New Research: Avastin doesn’t extend survival in older lung cancer patients
New research shows no significant benefit for seniors (65+) with non-small cell lung cancer taking Avastin (bevacizumab) with the chemotherapies carboplatin and paclitaxel.
Avastin is a targeted therapy that prevents new blood vessels from forming. For tumors to grow, they need nutrients and oxygen from the blood; without an increased blood supply from new blood vessels, the tumor will starve. Avastin attacks a specific protein (VEGF) produced by tumors to hijack new blood vessels.
Avastin was approved for treatment of advanced non-small cell lung cancer in combination with chemotherapy in 2006, based on the results from a large, randomized trial (878 patients) conducted by the Eastern Cooperative Oncology Group (ECOG), funded by the National Cancer Institute. The original study found that patients who took Avastin and chemotherapy had a significant increase in overall survival (12.3 months vs 10.3 months). However, more recent analyses looked at responses to Avastin/chemotherapy combination in older patients (aged 65+ or 70+) and found no significant benefit, prompting further investigation.
This most recent study analyzed Medicare patients included in the National Cancer Institute's SEER (Surveillance, Epidemiology and End Results) program, enabling the researchers to evaluate 4168 lung cancer patients, diagnosed between 2002-2007, aged 65 or older, with stage IIIB or IV non-small cell lung cancer, and first line chemotherapy with or without Avastin. Among these patients, researchers did not find increased survival from treatment with Avastin/chemotherapy compared to chemotherapy alone. Honing in on this age group, researchers found a median survival of only 9.7 months.
Because the study was linked to Medicare, the researchers were also able to evaluate how the medical oncology community was prescribing Avastin. Of patients diagnosed in 2006 and 2007, only 20% and 22% were prescribed Avastin in combination with chemotherapy as first line treatment. For critics who assume doctors are eager to prescribe the newest, most expensive treatments, this shows that doctors rely on definitive evidence before widely adopting a new treatment.
But for this analysis, that means only 7.6% (318 of 4,168) of patients received Avastin. A larger number of patients may yield different results. Additionally, while the study group was much larger than the ECOG trial, it was limited to Medicare patients living in a SEER region, and may not be representative of all patients (though likely more so than the selected trial participants). Also, they weren't able to look at biomarkers or other selection criteria that could define certain groups of patients with better or worse outcomes.
Doctors should continue to be judicious in prescribing Avastin in older patients. There may be other factors - not considered for this study - that may make Avastin a positive or negative option as therapy for a particular patient. Researchers are continuing to hunt for biomarkers that can tell us if a targeted therapy, like Avastin, is likely to be beneficial to certain patients, and investigating new drugs that can stop blood-vessel formation in tumors. For example, UALC is funding Dr. Lidija Covic (Tufts University) to study a new way to block this process. The more drugs and treatments in our arsenal, the more likely doctors will be able to choose the best treatment for each patient.
Ramalingam SS, et al., Outcomes for elderly, advanced-stage non small-cell lung cancer patients treated with bevacizumab in combination with carboplatin and paclitaxel: analysis of Eastern Cooperative Oncology Group Trial 4599. J Clin Oncol. 2008 Jan 1;26(1):60-5.
Sandler A, et al., Paclitaxel-carboplatin alone or with bevacizumab for non-small cell lung cancer. N Eng J Med. 2006; 355(24): 2542-2550.
Zhu J, et al., Carboplatin and Paclitaxel with vs without bevacizumab in older patients wiht advanced non-small cell lung cancer. JAMA 2012 Apr 18; 307(15): 1593-1601.