A study led by researchers from the Rheumatology Research Group of the Vall d'Hebron Research Institute (VHIR) determines that rivaroxaban does not show inferiority compared with vitamin K antagonists for the treatment of antiphospholipid antibody syndrome. The study has been published in https://annals.org/aim/article-abstract/2753019/rivaroxaban-versus-vitamin-k-antagonist-antiphospholipid-syndrome-randomized-noninferiority-trial Annals of Internal Medicine.Antifosfolipid antibody syndrome (SAF) is an autoimmune disorder that is characterized by the presence of antibodies against phospholipid binding proteins. It is manifested by vascular thrombosis (venous or arterial) and obstetric complications, among which include repeat abortions and fetal death during pregnancy. Although different pathogenic mechanisms have been described, long-term anticoagulation with vitamin K (warfarin) antagonists, it is still preferentially and ahead of immunosuppression, the standard treatment for secondary prevention of thrombosis. However, its use can be problematic due to the interactions between foods and medications, hemorrhagic complications and the need for frequent monitoring.The newly available anticoagulation therapies can overcome some of these disadvantages, so it is necessary to compare them. In this line, the researchers, led by Dr. Josefina Cortés-Hernández, head of the Lupus Unit of the Vall d'Hebron University Hospital and the main researcher of the VHIR Rheumatology Research group, designed a non-inferiority study, randomized and lasting three years with the " The objective of determining whether rivaroxaban was less effective than vitamin K antagonists to prevent thrombosis in patients with antiphospholipid antibody syndrome.The first of the objectives that they raised was the effectiveness in the prevention of new thrombotic events. Secondly, they also studied the time and type of thrombosis, the changes in the levels of biomarkers, cardiovascular death and minor bleeding.The study included 190 patients between 18 and 75 years old with antiphospholipid antibody syndrome from 6 hospitals in the State. Vall d'Hebron contributed 95 patients. The patients were randomly assigned to receive rivaroxaban or warfarin adjusted to the dose. After 3 years of follow-up, the proportion of patients with major hemorrhagic events was similar in both groups. There were more events involving stroke in rivaroxaban than in the warfarin group. And, most importantly, they detected practically double the cases of recurrent thrombosis in the rivaroxaban group (11 patients) than in the warfarin group (6 patients). In this sense, as Dr. Josefina Hernández-Cortés "rivaroxaban has not demonstrated non-inferiority to classical anti-vitamin K anticoagulants and their use in these patients, especially those with high thrombotic risk, should not be used." However, "this don't want to say that it should not be given in all the patients. If administered, they should be administered with caution and individually after a correct evaluation by experts in the subject", he concludes.The study received funding from Bayer Hispania and the Catalan Lupus Foundation.