Cardiotoxic effects of the novel approved anti-ErbB2 agents and reverse cardioprotective effects of ranolazine

PURPOSE: Pertuzumab, a novel anti-epidermal growth factor receptor 2 humanized monoclonal antibody, and trastuzumab-emtansine (TDM1), a novel antibody–drug conjugate made up of trastuzumab covalently linked to the highly potent microtubule inhibitory agent DM1, have been recently approved by the US Food and Drug Administration for increasing the efficiency and safety of breast cancer therapy with trastuzumab. We investigated for the first time the potential cardiotoxic effects of pertuzumab and TDM1, which are not yet fully elucidated, and we tested whether ranolazine could blunt their cardiotoxicity. METHODS: The cardiotoxic effects were tested in vitro on rat cardiomyoblasts, human fetal cardiomyocytes, adult-like cardiomyocytes, and in vivo on a mouse model. RESULTS: All the treated cardiac cell lines were significantly affected by treatment with the tested drugs. Surprisingly, TDM1 showed stronger inhibitory effects on cardiac cells with respect to trastuzumab and pertuzumab by more significantly reducing the cell viability and by changing the morphology of these cells. TDM1 also affected the beating phenotype of adult-like cardiomyocytes in vitro and reduced fractional shortening and ejection fraction in vivo in a mouse model. We also found that ranolazine attenuated not only the cardiotoxic side effects of trastuzumab but also those of pertuzumab and TDM1, when used in combinatorial treatments both in vitro and in vivo, as demonstrated by the recovery of fractional shortening and ejection fraction values in mice pretreated with TDM1. CONCLUSION: We demonstrated that it is possible to predict the eventual cardiotoxic effects of novel approved anticancer drugs early by using in vitro and in vivo approaches, which can also be useful to screen in advance the cardioprotective agents, so as to avoid the onset of unwanted cardiotoxic side effects.