Background: Apixaban 2.5mg twice-daily replaced low-molecular-weight-heparin as thromboprophylaxis (TP) for multiple myeloma (MM) patients receiving outpatient-based chemotherapy considered at high-risk of venous thromboembolism (VTE) on 1st November 2019 in our regional centre (Figure 1).

Aims: This prospective cohort study aimed to assess the safety and efficacy of apixaban as thromboprophylaxis in high-thrombotic risk patients with MM.

Methods: Data was systematically collected from the electronic noting system for service evaluation, retrospectively for the historic cohort (1st Nov 2018 – 1st Nov 2019) prior to introduction of the novel thromboprophylactic strategy, and prospectively (1st Nov 2019– 1st Nov 2020) following the change of local guidelines. Exclusion criteria included antithrombotic treatment other than thromboprophylaxis or contraindication to thromboprophylaxis e.g. thrombocytopenia. Data collected included previous VTE history, thromboprophylactic agent, thrombosis and bleeding events.

Results: There were 102 MM patients in the historic and 147 in the prospective cohort (Table 1). VTE prophylaxis was prescribed in 80% historic and 78% prospective cohort. After the introduction of the amended thromboprophylactic strategy, prescriptions of apixaban increased from 27% to 53%, whilst aspirin prescriptions fell from 62% to 41%.

After the introduction of apixaban, thrombotic events reduced from 3% (3/102) to 1.4% (2/147). All thrombotic events in the historic cohort occurred despite aspirin as thromboprophylaxis and on a pomalidomide-containing regimen. No thrombotic events occurred on prophylactic apixaban in either cohort.

Five bleeding events occurred in the historic cohort: one major bleed (on apixaban TP) and two clinically-relevant non-major bleeding (CRNMB). In the prospective cohort, there was one major bleed (aspirin as TP) and one CRNMB.

Across both cohorts, major bleeding occurred in 1.2% (1/82) and CRNMB in 1.2% (1/82) patients on prophylactic apixaban.

Conclusion(s): This data supports the use of apixaban as thromboprophylaxis in MM patients at high-thrombotic risk, with low thrombotic rates and acceptably low rates of major bleeding and CRNMB.

Figure

Figure 1: Novel thromboprophylactic strategy introduced to UCH on 1st November 2019

Table

Table 1: Baseline Characteristics

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/safety-and-efficacy-of-apixaban-as-thromboprophylaxis-in-multiple-myeloma-patients-receiving-chemotherapy-a-prospective-cohort-study/