(ChemotherapyAdvisor) – Patients with locally advanced or metastatic pancreatic neuroendocrine tumors (NETs) appear to benefit from the combination of temozolomide and bevacizumab, a phase 2 study has shown. The results, published in the Journal of Clinical Oncology online July 9, found response rates to be 33% among those with NETs compared with no response among patients with carcinoid tumors, consistent with prior studies.
Jennifer A. Chan, MD, MPH, of Dana-Farber Cancer Institute, Boston, MA, and colleagues treated 34 patients—56% with carcinoid and 44% with pancreatic NETs—with oral temozolomide 150mg/m2/day days 1–7 and days 15–21 with bevacizumab 5mg/kg/day IV days 1 and 15 of each 28-day cycle. Prophylaxis against Pneumocystis carinii and varicella zoster was administered.
Five of 34 patients had an overall radiographic response rate of 15%. Response rates differed between those with pancreatic NETs, 33% (5 of 15), vs carcinoid tumors, 0% (0 of 19). Median progression-free survival (PFS) was 11.0 months, 14.3 months for pancreatic NETs vs 7.3 months for carcinoid tumors. Median overall survival (OS) was 33.3 months, 41.7 months for pancreatic NETs vs 18.8 months for carcinoid tumors. “The shorter-than-expected PFS and OS durations in patients with carcinoid tumors may reflect a more heavily pretreated patient population,” the investigators wrote.
Grade 3 to 4 toxicities included lymphopenia (53%) and thrombocytopenia (18%).
“Further studies examining the optimal dose regimen for temozolomide and the relative contributions of temozolomide and bevacizumab to the antitumor activity and PFS are warranted,” they concluded.