The research status of immune checkpoint blockade by anti-CTLA4 and anti-PD1/PD-l1 antibodies in tumor immunotherapy in China A bibliometrics study

Purpose: Using bibliometrics, we analyzed the research status of immune checkpoint blockade (ICB, a popular tumor immunotherapy method represented by antibodies targeted CTLA-4 and PD-1/PD-L1) in tumor immunotherapy in China during the past 2 decades. Methods: Articles in Science Citation Index Expanded (SCI-EXPANDED), patents in Thomson Innovation, and drugs in Cortellis Competitive Intelligence in the field of ICB for tumor immunotherapy from 1996 to 2015 were the subjects of bibliometric analysis. Using database-attached software and Excel, quantitative analyses were performed including examination of the number of documents, citation frequency, h-index, key projects, quantity of publications, public patents, and status of new drug research. Results: The number of publications from 1996 to 2015 in the field of ICB for tumor immunotherapy that came out of China was 380, which was 14.3% of the total publications worldwide and was second only to that of the USA. In the past decade, China has rapidly increased the number of publications and patents in this field. However, indicators of publication influence, such as citation frequency and h-index, were far behind other advanced countries. In addition, the total number of patents in China was much lower than that of the USA. China has introduced 5 drugs for ICB that are being developed for the healthcare market. Conclusion: Tumor immunotherapy research such as ICB in China has developed rapidly with increasing influence in the last 2 decades. However, there is still a relatively large gap compared with the USA. It is expected that China will have greater influence on tumor immunotherapy research in the near future.