Clinical efficacy and safety of synthetic thymic peptides with chemotherapy for non-small cell lung cancer in China: A systematic review and meta-analysis of 27 randomized controlled trials following the PRISMA guidelines

Background: Synthetic thymic peptides (sTPs) are used with chemotherapy to treat non-small cell lung cancer (NSCLC). In this study, we have performed a systematic review and meta-analysis of published trials to confirm the clinical efficacy and safety of sTPs, and determine the optimal types, usages, and sTP/chemotherapy combinations to produce the desired responses. Materials and methods: We collected all studies regarding combined sTP therapy and chemotherapy for NSCLC from the Chinese and English databases (up to October 2018). Bias risk was evaluated for each. Data for metaanalysis was extracted using a pre-designed form. Evidence quality was rated using the Grading of Recommendations Assessment, Development and Evaluation approach. Results: We included 27 randomized controlled trials containing 1925 patients, most with unclear bias risk. Combining sTPs with chemotherapy significantly increased the objective response rate [1.28, (1.13 to 1.45)], disease control rate [1.10, (1.01 to 1.18)], quality of life (QOL) [2.05, (1.62, 2.60)], and 1-year overall survival rate [1.43, (1.15 to 1.78)], with decreased risks of neutropenia, thrombocytopenia, and gastrointestinal reactions. Optimal conditions included treatment in combination with gemcitabine or navelbine and cisplatin, twice a week, with one 3-week cycle. In these conditions, thymosin al improved both antitumor immunity and tumor response. Most results had good robustness, and their quality ranged from moderate to very low. Conclusions: The results suggest that treatment with sTPs, especially thymosin al, and concomitant chemotherapy is beneficial to the patient, and provide evidence for optimal treatment regimens that may increase patient QOL and survival.