Table 2. Strategies to inhibit factor XI.

Agents	Mechanisms of action of FXI inhibitors
Antisense oligonucleotides (ASO)	Reduce hepatic synthesis of FXI by inducing catalytic degradation of FXI mRNA (for example, IONIS-FXI Rx) a
Monoclonal antibodies	Suppress FXIa generation and/or inhibit FXIa activity (for example, BAY1213790 (osocimab) b, MAA868 (abelacimab), AB023)
Small molecules	Bind to catalytic domain (for example, JNJ-70033093, BAY2433334, EP-7041, ONO-5450598)
Aptamers	Bind to FXI and/or FXIa and block its activity

^aFXI ASO for prevention of venous thromboembolism (evaluated in a phase 2 randomized controlled trial: NCT01717761).

^bOsocimab (evaluated in a phase 2 randomized, active-comparator-controlled, multi-center study (NCT03276143) to assess the safety and efficacy of different doses of BAY1213790 for the Prevention of Venous Thromboembolism in Patients Undergoing Elective Primary Total Knee Arthroplasty, Open-label to Treatment and Observer-blinded to BAY1213790 Doses (FOXTROT) ³⁶.