The API-CALF Study: Apixaban to Treat Calf Vein Thrombosis

• Status: Not yet recruiting
• Trial end date: 2027-08-31
• Target enrollment: 0
• Participant gender: All

Summary

Isolated distal DVT (iDDVT) is the most frequent clinical presentation of VTE and is associated with a significant morbidity and risks of long-term complications. Data from clinical trials highlighted that patients with iDDVT might require some level of AC treatment. However, the optimal anticoagulant intensity is uncertain, and it is plausible that the best benefit/risk ratio for AC might be achieved with lower intensity doses rather than therapeutic doses.

The principal research question of the Apixaban to treat calf vein thrombosis (API-CALF) study is to determine whether, after a conventional course of 7 days of Apixaban 10mg BID, Apixaban 2.5mg BID (experimental arm) is non inferior to Apixaban 5 mg BID (standard arm) in preventing VTE recurrence and bleeding in patients with iDDVT. Patients will be treated with Apixaban for a total of 3 months. In that perspective we will conduct an international multicentre open-label assessor-blinded study

• Phase: Phase 3
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University Hospital, Geneva
• Collaborator: Sunnybrook Health Sciences Centre
• Treatments: Apixaban

Criteria

Inclusion Criteria:

Consecutive patients with acute (symptoms <10 days) symptomatic iDDVT diagnosed on leg CUS who have none of the following exclusion criteria and who provided informed consent to participate. Diagnosis of iDDVT is made in the presence of an incompressible distal deep vein (deep calf vein (posterior tibial, anterior tibial or peroneal veins) or muscular vein (soleal or gastrocnemius veins)).

Exclusion Criteria:

• Age < 18 years

• Ipsi or contralateral Proximal DVT

• Distal DVT involving the tibio-peroneal trunk (i.e. calf trifurcation)

• DVT occurring while on anticoagulation (started ≥48hours before DVT diagnosis); However, inpatients that developed their iDDVT while on prophylactic anticoagulation are eligible if their expected date of discharge is <6 days post randomization.

• Clinically suspected PE (patient eligible if PE ruled out with objective tests)

• Active cancer, receiving cancer treatment or cured for < 6 months

• Indication for long-term therapeutic anticoagulation (e.g. atrial fibrillation, mechanical heart valve…)

• Thrombocytopenia (platelet count <100 g/l)

• Severe renal impairment (creatinine clearance <30 ml/min)

• Liver disease (including Child-Pugh Class B and C) associated with coagulopathy

• Pregnant or breast-feeding woman

• Body weight >120kg or <40 kg

• Ongoing active bleeding or condition at high risk of bleeding with anticoagulation (e.g. peptic ulcer…)

• Treatment with daily NSAIDs (aspirin ≤160 mg/day or clopidogrel ≤75 mg day permitted)

• Allergy to Apixaban

• Use of concomitant drugs that significantly interact with Apixaban: strong inhibitors of P-gp and CYP3A4 or strong inducers of CYP3A4

• Treatment with anticoagulants at therapeutic dose >2 days after DVT diagnosis

• Life expectancy < 1 year

• Enrolled in another clinical trial within previous 30 days

• Inability or refusal to provide informed consent