FRAGMIN 5.000 IU Solution for injection Ref.[10843] Active ingredients: Dalteparin

ATC Code B01AB04: Antithrombotics

Dalteparin sodium is a low molecular weight heparin fraction (weight average molecular weight of 6000 Daltons (range between 5,600 and 6,400 Daltons)) produced from porcine-derived heparin sodium.

Mechanism of action

Dalteparin sodium is an antithrombotic agent, which acts mainly through its ability to potentiate the inhibition of Factor Xa and thrombin by antithrombin. It has a relatively higher ability to potentiate Factor Xa inhibition than to prolong plasma clotting time (APTT).

Pharmacodynamic effects

Compared with standard, unfractionated heparin, dalteparin sodium has a reduced adverse effect on platelet function and platelet adhesion, and thus has only a minimal effect on primary haemostasis. Still some of the antithrombotic properties of dalteparin sodium are thought to be mediated through the effects on vessel walls or the fibrinolytic system.

Clinical efficacy and safety

In a randomised, actively controlled, double-blind trial in 1500 patients undergoing hip replacement surgery (North American Fragmin Trial), both pre-operative and post-operative Fragmin were found to be superior to warfarin (see table below). There was a numerical superiority for pre-operative Fragmin over post-operative Fragmin. Thus in patients where the risk of bleeding is perceived to be too great for pre-operative Fragmin administration other means of reducing thromboembolic risk such as post-operative Fragmin administration may be considered.

Incidence of verified thromboembolic events in ITT efficacy population within 6 ± 2 post-operative days.

^* p <0.001 vs. warfarin (Cochran-Mantel-Haenszel test, two-sided)

Abbreviations: n/N = number of patients affected/number of efficacy-evaluable patients; post-op. = treatment at earliest 4 hours after surgery; pre-op. = treatment within 2 hours before surgery.

In a randomised; placebo-controlled double-blind trial (PREVENT) in 3700 patients with acute medical conditions requiring a projected stay in hospital of >4 days and with recent (<3 days) immobilisation (defined as patients mainly confined to bed during waking hours), the incidence of clinically relevant thromboembolic events was reduced by 45% in patients randomised to receive Fragmin compared with those who received placebo. The incidence of the events comprising the primary endpoint was 2.77% compared with 4.96% in placebo treated patients (difference: - 2.19; 95% CI: - 3.57 to – 0.81; p=0.0015. Therefore, a clinically meaningful reduction in the risk of venous thromboembolism was seen in this study.

The randomized, open-label, controlled, multicenter CLOT study (Randomized Comparison of Low-Molecular Weight Heparin Versus Oral Anticoagulant Therapy for Long Term Anticoagulation in Cancer patients with Venous Thomboembolism) compared dalteparin to standard oral anticoagulant (OAC) therapy in the long term treatment of venous thromboembolism (VTE) in 676 patients with active malignancy who had experienced an acute symptomatic VTE (deep venous thrombosis (DVT) and/or a pulmonary embolism (PE)).

Patients were randomized to one of two groups:

• dalteparin arm prescribed at 200 IU/kg/day administered by subcutaneous (SC) injections (maximum 18,000 IU/day) during 1 month, then approximately 150 IU/kg/day from 2nd – 6th month, or
• VKA arm prescribed during 6 months (target INR 2-3), preceded by SC dalteparin 200 IU/kg/day OD (maximum 18,000 IU/day) during 5 to 7 days.

The most frequent diagnoses were: tumors of the gastrointestinal tract and pancreas (23.7%), genitourinary tumors (prostate, testicle, cervix, uterus, ovary and bladder) (21.5%), breast (16.0%), lung (13.3%). 10.4% of patients had haematological malignancies; 75.1% of patients had metastatic disease.

The index VTE event was DVT alone in nearly 70% and PE with or without DVT in 30% of patients.

The primary endpoint was the time to first recurrence of symptomatic VTE (DVT and/or PE) during 6 months.

A total of 27 patients of 338 (8.0%) in the dalteparin arm and 53 patients of 338 (15.7%) in the VKA arm experienced at least one of the events of the composite primary endpoint. A significant 52% risk reduction in VTE recurrence at 6 months was seen with dalteparin (RR= 0.48, 95% CI [0.30-0.77], p=0.0016).

In the dalteparin arm, 19 patients (5.6%) experienced at least one episode of major bleeding compared to 12 patients (3.6%) in the VKA arm. The cumulative probability of experiencing a major bleeding at 6 months was respectively 6.5% and 4.9%, respectively. Any bleeding occurred with a higher frequency in the VKA arm (18.5% VKA vs 13.6% dalteparin). The comparison of the cumulative probability of first bleeding episode for the 2 treatments was of statistical significance in favour of dalteparin treatment (p=0.0487).

There was no significant difference in mortality between the two groups in deaths at 6 and 12 months (131 vs. 137 and 190 vs. 194 in the dalteparin and VKA arms, respectively).

There was no significant difference in the assessment of Quality of Life between the two groups of treatment.

Paediatric population

There is limited safety and efficacy information on the use of dalteparin in paediatric patients. If dalteparin is used in these patients, anti-Xa levels should be monitored.

The largest prospective study investigated the efficacy, safety and relation of dose to plasma anti-Xa activity of dalteparin in prophylaxis and therapy of arterial and venous thrombosis in 48 paediatric patients (Nohe et al, 1999).

Nohe et al (1999) Study Demographics and Trial Design:

In this study, no thromboembolic events occurred in the 10 patients receiving dalteparin for thromboprophylaxis. In the 23 patients given dalteparin for primary antithrombotic therapy of arterial or venous thrombosis, complete recanalization was seen in 7/23 (30%), partial recanalization in 7/23 (30%) and no recanalization in 9/23 (40%). In the 8 patients administered dalteparin for secondary antithrombotic therapy following successful thrombolysis, recanalisation was maintained or improved. In the 5 patients receiving dalteparin for secondary therapy following failed thrombolysis, no recanalization was seen. Minor bleeding, reported in 2/48 children (4%), resolved after dose reduction. Patient platelet counts ranged from 37,000/μl to 574,000/μl. The authors attributed platelet counts below normal (150,000/μl) to immunosuppressive therapy. A reduction in platelet count ≥50% of the initial value, a sign of heparin-induced thrombocytopenia type 2 (HIT 2), was not observed in any patient. For both prophylaxis and therapy groups, the dalteparin doses (anti-Xa IU/kg) required to achieve target anti-Xa activities (IU/ml) were inversely related to age (r²=0.64, P=0.017; r²=0.13, P=0.013). The predictability of the anticoagulant effect with weight-adjusted doses appears to be reduced in children compared to adults, presumably due to altered plasma binding (see section 5.2).