Effects of the COVID-19 pandemic on publication landscape in chimeric antigen receptor-modified immune cell research

Chimeric antigen receptors (CARs) are artificial receptors introduced mainly into T cells. CAR-induced immune cell (CARi) products have achieved impressive success rates in treating some difficult-to-treat hematological malignancies. Here, we describe effects of the global COVID-19 pandemic on CARi publication landscape. Due to the pandemic, the total number of publications decreased in 2020 compared to 2019 in all fields of cancer immunotherapy except CARi. Nearly exponential increases in the number of CARi publications slowed-down in 2020 for the first time in the past 11 years. There were more CARi than coronavirus publications until 2020 when coronavirus publications increased over 5,000% compared to 2019 (575 publications in 2019 vs. 30,390 in 2020). Unlike cancer immunotherapy where the majority of the publications consist of conference abstracts and review articles, majority of the coronavirus publications are original research articles. There are more coronavirus publications in Pubmed than Embase. The opposite is true for CARi publications. Our analysis of the data from the FDA Adverse Event Reporting System (FAERS) show significantly higher death rate in patients treated with Kymirah than Yescarta (28.14% vs. 16.02%). Kymirah and Yescarta are the two main CAR T cell products for treatment of DLBCL and/or B-ALL. However, despite being highly significant, this result is not easily interpretable due to multiple confounding variables in the FAERS data. Our analysis additionally suggest that the significant effects of co-stimulatory domains (4-1BB vs. CD28) consistently reported in preclinical studies do not translate into clinical results. Our manual curation of the CARi publications in PubMed shows that only 5.2% of the publications report results from CARi clinical trials, although we found 663 clinical trials listed on ClinicalTrials.gov database. In conclusion, publication landscape in CARi as well as other fields of cancer immunotherapy has changed due to the global COVID-19 pandemic. This trend will likely continue in the near future. CARi research is now in need of increased measures by publishers to reduce repetitive and/or duplicate publications and more stringent criteria for data entry into public databases including PubMed, Embase, ClinicalTrials.gov, and FAERS to advance this important field of medical research.