Safety and efficacy of apixaban thromboprophylaxis in ambulatory cancer patients according to renal function: a subgroup analysis of the AVERT trial

Background: Apixaban was effective in preventing venous thromboembolism (VTE) in ambulatory cancer patients with Khorana score ≥2 initiating chemotherapy, but with an increased risk of bleeding. Patients with cancer have a higher risk of renal dysfunction, which may be associated with increased risks of thrombotic or bleeding complications. We sought to assess the efficacy and safety of apixaban thromboprophylaxis according to renal function in the AVERT trial. Methods: AVERT trial was a randomized, double‐blinded, placebo‐controlled trial evaluating apixaban as primary thromboprophylaxis for ambulatory cancer patients. The primary efficacy outcome was objectively confirmed VTE within 180 days of randomization. The primary safety outcome was major bleeding events. Results: Among 574 patients randomized, 66 (11.5%) patients had CrCl <60 mL/min and 508 (88.5%) had CrCl ≥60 mL/min. Patients with CrCl <60 mL/min were older, more likely to be female, had lower weight/body mass index, and poorer ECOG performance status. In patients with CrCl <60 mL/min, there were one VTE and one major bleeding event, with no differences in outcomes between apixaban and placebo. In patients with CrCl ≥60 mL/min, apixaban was associated with a significantly lower rate of VTE and overall mortality compared to placebo without an increased risk of bleeding events. The risk of VTE was significantly higher in patients with CrCl ≥60 mL/min. Conclusions: In the AVERT trial, patients with CrCl <60 mL/min did not have higher risk of thrombotic or bleeding complications compared to those with CrCl ≥60 mL/min. (Funded by the CIHR and Bristol‐Myers Squibb‐Pfizer Alliance; NCT02048865).