A preliminary analysis of integrating thymosin α1 into concurrent chemoradiotherapy and consolidative immunotherapy.

Abstract

e20569 Background: The study aimed to investigate the efficacy of integrating Thymosin into concurrent chemoradiotherapy (CCRT) and consolidative immunotherapy in unresectable locally advanced non-small cell lung cancer (LA-NSCLC). Methods: Ninety-one stage IIIA-IIIC LA-NSCLC patients enrolled from Jan 1, 2020, to Oct 31, 2022 were analyzed retrospectively. All patients received CCRT (total irradiation dose of 60Gy and weekly concurrent docetaxel and cisplatin) and consolidative immunotherapy (Nivolumab/Tislelizumab). Thymosin α1 (1.6 mg) was administered once a week from the start of treatment till 2 months after CCRT or till the last prescription of consolidative immunotherapy. The primary endpoint was progression-free survival (PFS). The secondary endpoints included the overall survival (OS) and toxicity. Results: There were 31 patients who received Thymosin α1 till the last prescription of consolidative immunotherapy, 40 patients received Thymosin α1 till 2 months after CCRT and 20 patients without the administration of Thymosin α1. The median follow-up time was 28.3 months (range 8.2~31.6 months). The median PFS was 26.1 months in Thymosin α1+consolidative immunotherapy group, 15.3 months in Thymosin α1+CCRT group and 12.6 months in control group (P = 0.116). The median OS was not reached in Thymosin α1+consolidative immunotherapy group, 26 months in Thymosin α1+CCRT group and 16.5 months in control group (P = 0.046). The median courses of consolidative immunotherapy were 8 Thymosin α1+consolidative immunotherapy group, 6 in Thymosin α1+CCRT group and 3 in control group (P = 0.060). There were higher ≥grade 3 acute lymphopenia (62.3%) and acute grade 2 pneumonitis (8.0%) in the control group. The long-term use of Thymosin α1 was also found to be related to the lower level of IL-6(P = 0.048), CD 16+NK cells and CD56+NK cells (P = 0.043). Conclusions: The integration of Thymosin α1 into CCRT and consolidative immunotherapy could yield synergistic effect in LA-NSCLC patients. The combination might contribute to prolonged use of consolidative immunotherapy and survival benefit.