P139 | A RETROSPECTIVE STUDY COMPARING DOACS VERSUS ASA AS PROPHYLAXIS OF MAJOR THROMBOTIC EVENTS IN LENALIDOMIDE EXPOSED MULTIPLE MYELOMA PATIENTS

Immunomodulatory drugs (e.g., lenalidomide), which are currently the backbone of MM therapy, are strongly associated to venous TE and aspirin (ASA) has been usually administered prophylactically in this setting. However, controversies exist on the benefit of ASA, given the still non-negligible rate of TE registered despite its use. Direct oral anticoagulants (DOACs) may represent an alternative, but data are currently lacking. To gain more insight into this, we enrolled 17 MM patients, diagnosed and treated at Policlinico Tor Vergata of Rome (Italy), with lenalidomide-base regimens who were given ASA or DOACs as thromboprophylaxis. Prophylaxis choice was based on history of TE, patient’s compliance, and TE risk evaluated using IMPEDE and SAVED scores. Incidence of major TE and bleeding related to thromboprophylaxis were evaluated according to the ISTH BATH score. Overall, the median age of our cohort was 73 years (range 59–78) with a 3.25 M/F ratio. Nine patients had a history of TE and were considered eligible for low molecular weight heparin (LMWH) but, due to poor compliance, shifted to DOACs. The rest of the patients (n=8) were given ASA. Among ASA-exposed patients, 25% were low risk (≤ 3), 75% intermediate (4-7), and none high risk (≥ 8), according to the IMPEDE score. Among DOACs-exposed patients, 33.3% and 66.7% qualified intermediate and high risk, respectively. Using SAVED score, 62.5% of ASA-exposed were low risk (0-1), while the remaining 37.5% as high risk (≥ 2). Forty-4.4% and 55.6% of DOACs-exposed were at low and high risk, respectively. ASA-exposed patients had an almost 8-fold higher risk to experience an episode of TE than DOACs-exposed patients (p=0.061, hazard ratio 7.57, 95% confidence intervals 0.91-63.06). Furthermore, DOACs-exposed patients achieved a complete vein recanalization whereas 83% of ASA-exposed did the same. With a median follow-up of 16 months, a single episode of bleeding was observed in 1 patient receiving DOACs (ISTH-BATH score 0) whereas no hemorragic event occurred in the ASA group. Even if in a few patients, we report a trend toward a lower incidence of TE in patients with MM, who are prophylactically exposed to DOACs vs ASA. Our cohort presented a higher thrombotic risk, assessed according to commonly used risk scores, and already suffered from previous TE. Our study provides preliminary evidence of the safety profile and potential advantage of DOACs given as thromboprophylaxis in MM patients receiving lenalidomide.