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NOACs an alternative to LMWHs for cancer-related thromboembolism in Asians

JAMA Network Open
Reuters Health - 12/02/2021 - Non-vitamin K antagonist oral anticoagulants (NOACs) appear to be at least as safe and effective as low-molecular-weight heparins (LMWHs) in Asians with cancer and acute venous thromboembolism (VTE), new research suggests.

As Dr. Wen-Kuan Huang told Reuters Health by email, "NOACs could be a better alternative to LMWHs for treating Asian individuals with cancer-associated VTE. Our study demonstrated that NOACs had similar efficacy but lower gastrointestinal bleeding risk compared with LMWHs."

After their introduction more than a decade ago, NOACs have proved more effective than warfarin in clinical practice for patients with acute VTE, Dr. Huang, of Chang Gung University College of Medicine, in Taoyuan, Taiwan, and colleagues note in JAMA Network Open.

However, they add, it remained uncertain "whether superior clinical benefits were associated with NOACs compared with LMWHs regarding acute VTE in patients with cancer, who have higher rates of recurrent VTE and major bleeding complications on anticoagulation agents."

Moreover, randomized controlled trials have had somewhat conflicting results and "were not specifically designed to examine the effect of NOACs among Asian patients with cancer."

To investigate, the researchers examined data on 1,109 such patients with cancer-associated VTE who were treated between 2012 and 2019. About one-third had lung or colorectal cancer, conditions associated with high thromboembolic risk. Their mean age was 66 years.

In total, 529 patients (47.7%) received NOACs including rivaroxaban, apixaban and edoxaban. The remaining 580 patient received the LMWH enoxaparin.

The composite of recurrent VTE or major bleeding was seen in 75 patients in the NOAC group (14.1%) and 101 patients (17.4%) in the enoxaparin group (P=0.11).

At the 12-month follow-up, the risks of recurrent VTE and major bleeding were 38% (P=0.05) and 20% (P=0.32) lower, respectively, in the NOAC group. Ten patients who took a NOAC had gastrointestinal bleeding compared to 41 patients taking enoxaparin (hazard ratio, 0.29; P<0.001).

Moreover, say the researchers, "the results for effectiveness and safety outcomes remained consistent with the primary analyses after adjusting for death as competing risk, providing further evidence for the robustness of the main findings."

They conclude: "These results suggest that NOACs are associated with effective and safe outcomes as alternatives to LMWHs for the treatment of cancer-associated VTE in Asian patients in real-world practice."

Dr. Christian T. Ruff, director of general cardiology at Brigham and Women's Hospital, in Boston, told Reuters Health by email, "Low-molecular-weight-heparins have long been considered standard of care in the treatment of cancer associated VTE based on relatively modest and outdated trials comparing LMWH to warfarin. Although clinical trials had demonstrated the superior efficacy and safety profile of NOACs compared to warfarin for treatment of VTE there were lingering concerns regarding the generalizability of these data to cancer associated VTE given the relatively small proportion of such patients in the trials and the fact that LMWH and not warfarin was considered the standard of care in these patients."

"These cohort data from Taiwan are in line with recent clinical trials that demonstrate that in general, NOACs are as effective and safe as LMWH in treating cancer associated VTE," said Dr. Ruff, who was not involved in the new work.

"An interesting aspect of this study is that NOACs were associated with a significantly lower rate of gastrointestinal bleeding. These findings are in contrast to clinical trials which found that NOACs were associated with an increase in gastrointestinal bleeding, specifically in patients with a gastrointestinal malignancy. These findings need further study and may be due to differences in patient populations studies," he added.

The study did not have commercial funding, and the researchers report no conflicts of interest.

SOURCE: https://bit.ly/3a3zzod JAMA Network Open, online February 20, 2021.

By David Douglas

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