Inari Medical Announces Two-Year Interim Results from CLOUT Study, Further Validating Efficacy of ClotTriever System in DVT Treatment

Mar 23, 2024 07:30 CST Updated 07:30

Inari Medical

Cardiovascular Disease Treatment Device Developer

Deep Vein Thrombosis (DVT) of the lower extremities is a disease characterized by abnormal blood clotting in deep veins, leading to impaired blood return. If not properly managed, it may lead to Post-Thrombotic Syndrome (PTS), causing chronic pain, venous ulcers in the lower limbs, and potentially resulting in long-term disability. Traditional DVT treatment involves anticoagulation therapy (AC); however, limitations such as contraindications for anticoagulation, perioperative bleeding risks, and poor efficacy in treating chronic thrombi have restricted its application. There is an urgent need for emerging technologies to advance the comprehensive treatment of DVT. The ClotTriever system, introduced by Inari Medical, is an innovative mechanical thrombectomy device that has received FDA and CE certification. It is specifically designed for DVT treatment and enables rapid and precise removal of thrombi during surgical procedures.

On March 12, 2024, Inari Medical, Inc. recently announced the two-year interim data from the CLOUT registry study, confirming the safety, efficacy, and long-term outcomes of the ClotTriever system in real-world patients with deep vein thrombosis (DVT). In the interim analysis, 228 patients completed the two-year follow-up. Patients showed significant and sustained improvement in post-thrombotic syndrome (PTS) during the follow-up period, with 7.3% of patients experiencing moderate to severe PTS at the two-year mark. The company stated that the reported incidence of PTS was significantly lower than historical DVT studies such as ATTRACT (18%) and CAVA (24%). This further confirms the advantages of the ClotTriever system in practical applications for DVT patients.

CLOUT Study

The CLOUT study is a prospective, multicenter large-scale registry study involving 500 participants, designed to evaluate the safety and efficacy of treatment with the ClotTriever system for lower extremity DVT. Follow-up data at six months showed: the all-cause mortality rate at 30 days post-procedure was 0.9%, with serious adverse events (SAE) occurring in 8.6% of subjects within the first 30 days, one case (0.2%) of which was device-related. The SAE rate of recurrent thrombosis/residual thrombosis was 4.8% at 30 days and 8.0% at six months.

Summary of Key Safety Events Adjudicated by Independent Medical Monitors

ROADSTER 2 Study

Ultrasound detected blood flow within the target vessels significantly increased from 27.2% at baseline to 85.6% at 30 days and 92.5% at 6 months (P < 0.0001). Similarly, the degree of venous compression in the treated segments improved from 28.0% at baseline to 87.6% at 30 days and 91.8% at 6 months (P < 0.0001). The patency rate increased from 17.3% at baseline to 83.5% at 30 days and 88.9% at 6 months (P < 0.0001). Additionally, the median Villalta score improved from 9.0 at baseline to 1.0 at 6 months (P < 0.0001). Vein symptom severity, pain, and quality of life also showed significant improvement.

Ultrasound Outcomes at Baseline, 30 Days, and 6 Months

Baseline to 6-Month PTS Severity Score

Venous Clinical Severity Score, Pain Score, and Quality of Life Score from Baseline to 6 Months

CLOUT Study VS ATTRACT Study

Incorporating data from the CLOUT and ATTRACT studies, patients receiving anticoagulation therapy (AC from ATTRACT) were matched 1:1 with those treated with mechanical thrombectomy (MT from CLOUT) using propensity score matching. Nearest-neighbor matching was performed on nine baseline covariates, including age, body mass index, treated leg, provoked DVT, prior venous thromboembolism, race, gender, Villalta score, and symptom duration. Clinical outcomes, including Villalta score and PTS, were assessed. Logistic regression was used to estimate the likelihood of developing PTS at 12 months.

Research Design Concept

A total of 164 pairs were matched, with no significant differences in baseline characteristics after matching.

Baseline Characteristics of the Anticoagulation and Mechanical Thrombectomy Cohorts Before and After Propensity Score Matching

The MT treatment group had fewer patients with PTS at any location at 6 months (19% vs 46%; P <0.001) and 12 months (17% vs 38%; P <0.001). The model showed that after adjusting for baseline Villalta scores, patients receiving AC treatment had significantly higher odds of developing PTS at any location (odds ratio, 3.1; 95% confidence interval, 1.5-6.2; P <0.002) or moderate to severe PTS (odds ratio, 3.1; 95% confidence interval, 1.1-8.4; P <0.027). Patients receiving MT treatment had lower mean Villalta scores within 12 months compared to those receiving AC treatment (3.3 vs 6.3 at 30 days, 2.5 vs 5.5 at 6 months, and 2.6 vs 4.9 at 12 months; P <0.001).

Comparison of Villalta Scores and PTS Incidence Rates within 12 Months between Anticoagulation Therapy and Mechanical Thrombectomy Groups

RootProbability of PTS within 12 months in the anticoagulation and mechanical thrombectomy cohorts based on Villalta baseline levels

Villalta Score After Cohort Matching

Change in calf swelling from baseline within 30 days

Product Introduction

ClotTriever System is a mechanical thrombectomy device suitable for the treatment of DVT, capable of rapidly and accurately removing thrombus during surgery. The system consists of a retrieval sheath and a thrombectomy catheter, with the thrombectomy catheter being the main component, composed of a core component for capturing thrombus and a collection bag at the rear. The ClotTriever Thrombectomy System is suitable for non-surgical removal of thrombus and emboli in blood vessels, injecting, infusing, and/or aspirating contrast agents and other fluids into blood vessels, and is intended for use in the peripheral vascular system, including deep vein thrombosis (DVT).

Company Introduction

Inari Medical is a commercial-stage medical device company founded in Delaware in July 2011. The company is dedicated to the research and development of catheter technology, striving to provide innovative solutions for the treatment of venous thromboembolism, enabling the safe removal of large amounts of clots from major blood vessels without the use of thrombolytic drugs. ClotTriever is a minimally invasive, mechanical thrombectomy technology system developed by Inari Medical, used for removing clots from peripheral blood vessels and treating DVT.

Reviewed and Edited by: Dr. Chen Xi, Associate Chief Physician, Wuhan First Hospital

Editor: Vascular Information Oliver

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