Randomized Phase II Study of Ramucirumab or Icrucumab in Combination with Capecitabine in Patients with Previously Treated Locally Advanced or Metastatic Breast Cancer

Background Icrucumab (ICR) and ramucirumab (RAM) bind vascular endothelial growth factor (VEGF) receptors 1 and 2 (VEGFR‐1 and ‐2), respectively. This open‐label, randomized phase II study evaluated their efficacy and safety in combination with capecitabine (CAP) in patients with previously treated unresectable, locally advanced or metastatic breast cancer. Methods Patients were randomly assigned (1:1:1) to receive CAP (1,000 mg/m2 orally twice daily, days 1–14) alone or in combination with RAM (10 mg/kg intravenously [IV], days 1 and 8) (RAM + CAP) or ICR (12 mg/kg IV, days 1 and 8) (ICR + CAP) every 21 days. The primary endpoint was progression‐free survival (PFS). Secondary endpoints included overall survival (OS), tumor response, safety, and pharmacokinetics. Results Of 153 patients randomized, 150 received treatment. Median PFS (95% confidence interval) was 22.1 (12.1–36.1) weeks on RAM + CAP, 7.3 (6.3–13.0) weeks on ICR + CAP, and 19.0 (12.1–24.3) weeks on CAP (hazard ratios [HRs]: 0.691, p = .1315, RAM + CAP versus CAP; 1.480, p = .0851, ICR + CAP versus CAP). Median OS was 67.4 weeks on RAM + CAP, 62.1 weeks on ICR + CAP, and 71.6 weeks on CAP (HRs: 1.833, p = .0283, RAM + CAP versus CAP; 1.468, p = .1550, ICR + CAP versus CAP). There was no statistically significant difference in PFS or OS between either combination arm and CAP. Treatment‐related adverse events more frequent (by ≥10%) on RAM + CAP than on CAP were constipation, decreased appetite, headache, epistaxis, and hypertension. Those more frequent (by ≥10%) on ICR + CAP than CAP were anemia, increased lacrimation, periorbital edema, nausea, vomiting, peripheral edema, facial edema, dehydration, and dyspnea. Conclusion Combining RAM or ICR with CAP did not improve PFS in the targeted study population. Implications for Practice Icrucumab and ramucirumab are recombinant human IgG1 monoclonal antibodies that bind vascular endothelial growth factor (VEGF) receptors 1 and 2 (VEGFR‐1 and ‐2), respectively. VEGFR‐1 activation on endothelial and tumor cell surfaces increases tumor vascularization and growth and supports tumor growth via multiple mechanisms, including contributions to angiogenesis and direct promotion of cancer cell proliferation. Strong preclinical and clinical evidence suggests key roles for VEGF and angiogenesis in breast cancer growth, invasion, and metastasis. This randomized phase II study evaluated the efficacy and safety of each antibody in combination with capecitabine in p