A randomized trial of bevacizumab, an anti-vascular endothelial growth factor antibody, for metastatic renal cancer

Abstract

Background: Mutations in the tumor-suppressor gene VHL cause oversecretion of vascular endothelial growth factor by clear-cell renal carcinomas. We conducted a clinical trial to evaluate bevacizumab, a neutralizing antibody against vascular endothelial growth factor, in patients with metastatic renal-cell carcinoma.

Methods: A randomized, double-blind, phase 2 trial was conducted comparing placebo with bevacizumab at doses of 3 and 10 mg per kilogram of body weight, given every two weeks; the time to progression of disease and the response rate were primary end points. Crossover from placebo to antibody treatment was allowed, and survival was a secondary end point.

Results: Minimal toxic effects were seen, with hypertension and asymptomatic proteinuria predominating. The trial was stopped after the interim analysis met the criteria for early stopping. With 116 patients randomly assigned to treatment groups (40 to placebo, 37 to low-dose antibody, and 39 to high-dose antibody), there was a significant prolongation of the time to progression of disease in the high-dose--antibody group as compared with the placebo group (hazard ratio, 2.55; P<0.001). There was a small difference, of borderline significance, between the time to progression of disease in the low-dose--antibody group and that in the placebo group (hazard ratio, 1.26; P=0.053). The probability of being progression-free for patients given high-dose antibody, low-dose--antibody, and placebo was 64 percent, 39 percent, and 20 percent, respectively, at four months and 30 percent, 14 percent, and 5 percent at eight months. At the last analysis, there were no significant differences in overall survival between groups (P>0.20 for all comparisons).

Conclusions: Bevacizumab can significantly prolong the time to progression of disease in patients with metastatic renal-cell cancer.

Figure 1. Kaplan–Meier Analysis of Survival Free of Tumor Progression for Patients Receiving High-Dose Bevacizumab (Panel A) or Low-Dose Bevacizumab (Panel B), as Compared with Placebo

The high dose of bevacizumab was 10 mg per kilogram of body weight. The low dose of bevacizumab was 3 mg per kilogram. Doses were given every two weeks. P values were calculated by the log-rank test.

Figure 2. Serial Radiographs of a Patient Treated with High-Dose Bevacizumab

Panel A shows the pretreatment assessment (arrows indicate lymph-node metastases). Panel B shows a radiograph obtained two years later, when treatment was stopped during a partial response. Panel C shows relapse of tumor six months thereafter. Panel D shows a second partial response 3 months after therapy was restarted, which is ongoing at more than 18 months as of this writing.

Figure 3. Overall Survival of Patients Receiving Placebo, Low-Dose Bevaci-zumab, or High-Dose Bevacizumab

There were no significant differences among the treatment groups.