Cancer Therapy: Preclinical Potential Proinvasive or Metastatic Effects of Preclinical Antiangiogenic TherapyAre Prevented by Concurrent Chemotherapy

Purpose: To resolve a controversy involving the therapeutic impact of antiangiogenic drugs and particularly antibodies targeting the VEGF pathway, namely, a body of preclinical mouse therapy studies showing such drugs can promote invasion and/or distant metastasis when used as monotherapies. In contrast, clinical studies have not shown such promalignancy effects. However, most such clinical studies have involved patients also treated with concurrent chemotherapy highlighting the possibility that chemotherapy may prevent any potential promalignancy effect caused by an antiangiogenic drug treatment. Experimental Design: The impact of antiangiogenic therapy using DC101, an antibody targeting mouse VEGFR-2 with or without concurrent chemotherapy was assessed in multiple human breast cancer xenograft models, where impact on orthotopic primary tumors was evaluated. Metastasis was also assessed during adjuvant and neoadjuvant plus adjuvant therapy, after surgical resection of primary tumors, with the same combination therapies. Results: Antiangiogenic therapy, while blunting tumor volume growth, was found to increase local invasion in multiple primary tumor models, including a patient-derived xenograft, but this effect was blocked by concurrent chemotherapy. Similarly, the combination of paclitaxel with DC101 caused a marked reduction of microor macrometastatic disease in contrast to DC101 monotherapy, which was associated with small increases in metastatic disease. Conclusions: Conventional wisdom is that targeted biologic antiangiogenic agents such as bevacizumab when used with chemotherapy increase the efficacy of the chemotherapy treatment. Our results suggest the reverse may be true as well— chemotherapy may improve the impact of antiangiogenic drug treatment and, as a result, overall efficacy. Clin Cancer Res; 21(24);