110 were prepared in PharmaMar S.A. Chromatography reagents and materials were from GE Healthcare (Buckinghamshire, UK). Unless otherwise stated, reagents were purchased from Sigma-Aldrich (St Louis, MO).…”

“…A colorimetric assay based on the reduction of 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used for quantitative measurement of cell viability as already described [27].…”

“…However, it is not known whether the complex formed by CD13 and a suitable ADC would be efficiently internalized and processed intracellularly. We have recently published the successful use of PM050489, a marine molecule capable of binding tubulin at a novel site with nM affinity [25,26], to prepare an ADC using a noncleavable linker and the resulting conjugate MI130004 exhibited outstanding activity in several murine xenograft models for human tumors [27]. Prompted by this successful experience and urged by the curiosity to explore the potential of CD13 as a novel ADC target, we have conjugated PM050489 to a monoclonal anti-CD13 antibody and have investigated the biological effects of this ADC, called MI130110, in vitro as well as in in vivo models.…”

Clearance of solvents and small molecule impurities in antibody drug conjugates via ultrafiltration and diafiltration operation

“…[9][10][11] In this article we focus on two commonly utilized cosolvents and three small molecules (see Table 1) that are frequently present in the UF/DF unit operation. [9][10][11] In this article we focus on two commonly utilized cosolvents and three small molecules (see Table 1) that are frequently present in the UF/DF unit operation.…”

“…For ADCs using reduced interchain cysteines for conjugation, the chemical steps include reduction of interchain disulfide bonds, conjugation, and quench of thiol-reactive drug-linkers before the final UF/DF operation. [9][10][11] In this article we focus on two commonly utilized cosolvents and three small molecules (see Table 1) that are frequently present in the UF/DF unit operation. The clearance of druglinker related species by UF/DF is specific to each ADC program and needs to be studied separately to meet the specification for each program, therefore is beyond the scope of this article.…”