Apixaban Pharmacokinetics in Bariatric Patients (APB)
Condition: Bariatric Surgery; Obesity
Intervention: Apixaban
Intervention description: New Oral Anticoagulants (NOACs) are currently available for prophylaxis against venous thromboembolism in patients undergoing total hip or knee replacement surgery.
Intervention MeSH terms: Apixaban
Phase: Phase 4
Study type: Interventional
Primary purpose: Basic Science
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Enrollment: 33.0
Sex: All
Minimum age: 18 Years
Maximum age: 65 Years
Healthy volunteers: No

Summary:

      The Center for Bariatric Surgery is interested in conducting a pharmacokinetic study of
      apixaban (an oral anticoagulant with FDA approval for use of venous thrombo embolism (VTE)
      prophylaxis and treatment) in the obese adult population to determine if bariatric surgery
      influences apixaban exposure. More interesting would be to see how the dose may need to
      change pre- vs. post-bariatric surgery (this will be important for physicians as more and
      more patients undergo this procedure worldwide and many may require anticoagulation in their
      future healthcare).

      Physicians and surgeons are very interested in oral anticoagulants for this special patient
      population. To date, there is no approved dosing for the obese patient (especially when
      considering surgical intervention such as bariatric surgery).

      Primary outcome variable.

      To determine the durability or change in pharmacokinetics and pharmacodynamics of apixaban in
      patients with a body mass index (BMI) of 35 kg/m2 or greater following one of two bariatric
      surgical procedures (pre-operative versus post-operative vertical sleeve gastrectomy or
      Roux-en-Y gastric bypass patients).

      Secondary outcome variables.

        1. To compare/contrast the pharmacokinetics and pharmacodynamics of apixaban in bariatric
           surgical patients who have undergone RYGB vs. VSG.

        2. To determine how the pharmacokinetics of the drug may differ when there is significant
           post-operative surgical weight loss (>40% estimated excess body weight) 12 to 18 months
           following surgery versus those patients who have suboptimal weight loss following
           bariatric surgery (< 40% of estimated excess body weight).
    

Eligibility criteria:

        Inclusion Criteria:

          -  Men or women, 18 to 65 years old with a BMI of 35 kg/m2 or greater who will be
             undergoing bariatric surgery (VSG and RYGB)

          -  Signed written informed consent

          -  Women of childbearing potential (WOCBP) must have a negative serum or urine pregnancy
             test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 24 hours prior to
             the start of study drug

          -  Women must not be breastfeeding

        Exclusion Criteria:

          -  History of documented clotting/coagulation disorder

          -  History of cancer (within the last year)

          -  Any diagnosis requiring anti-coagulation

          -  History of hypersensitivity reaction to apixaban

          -  Active clinically significant bleeding

          -  Creatinine > 1.5 mg/dL

          -  Participants currently receiving any type of anticoagulation or blood thinning
             medications, including heparin, low molecular weight heparins, Plavix, aspirin, NSAIDS

          -  Participant who is taking any of the excluded medications

               -  Combined P-glycoprotein and strong cytochrome P450 (CYP) 3A4 inhibitor

               -  Combined P-glycoprotein and moderate CYP 3A4 inhibitor

               -  Combined P-glycoprotein inducer and strong CYP 3A4 inducer

               -  Inducers of p-glycoprotein

               -  Strong inducers of CYP 3A4