Switching Drug Therapy for the Prevention of Blood Clot Formation From Enoxaparin to Rivaroxaban After Orthopedic Surgery for Either Total Hip or Total Knee Replacement
Condition: Arthritis; Osteoarthritis, Knee; Osteoarthritis, Hip; Thromboembolism
MeSH terms: Osteoarthritis; Osteoarthritis, Knee; Osteoarthritis, Hip; Thromboembolism
Study type: Interventional
Phase: Phase 3

Summary: 
      The study will describe the short-term effects the study drug, rivaroxaban, has on the body
      when a patient is switched from enoxaparin injection (by needle) to oral rivaroxaban (by
      mouth) for the prevention of blood clotting in the veins after elective total hip or total
      knee replacement surgery. After providing written informed consent, screening procedures will
      be completed to assess eligibility. After enrollment, all patients will be switched from
      enoxaparin to rivaroxaban. Blood samples for the short-term effects of rivaroxaban will be
      taken at various times while in the subacute unit. At the time of discharge, if the study
      doctor feels it is appropriate, an adequate supply of rivaroxaban will be provided to
      complete the full course of therapy. Upon completion of rivaroxaban therapy, all patients
      will be required to have final study procedures performed. Safety evaluations at the final
      visit will include clinical blood laboratory tests, a physical examination, urine pregnancy
      test (if applicable), recording of any adverse events including details regarding any
      bleeding episodes or blood clot events, and assessment of the surgical wound. All patients
      will return any unused study medication and study participation will be complete.
    

Detailed description: 
      The study medication, rivaroxaban, is an oral (by mouth) medication. Rivaroxaban directly
      inhibits one of the clotting mechanisms in the blood that is involved in the formation of
      blood clots in the veins in the body. The ability to inhibit blood clotting will be measured.
      Rivaroxaban is currently approved in the European Union by the European Medicines Agency
      (EMEA) for the prevention of blood clots in veins in orthopedic (bone) surgical patients who
      have had elective total joint (hip or knee) replacement. It is currently under review by the
      Food and Drug Administration (FDA) in the United States for this same indication. Enoxaparin
      is a medication that is injected into the fat tissue under the skin and is approved by the
      FDA for the treatment and prevention of blood clot formation in the veins. The goal of the
      study is to describe the short-term effects that the study drug has on the body when a
      patient is switched from enoxaparin to rivaroxaban. The study hypothesis, or theory, is that
      when switched from enoxaparin to rivaroxaban the ability of the body to inhibit blood
      clotting activity will continue. This is an open-label study which means that all persons
      involved in the study will know what study drug is being given to them. It is a single-arm
      study which means that all patients will be administered the same study medication,
      rivaroxaban. The study will be conducted at large orthopedic centers in the United States.
      All patients will have had elective total hip or total knee replacement surgery. While in the
      hospital, eligible patients will have been receiving enoxaparin either 30 mg twice a day or
      40 mg once daily. Upon discharge from the hospital all eligible patients will require a stay
      in a subacute unit and continuing medication for blood clot prevention. After providing
      written informed consent, patients will have screening procedures completed to determine
      eligibility. Safety evaluations at the screening procedure will include a physical
      examination, vital signs, and clinical blood laboratory tests. Women, who are able to bear
      children, will also have a screening blood pregnancy test performed. A negative pregnancy
      test is needed to be in the study. Just before receiving the first dose of rivaroxaban, 10
      mg, blood sampling for the short-term effects of rivaroxaban will begin and continue at
      various times. All patients will receive 10 mg of rivaroxaban daily. In addition, the study
      doctor will do an assessment of the surgical wound. At the time of discharge from the
      subacute unit, if the study doctor feels it is appropriate, an adequate supply of rivaroxaban
      will be provided to complete the full course of therapy. If a patient withdraws his/her
      consent prior to completion of the study, the appropriate course of blood clot prevention
      therapy will be prescribed by the study doctor. Upon completion of rivaroxaban therapy, all
      patients will be required to have final study procedures performed. Those patients who
      continue oral rivaroxaban after discharge from the subacute unit will be required to return
      for an office visit for final study procedures either at the time of completion of
      rivaroxaban therapy or at the surgical follow-up visit. Patients who have rivaroxaban
      discontinued prior to discharge from the subacute unit will have final study procedures
      completed at that time and a subsequent office visit will not be required. In all cases, the
      prescribed rivaroxaban therapy must have been completed prior to the time of the final visit.
      Safety evaluations at the final visit will include clinical laboratory blood tests, a
      physical examination, urine pregnancy test (if applicable), recording of any adverse events
      including details regarding any bleeding episodes or blood clot events, and assessment of the
      surgical wound. All patients will return any unused study medication and study participation
      will be complete. All patients will receive oral rivaroxaban 10mg daily. First dose of
      rivaroxaban will be given within 2 days after admission to the subacute unit, in the morning
      within 12 hrs (if 30mg twice a day) or 24 hours (if 40mg daily) of the enoxaparin dose.
      Patients will then continue to receive a daily 10 mg dose each morning. The total duration of
      combined therapy (enoxparin plus rivaroxaban) may not exceed 35 days for patients with total
      hip replacement or 14 days with total knee replacement.
    

Intervention name(s): Rivaroxaban
Intervention type(s): Drug
Intervention description(s): 10mg tablet daily, receiving the first dose within two days after admission to the subacute unit. The total duration of combined venous blood clot prevention therapy with enoxaparin and rivaroxaban may not exceed 35 days for patients with total hip replacement or 14 days with total knee replacement
Intervention MeSH terms: Rivaroxaban
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Total Hip Replacement; Total Knee Replacement; Hip Implant; Knee Implant; Joint Prosthesis; Orthopedic Surgery; Rivaroxaban; Xarelto; Blood Clot