Rivaroxaban improves clinical outcomes in discharged COVID-19 patients

The multicentre MICHELLE trial found that thromboprophylaxis with rivaroxaban over 5 weeks after discharge was beneficial for COVID-19 patients. Individuals with moderate-to-high risk scores for venous thromboembolism (VTE) showed a 67% risk reduction in a composite of clinical outcomes [1].

“There is a clear indication of in-hospital pharmacological thromboprophylaxis for every patient with COVID-19 after bleeding risk assessment; however, there is no consensus on the role of extended thromboprophylaxis,” stated Prof. Eduardo Ramacciotti (Santa Casa School of Medicine, Brasil) [1–3]. Thus, the MICHELLE trial (NCT04662684) was designed to shed light on a possible advantage of prolonged antithrombotic prophylaxis with rivaroxaban for COVID-19 patients after discharge from hospital [1].

The randomised controlled, open-label study analysed 318 patients that were allocated to treatment with 10 mg of rivaroxaban daily or placebo over 35 days. The enrolled adult COVID-19 patients had previously received a standard-dose thromboprophylaxis during hospital stay of ≥3 days and presented with a thromboembolism risk score of ≥4, or a risk score of 2/3 in combination with an initial D dimer >500 ng/mL in the modified IMPROVE VTE risk score. The primary outcome was a composite of several clinical and imaging-based parameters at day 35 (i.e. symptomatic VTE, VTE-related death, VTE detected at bilateral lower limb venous duplex scan and CT-pulmonary angiogram, symptomatic arterial thromboembolism, myocardial infarction, non-haemorrhagic stroke, major adverse limb event, and cardiovascular death). The baseline characteristics were balanced overall in the study arms. The mean age was between 56.4 and 57.8 years, around 40% were women, and 37.7–38.4% had an IMPROVE VTE score of ≥4.

 The results of the primary outcome revealed a relative risk reduction of 67% for those receiving rivaroxaban (RR 0.33; 95% CI 0.13–0.90; P=0.03) compared with placebo. The corresponding number needed to treat equalled 16. “When we broke down the components of the primary outcome, we could see that the primary outcome occurrence was basically driven by pulmonary embolism, either asymptomatic or symptomatic, and fatal pulmonary embolism in the control group,” said Prof. Ramacciotti. Regarding safety, no major bleedings happened in either study arm, and event rates were low in both groups, even for a composite of adverse consequences due to major, non-major, and other bleedings (rivaroxaban 2.51%; placebo 1.89%).

 “In patients discharged after hospitalisation due to COVID-19 with increased IMPROVE VTE score, thromboprophylaxis with rivaroxaban 10 mg once daily for 35 days improved clinical outcomes without increasing bleeding, compared with no out-of-hospital anticoagulation,” Prof. Ramacciotti concluded.

1. 
   
   1. Ramacciotti E. The Michelle trial: Medically ill hospitalised patients for COVID-19 thrombosis extended prophylaxis with rivaroxaban therapy. Late-breaking trials – COVID 19, ESC Congress 2021, 27–30 August.
   
   
   2. Spyropoulos AC, et al. J Thromb Haemost. 2020;18(8):1859–1865.
   
   
   3. Moores LK, et al.Chest. 2020;158(3):1143–1163.

 

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Posted on 26 October 2021