The FLEXTRA Trial
Jackson Orthopaedic Foundation participated in a post market study reviewing dosing schedules in a “blood thinning” medication called Arixtra® (generic name: Fondaparinux Sodium). The name given to this study by the pharmaceutical company was FLEXTRA: Flexibility in Administration of Fondaparinux for Prevention of Symptomatic Venous Thromboembolism in Orthopaedic Surgery. (Not to be confused with the drug Flextra-DS: acetaminophen and phenyltoloxamine, which is unrelated to this study.)
The FLEXTRA Trial looked at how well Arixtra® works in preventing blood clots and how safe Arixtra® is if taken more than six hours after elective orthopedic hip and knee surgery. Results
ARIXTRA(R) Administered Morning After Orthopedic Surgery Prevented Venous Thromboembolism With Low Risk Of Bleeding
(From a paper published in the January 2006 issue of The Journal of Arthroplasty)
The primary endpoint of the study was the comparison of tolerability and efficacy of ARIXTRA (2.5 mg) in patients using two different dosing schedules. Patients were randomized into two groups: a standard dosing schedule (first postoperative dose 8 (+/-) 2 hours after surgery) and an alternate dosing schedule (first postoperative dose between 7:00 a.m. and 9:00 a.m. the morning after surgery). Subsequent doses were administered once daily between 7 a.m. and 9 a.m. for a total of 7 to 10 days.
The study included 2,046 patients, 2,000 of whom were evaluated for efficacy (1,003 in the standard-regimen group and 997 in the alternate-regimen group). Both groups were similar for baseline, surgical, and post-surgical characteristics.
Efficacy was similar between the treatment groups in the study. When evaluated 6 (+/-) 2 weeks following surgery, the incidence of VTE, including symptomatic DVT or PE, concurrent DVT and PE, or fatal PE, was similar for both groups (P (>/=) .81). In the standard-regimen group, 19 patients (1.9 percent) experienced VTE compared with 18 patients (1.8 percent) in the alternate-regimen group (P = .89). PE occurred in 9 patients (0.9 percent) in both treatment groups, and no PE-related fatalities occurred. Two patients in the alternate-regimen group experienced both DVT and PE. The median time to first occurrence of VTE following surgery was also similar between groups: 5 days in the standard-regimen group and 7 days in the alternate-regimen group (P = .96).
Additionally, safety results were similarly low for both groups. At 6 (+/-) 1 weeks after surgery, 12 patients (1.2 percent) in the standard-regimen group and 7 patients (0.7 percent) in the alternate-regimen group had a major bleeding episode (P = .24). The incidence of minor bleeding was also low (1.4 percent versus 1.9 percent in the standard-regimen and alternate-regimen groups, respectively; P = .41). Bleeding into a critical organ or death from bleeding did not occur in either group.