TINzaparin Prophylaxis in Patients With Metastatic Colorectal Cancer

This research study is a prospective, randomized, open label (PROBE), non placebo-controlled, and phase III clinical trial; Investigator Initiated Study (IIS). The study has been considered a low-interventional clinical trial. The trial will compare the efficacy and safety of tinzaparin with a watch and wait strategy for primary prophylaxis of symptomatic or incidental VTE in adult men and women, 18 years of age and older, with metastatic colorectal cancer who are scheduled to initiate systemic cancer therapy as a component of their standard of care anticancer regimen. The study consists of 3 periods: a 4-week screening period, a 4 months treatment period and post-treatment follow-up period until the end of treatment (EOT) visit, scheduled 2 months after the last dose of tinzaparin or 6 months from the first dose of tinzaparin (whichever occurs latest). The duration of participation in the study for each subject is approximately 6 months. Further long-term phone follow-up to monitor for progression and survival could be carried out at the end of study. Tumor follow-up assessments will adhere to the standard clinical practice within each site. All patients will receive the first-line anticancer treatment deemed more appropriate according to the physician criteria and current guideline recommendations. Patients in both groups will receive supportive care as per local practice. No formal recommendations will be issued by the study protocol regarding cancer treatment and supportive care, but the drugs used will be recorded in the clinical report form. Constitutive use of anticoagulant drugs will be prohibited during the treatment period. Enrolled patients are randomized in a 1:1 ratio to the control arm, or the experimental arm: Control arm: A watch and wait strategy will be used. There is no placebo. Since no reference treatment is available for long-term VTE prophylaxis in patients with cancer, patients in the control group will not receive VTE prophylaxis outside the hospital and will receive anticancer treatment and supportive care as per local practice. No formal recommendations will be issued by the study protocol regarding cancer treatment and supportive care, but the drugs used will be recorded in the clinical report form (CRF). Patients in the control group will receive antithrombotic prophylaxis as per local practice during hospitalizations. Any use of LMWH will be recorded in the CRF. Experimental arm: Patients will receive prophylaxis tinzaparin at a fixed dose daily for 4 months. The primary objective is to evaluate the efficacy of 4-months prophylaxis with tinzaparin for the prevention of symptomatic or incidental VTE events. Secondary efficacy objectives include the VTE incidence in specific subpopulations (stratification according to the laterality of the primary tumor, first-line treatment with anti-EGFR or antiangiogenics, and mutational status). Safety of tinzaparin will be evaluated by means of relevant adverse events, incidence of bleedings according to International Society of Thrombosis and Hemostasis (ISTH) criteria, and patient-reported quality of life. Bleeding events will be evaluated locally by the investigator and centrally by a blinded committee.