Bispecific antibodies (anti-mPEG/anti-HER2) for active tumor targeting of docetaxel (DTX)-loaded mPEGylated nanocarriers to enhance the chemotherapeutic efficacy of HER2-overexpressing tumors.

Anti-mPEG/anti-human epidermal growth factor receptor 2 (HER2) bispecific antibodies (BsAbs) non-covalently bound to a docetaxel (DTX)-loaded mPEGylated lecithin-stabilized micellar drug delivery system (LMDDs) were endowed with active targetability to improve the chemotherapeutic efficacy of DTX. DTX-loaded mPEGylated LMDDs formulations were prepared using lecithin/DSPE-PEG(2K or 5K) nanosuspensions to hydrate the thin film, and then they were subjected to ultrasonication. Two BsAbs (anti-mPEG/anti-DNS or anti-HER2) were simply mixed with the LMDDs to form BsAbs-LMDDs formulations, respectively, referred as the DNS-LMDDs and HER2-LMDDs. Results demonstrated that the physical characteristics of the BsAbs-LMDDs were similar to those of the plain LMDDs but more slowly released DTX than that from the LMDDs. Results also showed that the HER2-LMDDs suppressed the growth of HER2-expressing MCF-7/HER2 tumors, increasing the amount taken up via an endocytosis pathway leading to high drug accumulation and longer retention in the tumor. In conclusion, the BsAbs-LMDDs preserved the physical properties of the LMDDs and actively targeted tumors with a drug cargo to enhance drug accumulation in tumors leading to greater antitumor activity against antigen-positive tumors.