What is the clinical evidence from this study?

Study design: Observational. Population: Cancer-associated thrombosis (n=466). Intervention: Apixaban vs. Placebo. Primary outcome: First episode of objectively documented proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) (aHR 0.49, 95% CI 0.25-0.95, p=<0.05).

September 24, 2020The OncologistOpen Access

D-Dimer Enhances Risk-Targeted Thromboprophylaxis in Ambulatory Patients with Cancer

Q: What are the key findings of this study?

Apixaban reduced venous thromboembolism compared to placebo in ambulatory cancer patients (HR 0.49), and applying a 6-month VTE risk threshold of ≥8% using the CATScore improved the number needed to treat from 17 to 6.

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Key result

Apixaban reduced venous thromboembolism compared to placebo in ambulatory cancer patients (HR 0.49), and applying a 6-month VTE risk threshold of ≥8% using the CATScore improved the number needed to treat from 17 to 6.

Why the study?

Thromboprophylaxis is effective in ambulatory patients with cancer, but uncertainties remain regarding which patients should be targeted.

Does apixaban reduce venous thromboembolism in ambulatory patients with cancer when stratified by a CATScore 6-month VTE risk threshold of ≥8%?

Population

466 ambulatory cancer patients with Khorana Risk Score ≥2 and baseline D-dimer from the AVERT trial

Comparison

Apixaban vs placebo across 6-month VTE risk thresholds (≥8% vs <8%)

Design

Retrospective validation study using randomized trial data

Authors

VKVaibhav KumarUniversity of North Carolina at Chapel Hill JSJoseph R. ShawUniversity of Ottawa NKNigel S. KeyUniversity of North Carolina at Chapel Hill

Discussion

Member takes

Implication

May refine VTE risk stratification in ambulatory cancer; leaves open prospective validation before changing practice.

Study Design

Type

Observational (n=466)

Blinding

Double-blind

Randomization

Randomized

Multicenter

Yes

Structured PICO

Does apixaban reduce venous thromboembolism in ambulatory patients with cancer when stratified by a CATScore 6-month VTE risk threshold of ≥8%?

Population

466 ambulatory patients with cancer and a Khorana Risk Score ≥2 starting chemotherapy, followed for up to 210 days.

Intervention

Apixaban 2.5 mg oral twice daily for up to 180 days

Comparator

Matching placebo for up to 180 days

Outcome

First episode of objectively documented proximal deep vein thrombosis (DVT) or pulmonary embolism (PE)hard clinical

Main Result

Hazard Ratio: 0.49 (95% CI 0.25–0.95)

Absolute Event Rate: 5.5% vs 11.4%

Absolute Risk Reduction: 5.9%

Number Needed to Treat: 17

p-value: p=<0.05

Using a baseline D-dimer-incorporated CATScore to identify a 6-month VTE risk ≥8% highly enriches for ambulatory cancer patients who benefit from apixaban thromboprophylaxis, lowering the number needed to treat to 6.

Limitations

Model performance of the CATScore was assessed only in patients with a Khorana Risk Score ≥2, leaving uncertainty about risk discrimination in lower-risk patients.
Exclusion of 108 randomized patients due to missing baseline D-dimer measurements could introduce selection bias.
Exclusion of patients at high risk of bleeding from the original clinical trial limits generalizability.
Results may not apply to patients receiving immunotherapy, targeted therapy, or hormonal therapy alone.
Potential type II error for overall bleeding in the stratified cohorts due to reduced sample size.
Model performance was assessed only in a cohort of patients with a Khorana Risk Score ≥2
Uncertain if risk discrimination is as robust when applied to a wider cohort of ambulatory patients with cancer with lower baseline predicted risks of VTE (KRS <2)

Cite This Study

Kumar et al. (2020) conducted an observational in Cancer-associated thrombosis (n=466). Apixaban vs. Placebo was evaluated on First episode of objectively documented proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) (aHR 0.49, 95% CI 0.25-0.95, p=<0.05). Apixaban reduced venous thromboembolism compared to placebo in ambulatory cancer patients (HR 0.49), and applying a 6-month VTE risk threshold of ≥8% using the CATScore improved the number needed to treat from 17 to 6.

synapsesocial.com/papers/6a6ddabff44fa9f079dbdf61 https://doi.org/10.1002/onco.13540

Topics

Anticoagulation in AF

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D-Dimer Enhances Risk-Targeted Thromboprophylaxis in Ambulatory Patients with Cancer

Discussion

Member takes

Implication

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Topics

D-Dimer Enhances Risk-Targeted Thromboprophylaxis in Ambulatory Patients with Cancer

Discussion

Member takes

Implication

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Also Consider

Topics

Also Consider