February 13, 2017
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Adverse events result in high rate of low–molecular-weight heparin discontinuation

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One in five patients with cancer-associated venous thromboembolism discontinued low–molecular-weight heparin injections due to adverse events, according to a prospective, multicenter cohort follow-up study published in Journal of Thrombosis and Haemostasis.

These findings can serve as background information for current clinical trials investigating the efficacy and safety of direct-oral anticoagulants compared with low–molecular-weight heparin (LMWH).

“A remarkable finding was that the most common reason for discontinuing LMWH treatment was pain at the injection site, followed by injection site hematoma and allergic reactions,” S.J. Van der Wall, of the department of thrombosis and hemostasis at Leiden University Medical Center in the Netherlands, and colleagues wrote. “In this study, only female sex was found to be associated with discontinuation because of side effects.”

VTE, including deep vein thrombosis and pulmonary embolism, is a frequent complication of cancer and cancer treatment. LMWH therapy for at least 3 to 6 months is recommended as first-line treatment for cancer-associated VTE because of proven superior efficacy to that of conventional vitamin K antagonists, with a comparable risk for bleeding.

Pain and skin hematoma at the injection site are the most common adverse side effects of LMWH self-administered treatments, occurring in up to 90% of patients.

Previous studies showed discontinuation rates varying from 33% to 58% after 3 to 6 months due to complications, such as recurrent VTE, bleeding or death. Furthermore, recent studies reported 11% to 20% of patients with cancer switched to oral anticoagulants within 3 to 6 months.

In their study, Van der Wall and colleagues analyzed data collected from 372 patients (median age, 67 years; 55% men) with cancer-associated VTE being treated at three hospitals in Denmark and one hospital in Spain.

A total of 194 patients (51%) discontinued LMWH treatment within 6 months, including 78 patients (21%; 95% CI, 17-25) who stopped use because of LMWH side effects after a median period of 90 days (interquartile range, 60-120).

Unacceptable pain at the injection site (n = 33; 8.9%) was the most common reason for discontinuation because of side effects, followed by large local injection site hematomas (n = 27; 7.3%), allergic reactions (n = 15; 4%) and heparin-induced thrombocytopenia (n = 3; 0.81%). Other reasons for discontinuation included death (28%), recurrent VTE (1.3%), major bleeding events (1.1%), curing of cancer (0.08%) and unknown (0.03%).

Only female sex was found to be significantly associated with premature discontinuation of LMWH (OR = 1.6; 95% CI, 1.03-2.5).

Researchers noted that because four of five patients continued with LMWH injections, it may be considered “an acceptable trade-off” against the reported higher risk for recurrent VTE associated with vitamin K antagonists.

“The recently introduced nonvitamin K–dependent oral anticoagulants have the potential to be a valid alternative option for these patients, as these drugs share practical advantages with LMWH, are administered orally, and show a similar efficacy to that of vitamin K antagonists but a lower bleeding risk in phase 3 studies in the general VTE population,” Van der Wall and colleagues wrote. – by Chuck Gormley

Disclosure: The study was supported by an independent research grant from Aspen Pharmaceuticals. One researcher reports grants from Bayer, Boehringer Ingelheim, Bristol-Myers Squibb and Daiichi Sankyo.