Reinforcement of antitumor effect of micelles containing anticancer drugs by binding of an anti-tissue factor antibody without direct cytocidal effects.

It has been preclinically and clinically proven that anticancer agent-incorporating (ACA-incorporating) polymeric micelles selectively accumulate in tumor via the enhanced permeability and retention (EPR) effect, yielding a wider therapeutic window and greater safety than conventional low-molecular weight ACAs. To increase the antitumor effect of these safer micelle formulations, epirubicin-incorporating polymer micelles (NC-6300) conjugated with monoclonal antibodies (mAbs) have been prepared. In this study, we used two types of mAb: an anti-tissue factor (TF) mAb that does not exert a direct cytocidal effect, and an anti-HER2 mAb that has a direct cytocidal effect. We compared the antitumor effects and pharmacological properties of the two types of antibody conjugated to NC-6300. Immunomicelles conjugated to anti-TF mAb exerted greater antitumor activity toward TF-positive stomach cancer than the combination of anti-TF mAb and NC-6300, and were distributed more uniformly throughout TF-positive tumor tissue than NC-6300. On the other hand, immunomicelles conjugated to anti-HER2 mAb did not exert significant antitumor activity toward HER2-positive stomach cancer relative to the combined use of anti-HER2 mAb and NC-6300. Thus, this immunomicelle-based strategy may be useful for antibodies that target cancer as pilot molecules even when the antibodies themselves do not have an antitumor effect.

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Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.

Déclaration de conflit d'intérêts

Declaration of Competing Interest Yasuhiro Matsumura is one of co-founders and stock holders of RIN Institute Inc. Masahiro Yasunaga is a stock holder of RIN Institute Inc. The other authors declare no conflict of interest.