Hypothesis #1: The 6-month rate of major and clinically relevant non-major bleeding in MM patients receiving IMiDs who are prescribed apixaban 2.5 mg orally twice daily for primary prevention of VTE will be ≤3% (2). Although the MM population, in general, has a higher medical acuity than that of the previous large randomized controlled trials of apixaban, we will be selecting a stable population of MM patients who are appropriate for immunomodulatory therapy.