2025 Southeastern Residency Conference

EFFECTIVENESS OF PARTIAL VS. FULL-LEAD-IN APIXABAN IN ACUTE VTE AFTER INITIAL PARENTERAL THERAPY


Background: Apixaban, a direct oral anticoagulant (DOAC), is commonly used to treat venous thromboembolism (VTE). The AMPLIFY trial established a seven-day apixaban lead-in regimen following parenteral therapy for acute VTE treatment, but clinical practice often results in extended parenteral anticoagulation preceding apixaban exposure, creating uncertainty regarding optimal apixaban lead-in strategies. A partial lead-in regimen, where apixaban completes the full seven-day regimen including days of parenteral therapy, contrasts with the full lead-in regimen of seven days of apixaban regardless of prior parenteral treatment duration. The impact of these diverse strategies on bleeding and VTE recurrence risk is not well understood. This study aimed to evaluate whether a full apixaban lead-in regimen increases bleeding risk compared to a partial apixaban lead-in regimen in patients with VTE.


Methodology: This was a single-center, retrospective chart review of patients who were started on high dose apixaban 10 mg twice daily after more than 36 hours of parenteral anticoagulation for VTE treatment between August 2015 and September 2024. Patients were included in the full lead-in group if they were ordered 7 days of high dose apixaban after parenteral anticoagulation and patients were included in the partial lead-in group if they were ordered enough high dose apixaban doses to completed 7 full days of anticoagulation, started by the parenteral anticoagulants. The primary outcome was the incidence of major bleeding as defined by the ISTH guidelines. Secondary outcomes included non-major bleeding, readmission for bleeding, and medical contact for VTE recurrence or bleeding within 90 days. 


Results: 418 patients were screened and 61 were included in the study. A total of 58 patients were assigned to the full lead-in group and 8 patients to the partial lead-in group. The primary outcome of incidence of major bleeding was seen in 2 (3.8%) patients in the full lead-in group and 2 (25%) patients in the partial lead-in group (P= 0.247). The secondary outcome of readmission for bleeding was seen in 2 (3.8%) patients on the full lead-in group and 1 (12.5%) patient in the partial lead-in group (P=0.349). Medical contact for VTE recurrence or bleeding within 90 days was not present in either group. 


Conclusions: This study found that real world prescribing practices favors the full lead-in apixaban therapy dosing strategy. The full lead-in group did not show a higher rate of ISTH major bleeding. However, the small sample size, especially in the partial lead-in group, limits conclusions. Larger studies and randomized controlled trials are needed to establish the real safety and efficacy of these two dosing strategies.