New anticoagulants such as Zontivity were developed to replace Coumadin, which for a long time was the standard anticoagulant. Anticoagulants are used to reduce the risk of stroke by preventing the patient’s blood from clotting by thinning it. Because blood doesn't clot as well, when on an anticoagulant medication a patient could be at risk of a severe bleeding event.Patients who take Coumadin have safety nets in place: they regularly have their blood monitored to ensure it stays within therapeutic levels - meaning it will still clot to prevent an uncontrolled bleeding event; and if an uncontrolled bleeding event does occur, the patient can be given vitamin K to reverse the effects of the anticoagulant and get the bleeding under control.
Drug companies manufactured newer anticoagulants to provide patients with a blood thinner that did not require medical monitoring. This would allow patients to use a blood thinner with greater ease and fewer restrictions. But the newer blood thinners are not reversed with vitamin k, meaning patients who suffer an uncontrolled bleeding event could find themselves in a life-threatening situation.
Lawsuits have been filed against the makers of Pradaxa and Xarelto, alleging patients were not adequately warned about the lack of an antidote to the medications.
Zontivity is newer than Pradaxa and Xarelto, having been approved for use in 2014. But its approval did not come without concerns. According to briefing documents from the US Food and Drug Administration (FDA), one study of Zontivity, the TRACER study, was halted early “because of an increased rate of major bleeding, including intracrainial hemorrhage (ICH) in the vorapaxar [Zontivity] arm.”
Meanwhile, a different study, TRA2P, showed positive results for Zontivity, but not without complications.
“There was substantially increased risk of intracranial hemorrhage in the vorapaxar arm subjects with a prior history of stroke coupled with no observed benefit of vorapaxar for the primary endpoint in that subset,” according to the FDA’s briefing documents. In other words, patients with a prior history of stroke had an increased risk of intracranial hemorrhage but received no additional benefit from taking Zontivity.
Lawsuits have been filed against the makers of newer generation anticoagulants alleging patients were not adequately warned about the risks associated with taking the medications, including the risk of uncontrolled bleeding. Lawsuits also allege the drugs were marketed in a misleading way. So far, Zontivity is not one of the drugs facing a lawsuit, but it has been on the market for a very short time.