Clinical Study on the Efficacy of Bevacizumab in Combination with Pembrolizumab on Cellular Immune Function in the Treatment of Driver Gene-Negative Stage IV Lung Adenocarcinoma

PURPOSE: To explore the efficacy of bevacizumab in combination with PD-1 immune drug pembrolizumab on cellular immune function in the treatment of driver gene-negative stage IV lung adenocarcinoma and its short-term survival effect. METHODS: From February 2020 to December 2021, 85 patients with driver gene-negative stage IV lung adenocarcinoma were admitted to our hospital and treated with first-line therapy, and their clinical records were reviewed retrospectively. According to the treatments, the patients were separated into two groups the combination group (n = 45) and the control group (n = 40). The treatment regimen of the control group was an AP chemotherapy regimen (pemetrexed combined with cisplatin) + PD-1 immune drug pembrolizumab. The treatment regimen of the combination group was AP chemotherapy regimen + PD-1 immune drug pembrolizumab combined with bevacizumab. We evaluated the pre- and post-treatment cellular immunological function of the two patient groups and discussed the difference between them. RESULTS: There was a substantial difference in the overall effective rate and the disease control rate between the two groups, with the former being 27.50% compared to 48.89% and the latter being 72.50% compared to 93.33% among these 85 patients studied. The KPS for the combination group improved and stayed at 91.11% after treatment, which is considerably better than the KPS for the control group, which was 42.50% (χ(2) = 23.09, P < 0.05). There was no significant difference (P > 0.05) in the numbers of CD3+, CD4+, CD19+, CD8+, or CD4+/CD8+ cells pretreatment between the two groups, but after treatment, the combination group had significantly higher numbers of all these cells. Neither the CD8+ nor the CD19+ level was significantly different between the control and combination groups (P > 0.05). Furthermore, the incidence of common clinical side effects was similar between the two groups (P > 0.05). Proteinuria, tiredness, increased alanine aminotransferase, hypertension, immunological pneumonia, muscle pain, arthralgia, hypothyroidism, etc. were the most common side effects reported among both groups throughout therapy. A grade IV side effect is rare. After follow-up until March 2022, the median PFS for the control group was 9.00 ± 1.65 months (95% CI, 5.76–12.24) and the mean PFS was 11.48 ± 0.91 months (95% CI, 9.69–13.26). Comparison of the median PFS of the combination group (13.00 ± 1.10) months (95% CI: 10.84–15.16) with the average PFS of the group (15.52 ± 0.88) months (95% CI = 13.79–17.25) reveals a statistically significant difference (P < 0.05). CONCLUSION: Combining bevacizumab with the PD-1 immune medication pembrolizumab to treat patients with stage IV lung adenocarcinoma improves the quality of life, short-term therapeutic effectiveness, immune function, and PFS.