- Andexanet, the experimental drug may help control serious bleeding associated with patients taking a class of anticoagulants known as Factor Xa inhibitors.
- Factor Xa inhibitors are involved in the formation of blood clots, are commonly prescribed for patients who are at high risk for stroke and venous thrombosis.
- If Andexanet gets approved by the FDA, it would be the first agent available to directly reverse the effects of Factor Xa inhibition if bleeding occurs.
Andexanet has been associated with good control of serious bleeding in patients taking a common class of anticoagulants known as Factor Xa inhibitors, finds a new study. The findings of this study have been discussed at the American College of Cardiology's 67th Annual Scientific Session.
If andexanet gets approved by the FDA, it would be the first drug to directly reverse the action of Factor Xa inhibition if bleeding occurs.
‘Just as how factor Xa inhibitors and other anticoagulants reduce the body's ability to form blood clots, these drugs can also increase the risk of uncontrolled bleeding in case of accidents. Andexanet, the experimental drug could reverse severe bleeding in patients on factor Xa Inhibitor medications.’
Factor Xa inhibitors which are used to inhibit a protein, which is involved in the formation of blood clots. These medications, are Usually prescribed to patients who are at increased risk of stroke and venous thrombosis.
Just as how Factor Xa inhibitors and other anticoagulants reduce the body's ability to form a blood clots. These drugs can also increase the risk of uncontrolled bleeding in case of accidents. In case of road accidents or an emergency, if the bleeding cannot be stopped, patients can die.
"Unlike for some other anticoagulants, there is currently no approved reversal agent for Factor Xa inhibitors," said Stuart Connolly, MD, professor of medicine at McMaster University in Canada and the study's lead author.
"Factor Xa inhibitors are already widely used because of their excellent efficacy and safety profile. However, some physicians and patients may choose to use other anticoagulant drugs because they have a reversal agent rather than using one of the Factor Xa inhibitors. Having a safe and effective reversal agent available will benefit patients with acute bleeding." said the study's lead author.
According to a recent analysis, roughly 84,000 patients taking Factor Xa inhibitor medications are hospitalized for major bleeding issues each year. The common types of major bleeds include bleeding in the brain, sometimes resulting from a fall.
The experimental drug Andexanet is a recombinant modified Factor Xa molecule which is designed to bind to and disable Factor Xa inhibitors and thereby allowing the ever-present Factor Xa to play its normal role in the formation of blood clots.
In previous trials, andexanet has rapidly shown to reverse the anticoagulant effect of Factor Xa inhibitors without any significant safety problems.
ANNEXA-4 is the current clinical trial that uses andexanet to treat patients experiencing major bleeds while they on Factor Xa inhibitors.
The study analysis includes data on safety outcomes of 227 patients and adjudicated efficacy outcomes for 132 patients enrolled at test centers in the U.S., Canada, and Europe.
All trial participants presented with major acute bleeding within 18 hours of taking one of four Factor Xa inhibitors (apixaban, rivaroxaban, edoxaban or enoxaparin). Patients received an injection of andexanet followed by a two-hour infusion of the drug, with the dosage determined based on the specific Factor Xa inhibitor the patient was taking and how long it had been since the last dose.
The trial assesses the drug's efficacy in terms of two co-primary endpoints: reduction in anti-Factor Xa inhibitor activity and achievement of clinical hemostasis (stoppage of bleeding) by 12 hours after administration.
The study results show that the median anti-Factor Xa inhibitor activity was reduced in patients taking certain drugs such as 88 percent rivaroxaban, 91 percent apixaban and 75 percent enoxaparin.
Very few patients in the study received edoxaban. An excellent or good clinical hemostasis was achieved in 83 percent of patients overall.
The Safety of the andexanet drug was assessed in all 227 patients. In the time range of 30 days, 12 percent of patients had died, and 11 percent had a thrombotic event. According to Connolly, these rates of adverse events are in line with what would be expected given the underlying medical condition of the patients in the trial and the fact that many had not resumed anticoagulant treatment during the 30 days after receiving andexanet.
"This study is only focused on patients who are acutely bleeding, but there is also great interest in using a drug like andexanet for patients who come into a medical center on a Factor Xa inhibitor and require urgent surgery, We hope to study that patient population in the future," said Connolly.
The study is not a randomized controlled trial, and it does not include any patients who were not given andexanet (controls). Although a randomized controlled trial offers potentially stronger evidence than a single-arm study design, this method was deemed to be impractical because the drug is intended to be used during crisis situations, demanding a speed of response that could be difficult to achieve with randomization protocols.
- Drug Stops Dangerous Bleeding in Patients Taking Factor Xa Inhibitors - (http://www.acc.org/about-acc/press-releases/2018/03/10/12/18/mon-1045am-drug-stops-dangerous-bleeding-in-patients-taking-factor-xa-inhibitors)