What’s next after chemotherapy: bevacizumab alone or bevacizumab plus erlotinib?

This trial compared two treatment strategies following chemotherapy for advanced and metastatic lung cancer patients: bevacizumab (Avastin) alone versus bevacizumab and erlotinib (Tarceva).

Bevacizumab and erlotinib target specific weaknesses found in cancer cells. Bevacizumab works by blocking the tumor’s ability to grow new blood vessels (in order to stop its progression). Erlotinib blocks a specific protein in cancer cells: the epidermal growth factor receptor (EGFR). EGFR is responsible for “telling” cancer cells to grow, especially when a specific genetic mutation is present (EGFR-positive cancers).

Bevacizumab and erlotinib were previously found to improve outcomes when given together with standard chemotherapy. It is hypothesized that continuing treatment with these drugs after chemotherapy (as maintenance treatment) will improve outcomes. It is not clear if the two drugs should be given together in order to prolong the time until further tumor growth occurs (progression free survival) and to improve overall survival.

The present study included 743 patients with advanced or metastatic lung cancer, who were first treated with chemotherapy and bevacizumab. 373 patients continued treatment with bevacizumab alone, while the remaining 370 continued treatment with both bevacizumab and erlotinib. Patients treated with both drugs experienced longer progression free survival than those treated with bevacizumab alone: 4.8 months versus 3.7 months. This benefit was greater in patients who had EGFR-positive cancers. However, the difference in overall survival was not significant: 14.4 months with both drugs versus 13.3 months with bevacizumab alone. There were also more side effects in patients who received both bevacizumab and erlotinib.

Results from this trial showed that continuing treatment with both bevacizumab and erlotinib after chemotherapy improved progression free survival, but not overall survival. Using both drugs also increased the risk for side effects compared to using bevacizumab alone.

Erlotinib is particularly effective in treating EGFR-positive lung cancers. This study only included 52 patients with the EGFR mutation. Further research is needed to determine if maintenance treatment with erlotinib improves survival in this specific patient sub-group.

Consult with your physician regarding the risks and benefits of combined bevacizumab and erlotinib maintenance therapy.