EGFR-TKI Combined With Thymosin Compared With EGFR-TKI Monotherapy In EGFR Mutation Positive Patients With Advanced NSCLC:a Retrospective Study

Background: Epidermal growth factor receptor tyrosine kinase inhibitor(EGFR-TKI)is a standard treatment for non-small cell lung cancer(NSCLC)patients harboring active EGFR mutations.The efficacy and safety of EGFR-TKI combined with immunomodulator thymosin has not been explored.Methods: Eligible patients were histologically or cytologically confirmed as unresectable stage IIIB/IV advanced NSCLC who received EGFR-TKI from January 2008 to November 2017,46 patients who received EGFR-TKI combined with thymosin(Group A)and 238 patients took EGFR-TKI monotherapy were collected.According to three types of EGFR-TKI,patients of these two groups were divided into six subgroups.Six indicators of EGFR mutation status,smoking status,ECOG PS,line of EGFR-TKI treatment,,age and gender,were considered as major matching index.Under the premise of same EGFR-TKI,patients of two subgroups were matched by propensity score matching at a ratio of 1:1,until there were no successful matched patients in these two subgroups.The primary endpoint was progression-free survival(PFS),the secondary endpoints included overall survival(OS),objective response rate(ORR),adverse effects(AEs)and peripheral blood T lymphocyte subsets.Results: By February 20,2019,the median follow-up time was 16 months.The median PFS was 16.2 months in Group A vs.10.2 months in Group B(HR=0.50,95% CI: 0.36-0.69,P = 0.000).The median OS was 32.7 vs.19.7 months(HR=0.48,95%CI: 0.34-0.66,P=0.002)in Group A and Group B.Objective response rate(ORR)in Group A was similar with Group B(59.9% vs.61.1%,P=0.860).Adverse events grade ?2 between two groups shown no difference(P>0.05),however,peripheral blood T lymphocyte subsets of patients after receiving EGFR-TKI monotherapy were decreased.Conclusions: EGFR-TKI plus thymosin significantly improved PFS and OS compared with EGFR-TKI alone in advanced NSCLC with active EGFR mutations.The combination therapy of EGFR-TKI and immunomodulator thymosin offers a new strategy for the treatment of NSCLC with active EGFR mutations.