The impact of immune checkpoint inhibitors in patients with chronic lymphocytic leukemia (CLL) A protocol for a systematic review and meta-analysis of randomized controlled trials

Introduction: The global burden of chronic lymphocytic leukemia (CLL) has constantly increased over the years, with a current incidence of 3.5 cases per 100,000 people. Although the conventional drugs used to treat CLL patients have been effective treatment failure rate in some of the patients is alarming. Therefore, as a result, novel treatment strategies with improved outcomes such as the blockade of immune checkpoints have emerged. However, consensus on the risk-benefit effects of the using these drugs in patients with CLL is controversial and has not been comprehensively evaluated. This systemic review and meta-analysis provide a comprehensive synthesis of available data assessing adverse events associated with the use of immune checkpoint inhibitors in patients with CLL as well as their influence on the overall survival rate. Methods: This protocol for a systematic review and meta-analysis has been prepared in accordance with Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 guidelines. A search strategy will be developed using medical subject headings words in PubMed search engine with MEDLINE database. The search terms will also be adapted for gray literature, Embase, and Cochrane Central Register of Controlled Trials electronic databases. Two reviewers (AN and SRN) will independently screen studies, with a third reviewer consulted in cases of disagreements using a defined inclusion and exclusion criteria. Data items will be extracted using a predefined data extraction sheet. Moreover, the risk of bias and quality of the included studies will be appraised using the Downs and Black checklist and the quality and strengths of evidence across selected studies will be assessed using the Grading of Recommendations Assessment Development and Evaluation approach. The Cochran's Q statistic and the I(2)statistics will be used to analyze statistical heterogeneity across studies. If the included studies show substantial level of statistical heterogeneity (I-2 > 50%), a random-effects meta-analysis will be performed using R statistical software. Ethics and dissemination: The review and meta-analysis will not require ethical approval and the findings will be published in peer-reviewed journals and presented at local and international conferences. This review may help provide clarity on the risk-benefit effects of using immune checkpoint inhibitors in patients with CLL. Systematic review registration: International prospective Register of Systematic Reviews (PROSERO) number: CRD42020156926.