Updated Guidance: Use of DOACs in Patients with Venous Thrombosis and Malignant Disease
This is the second in a series of DOAC blogs
Key points:
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The NHSGGC Venous Thrombosis in Malignant Disease guideline has been updated to include apixaban as a treatment option for patients with active malignancy and/or receiving systemic anti-cancer therapy (SACT)/radiotherapy who are diagnosed with venous thromboembolism (VTE).
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Any possible medication interactions between direct oral anticoagulants (DOACs) with SACT should be considered as well as with patients’ other pre-existing medicines. The Cancer Drug Interaction Checker (cancer-druginteractions.org) is a useful source of information in addition to the Summary of Product Characteristics (SPC) and the BNF. As SACT may not be on the emergency care summary (ECS), it’s important to establish what treatment patients are receiving. It is considered good practice to discuss any patients admitted to hospital on SACT with their relevant cancer specialist team.
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Dalteparin remains a treatment option and should continue to be used for patients with platelets less than 50x109/L and for those who are enrolled in a clinical trial where concomitant treatment with a DOAC is contraindicated.
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For those patients on dalteparin, please see the table in the guideline on reducing the dose after one month of treatment and related monitoring requirements. The dose is not reduced at one month for patients at extremes of body weight.
Background
Evidence
Dalteparin has been the treatment of choice for patients with cancer and/or receiving active treatment for cancer diagnosed with a VTE, however, there is now evidence from randomised controlled trials comparing DOACs against dalteparin. Apixaban has been shown to be non-inferior to dalteparin for the treatment of VTE with no increased risk of major bleeding. Edoxaban has been shown to be non-inferior to dalteparin, however, the rate of major bleeding was significantly higher with edoxaban, a difference driven largely by excess in upper gastrointestinal (GI) bleeding in patients with GI cancers. Rates of recurrent VTE were lower in patients treated with rivaroxaban versus dalteparin, with no significant difference in the rate of major bleeding. There was however a significant increased risk of clinically relevant non-major bleeding in patients treated with rivaroxaban. Furthermore, the rate of major bleeding for patients with gastric or oesophageal cancers was higher with rivaroxaban compared to dalteparin.
Refer to the guideline for further detail on the clinical trials.
Initiation
Therapy should be initiated by the healthcare provider diagnosing the VTE e.g. nurse specialist, doctor. Drug initiation, choice of dose and any initial monitoring will be performed by this provider.
Monitoring
Subsequent responsibility for ongoing monitoring and completion of therapy will rest with the doctor managing the patient’s cancer, usually the oncologist but possibly a specialist respiratory physician, palliative care consultant, or GP. This individual should be identified and consulted prior to patient discharge from the acute care team.
Please ensure the guideline is read in full before prescribing for VTE in this patient group.
The following are commonly asked questions relating to VTE recurrence in patients with malignant disease.
Under what circumstances would a patient be switched to dalteparin from apixaban and vice versa?
As apixaban has been shown to be non-inferior to dalteparin for the treatment of VTE, there is no evidence to suggest that one agent is more effective than another. If VTE recurs on one agent, then the other option should be tried. If VTE recurs on a therapeutic dose of apixaban, switch to dalteparin and prescribe the full therapeutic dose for the duration of treatment.
If a patient has a VTE recurrence whilst on 75% dose of dalteparin (after the first month of treatment), should this be increased back to the full therapeutic dose?
Yes. The full therapeutic dose of dalteparin should be prescribed and the patient should stay on this dose for the duration of treatment. There is no need to switch to an alternative anticoagulant.
Refer to other blogs in the DOAC series:
Safe Prescribing of Direct Oral Anticoagulants (DOACs)
DOAC prescribing and body weight
Look out for future blogs in the DOAC series.
Published: 06/01/2023. Medicines Update blogs are correct at the time of publishing