(HealthDay News) – Continuing use of bevacizumab (Avastin) in combination with second-line chemotherapy improves overall survival (OS) and progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC) who have progressed after discontinuation of first-line bevacizumab and chemotherapy, according to the results of a Phase III study presented at the annual meeting of the American Society of Clinical Oncology, held from June 1–5 in Chicago.

Dirk Arnold, MD, from the University Clinic Eppendorf in Hamburg, Germany, and colleagues randomized 820 patients with unresectable, histologically-confirmed mCRC, who had progressed within three months after discontinuation of first-line bevacizumab plus chemotherapy, to receive second-line fluoropyrimidine-based chemotherapy with bevacizumab (2.5mg/kg/week equivalent; 409 patients) or without bevacizumab (411 patients). The choice of oxaliplatin– or irinotecan-based second-line chemotherapy was dependent on the regimen used in first-line treatment.

The researchers found that the median OS was significantly longer in those receiving bevacizumab and chemotherapy, compared to those receiving only chemotherapy (11.2 vs. 9.8 months; hazard ratio [HR], 0.81), as was median PFS (5.7 vs. 4.1 months; HR, 0.68). The adverse event profile was similar to previously reported data for bevacizumab and chemotherapy. When compared with historical data from bevacizumab treatment in first- and second-line mCRC treatment, bevacizumab-related adverse events were not increased by continuing treatment beyond progression.

“By simply switching chemotherapy drugs when the cancer progresses and continuing with bevacizumab, we can make second-line treatment even more powerful,” Arnold said in a statement. “This finding will likely spur research into other cancer types that are sensitive to both bevacizumab and chemotherapy.”

Several authors disclosed financial ties to pharmaceutical companies, including Genentech/Roche, the manufacturer of bevacizumab.

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