From the Guidelines
The probability of developing a DVT in a patient with protein C deficiency on Eliquis is significantly reduced, but not entirely eliminated, with an estimated residual risk of approximately 1-3% annually. Eliquis, as a direct oral anticoagulant (DOAC), directly inhibits Factor Xa, thus preventing clot formation regardless of the underlying thrombophilia mechanism, such as protein C deficiency 1. For patients with protein C deficiency, the standard preventive dose of Eliquis (2.5 mg twice daily) or the treatment dose (5 mg twice daily) can reduce the thrombosis risk by approximately 80-90%. Key factors influencing this residual risk include:
- The nature of the protein C deficiency (heterozygous or homozygous), with homozygous deficiencies carrying a higher risk
- The patient's history of previous clots
- Other concurrent risk factors such as immobility, surgery, pregnancy, or additional thrombophilias Given the information from the CARAVAGGIO trial, which compared apixaban (Eliquis) with dalteparin, the incidence of recurrent VTE was numerically lower with apixaban (5.6% versus 7.9%), suggesting that Eliquis is an effective option for reducing the risk of DVT in patients with thrombophilic conditions like protein C deficiency 1. Regular monitoring and strict adherence to the prescribed Eliquis regimen are crucial for maintaining protection against DVT in these patients.
From the Research
Probability of Developing a DVT in a Patient with Protein C Deficiency on Eliquis
- The probability of developing a DVT in a patient with protein C deficiency on Eliquis (apixaban) is not directly stated in the provided studies.
- However, a study 2 reported the clinical outcomes of utilizing apixaban in four patients with systemic thrombosis caused by protein C or S deficiency, and three of the four patients tolerated the apixaban during the follow-up period without any bleeding or thrombotic complications.
- Another study 3 reported a case of a 21-year-old female patient with protein C deficiency who developed DVT of the common femoral vein and was treated with anticoagulant (heparin) and later discharged with oral rivaroxaban.
- A study 4 reviewed the results from preclinical and healthy volunteer studies, large phase III trials evaluating the safety and efficacy of apixaban, and key studies that led to apixaban's current licensing, but did not provide specific data on patients with protein C deficiency.
- A study 5 discussed the clinical management of protein C deficiency, including therapeutic options such as oral anticoagulation with a coumarin derivative or heparin therapy, but did not provide information on the use of apixaban in these patients.
- A study 6 investigated whether apixaban interferes with protein S or activated protein C resistance (factor V Leiden) testing using aPTT-based methods, and found that apixaban did not interfere with the assessment of protein S activity, and APCR testing can distinguish FVL-HET from healthy patients despite apixaban treatment.
Key Findings
- Apixaban may be effective in preventing recurrent thrombotic events in patients with inherited thrombophilia, including protein C deficiency 2.
- Protein C deficiency is a rare disorder associated with an increased risk of developing abnormal blood clots, including DVT 3.
- Apixaban did not interfere with the assessment of protein S activity, and APCR testing can distinguish FVL-HET from healthy patients despite apixaban treatment 6.