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Apixaban appears safe, effective for patients with cancer, VTE
Apixaban appeared to serve as a feasible management option for patients with cancer and venous thromboembolism, according to the results of a subgroup analysis from the AMPLIFY trial.
However, further studies are needed to compare apixaban (Eliquis; Bristol-Myers Squibb, Pfizer) with low–molecular-weight heparin, according to the researchers.
Giancarlo Agnelli
“Patients with cancer are prone to developing VTE,” Giancarlo Agnelli, MD, professor of internal medicine and director of the division of internal and cardiovascular medicine at University of Perugia in Umbria, Italy, and colleagues wrote. “High recurrence rates and bleeding complications have been observed when patients with VTE are treated with vitamin K antagonists.”
The AMPLIFY trial compared 6-month courses of oral apixaban and enoxaparin, followed by warfarin, for the treatment of acute VTE. The incidence of recurrent VTE served as the primary endpoint. VTE-related death and major bleeding served as the primary safety endpoints.
Overall, apixaban appeared noninferior to enoxaparin, with fewer bleeding events, according to study background.
Agnelli and colleagues conducted a subgroup analysis of the AMPLIFY trial, which focused on the treatment of VTE in patients with cancer.
The trial included 5,395 patients, 3.1% (n = 169; apixaban, n =88; enoxaparin, n = 81) of whom had active cancer at baseline. An additional 6.8% (n = 365; apixaban, n = 186; enoxaparin, n = 179) had a history of cancer without active cancer.
The most common cancer types included prostate cancer (15.9%), breast cancer (14.8%), colon cancer (12.5%), bladder cancer (8%) and lung cancer (8%).
Among patients with active cancer, three patients assigned apixaban (3.7%) and five patients assigned enoxaparin (6.4%) experienced recurrent VTE (RR = 0.56; 95% CI, 0.13-2.37).
Among patients with a history of cancer, two assigned apixaban (1.1%) and 11 assigned enoxaparin (6.3%) experienced recurrent VTE (RR = 0.17; 95% CI, 0.04-0.78).
Two patients with active cancer (2.3%) assigned apixaban experienced major bleeding, compared with four patients assigned enoxaparin (5%; RR = 0.45; 95% CI, 0.08-2.46).
One patient with a history of cancer assigned apixaban (0.5%) experienced major bleeding, compared with five patients assigned enoxaparin (2.8%; RR = 0.2; 95% CI, 0.02-1.65).
Twenty five patients who were cancer-free at baseline received a cancer diagnosis during the study period (apixaban, n = 13; enoxaparin, n = 12). No patients assigned apixaban who developed cancer experienced recurrent VTE, although one patient experienced major bleeding.
Among patients in the enoxaparin group who developed cancer, four experienced recurrent VTE. The researchers observed one case of major bleeding and one case of clinically relevant nonmajor bleeding.
Among patients with active cancer, 6% assigned apixaban and 7.7% assigned enoxaparin died at 3 months. The corresponding rates among patients with a history of cancer were 1.1% in the apixaban group and 2.9% in the enoxaparin group.
Study limitations included the small sample size and the low reported recurrence rate among patients assigned enoxaparin.
“Many cancer patients with VTE continue to be treated with vitamin K antagonists,” Agnelli and colleagues wrote. “The results of this subgroup analysis suggest that apixaban may be a convenient option for such patients, but additional studies are needed to confirm this concept and to compare apixaban with low–molecular-weight heparin in cancer patients with VTE.” – by Cameron Kelsall
Disclosure: Agnelli and other study researchers report honoraria from and paid consultant roles with Bristol-Myers Squibb and Pfizer. Agnelli further reports personal fees from Bayer Healthcare and Boehringer Ingelheim. Three study researchers report that they are employees of Pfizer. Please see the full study for a list of all other researchers’ relevant financial disclosures.