Purpose: Effective systemic therapy for advanced carcinoid is lacking. The combination of bevacizumab (BEV) and pegylated (PEG) interferon alpha-2b was evaluated among patients with metastatic or unresectable carcinoid tumors.
Patients and methods: Forty-four patients on stable doses of octreotide were randomly assigned to 18 weeks of treatment with bevacizumab or PEG interferon alpha-2b. At disease progression (PD) or at the end of 18 weeks (whichever occurred earlier), patients received bevacizumab plus PEG interferon until progression. Functional computer tomography (CT) scans were performed to measure effect on tumor blood flow.
Results: In the bevacizumab arm, four patients (18%) achieved confirmed partial response (PR), 17 patients (77%) had stable disease (SD), and one patient (5%) had PD. In the PEG interferon arm, 15 patients (68%) had SD and six patients (27%) had PD. Progression-free survival (PFS) rates after 18 weeks of monotherapy were 95% in bevacizumab versus 68% on the PEG interferon arm. The overall median PFS for all 44 patients is 63 weeks. Compared with paired baseline measurements on functional CT scans, we observed a 49% (P < .01) and 28% (P < .01) decrease in tumor blood flow at day 2 and week 18 among patients treated with bevacizumab. No significant changes in tumor blood flow were observed following PEG interferon. PEG interferon alpha-2b treatment was associated with decrease in plasma basic fibroblast growth factor (bFGF; P = .04) and increase in plasma interleukin-18 (IL-18; P < .01). No significant changes in bFGF or IL-18 following treatment with bevacizumab were observed.
Conclusion: Bevacizumab therapy resulted in objective responses, reduction of tumor blood flow, and longer PFS in patients with carcinoid than PEG interferon treatment.