Determination of the Timing of Bevacizumab Administration in Osimertinib and Bevacizumab Combination Therapy

Abstract Background: In recent years, studies have suggested that EGFR-TKIs can act synergistically with vascular endothelial growth factor inhibitors. In osimertinib and bevacizumab combinatorial treatment, the timing for the addition of bevacizumab is yet to be clearly defined. Methods: From April 1, 2018, to January 1, 2021, a total of 31 patients were enrolled in this study. Osimertinib was orally administered once every day at a dose of 80 mg. There was a treatment cycle every 21 days. Bevacizumab (7.5 mg/kg) was administered by drip infusion on the first day of each cycle. Results: 31 patients included in this study.The median progression-free survival were 13.47 months (range: 7.72–19.21 months), respectively. A total of 26 patients were subjected to response analysis. Of the 26 patients, 6 (23.08%) had a partial response, 20 (72.92%) had stable disease, and none had progressive disease. The overall response rate was 23.07%. Sixteen patients had central nervous system (CNS) disease. The CNS response rate in patients with measurable and non-measurable diseases was 71%. All patients were evaluated for the toxic effects of the drugs. The average use of bevacizumab was 9.13 months (range: 3.5–13.03 months). The treatment modality of “T to A+T” was found to yield better benefits to the patients than the treatment modality of “A+T” (HR=0.165, 95% CI: 0.029–0.928, P=0.041). EGFR21 had a significantly higher risk of progression than EGFR19 (HR=6.998, 95% CI: 2.101–23.311, P=0.002). Conclusion: The treatment modality of “T to A+T” was found to be better than that of “A+T” and can prolong the time of drug resistance. Patients with EGFR19 had a better prognosis than those with EGFR21, regardless of the treatment modality.