Dalteparin is a low molecular weight heparin with antithrombotic properties. It acts by enhancing the inhibition of Factor Xa and thrombin by antithrombin. In man, dalteparin potentiates preferentially the inhibition of coagulation Factor Xa, while only slightly affecting the activated partial thromboplastin time (APTT).
Pharmacodynamics
Doses of FRAGMIN Injection of up to 10,000 anti-Factor Xa IU administered subcutaneously as a single dose or two 5000 IU doses 12 hours apart to healthy subjects do not produce a significant change in platelet aggregation, fibrinolysis, or global clotting tests such as prothrombin time (PT), thrombin time (TT) or APTT. Subcutaneous (s.c.) administration of doses of 5000 IU twice daily of FRAGMIN for seven consecutive days to patients undergoing abdominal surgery did not markedly affect APTT, Platelet Factor 4 (PF4), or lipoprotein lipase.
Pharmacokinetics
Mean peak levels of plasma anti-Factor Xa activity following single s.c. doses of 2500, 5000 and 10,000 IU were 0.19 ± 0.04, 0.41 ± 0.07 and 0.82 ± 0.10 IU/mL, respectively, and were attained in about 4 hours in most subjects. Absolute bioavailability in healthy volunteers, measured as the anti-Factor Xa activity, was 87 ± 6%. Increasing the dose from 2500 to 10,000 IU resulted in an overall increase in anti-Factor Xa AUC that was greater than proportional by about one-third.
Peak anti-Factor Xa activity increased more or less linearly with dose over the same dose range. There appeared to be no appreciable accumulation of anti-Factor Xa activity with twice-daily dosing of 100 IU/kg s.c. for up to 7 days.
The volume of distribution for dalteparin anti-Factor Xa activity was 40 to 60 mL/kg. The mean plasma clearances of dalteparin anti-Factor Xa activity in normal volunteers following single intravenous bolus doses of 30 and 120 anti-Factor Xa IU/kg were 24.6 ± 5.4 and 15.6 ± 2.4 mL/hr/kg, respectively. The corresponding mean disposition half-lives are 1.47 ± 0.3 and 2.5 ± 0.3 hours.
Following intravenous doses of 40 and 60 IU/kg, mean terminal half-lives were 2.1 ± 0.3 and 2.3 ± 0.4 hours, respectively. Longer apparent terminal half-lives (3 to 5 hours) are observed following s.c. dosing, possibly due to delayed absorption. In patients with chronic renal insufficiency requiring hemodialysis, the mean terminal half-life of anti-Factor Xa activity following a single intravenous dose of 5000 IU FRAGMIN was 5.7 ± 2.0 hours, i.e. considerably longer than values observed in healthy volunteers, therefore, greater accumulation can be expected in these patients.
CLINICAL TRIALS
Prophylaxis of Ischemic Complications in Unstable Angina and Non-Q-Wave Myocardial
Infarction
In a double-blind, randomized, placebo-controlled clinical trial, patients who recently experienced unstable angina with EKG changes or non-Q-wave myocardial infarction (MI) were randomized to FRAGMIN Injection 120 IU/kg every 12 hours subcutaneously (s.c.) or placebo every 12 hours s.c. In this trial, unstable angina was defined to include only angina with EKG changes. All patients, except when contraindicated, were treated concurrently with aspirin (75 mg once daily) and beta blockers. Treatment was initiated within 72 hours of the event (the majority of patients received treatment within 24 hours) and continued for 5 to 8 days. A total of 1506 patients were enrolled and treated; 746 received FRAGMIN and 760 received placebo. The mean age of the study population was 68 years (range 40 to 90 years) and the majority of patients were white (99.7%) and male (63.9%). The combined incidence of the double endpoint of death or myocardial infarction was lower for FRAGMIN compared with placebo at 6 days after initiation of therapy. These results were observed in an analysis of all-randomized and all-treated patients. The combined incidence of death, MI, need for intravenous (i.v.) heparin or i.v. nitroglycerin, and revascularization was also lower for FRAGMIN than for placebo (see Table 1).
Table 1
Efficacy of FRAGMIN in the Prophylaxis of Ischemic Complications in Unstable
Angina and Non-Q-Wave Myocardial Infarction
| |
Dosing Regimen |
| Indication |
FRAGMIN
120 IU/kg/every 12 hr s.c. n (%) |
Placebo
every 12 hr s.c. n (%) |
| All Treated Unstable Angina and Non-Q-Wave MI Patients |
746 |
760 |
| Primary Endpoints - 6 day timepoint Death, MI |
13/741 (1.8)1 |
36/757 (4.8) |
| Secondary Endpoints - 6 day timepoint Death, MI, i.v. heparin, i.v. nitroglycerin,
Revascularization |
59/739 (8.0)1 |
106/756 (14.0) |
| 1 p-value = 0.001 |
In a second randomized, controlled trial designed to evaluate long-term treatment
with FRAGMIN (days 6 to 45), data were also collected comparing 1-week (5 to
8 days) treatment of FRAGMIN 120 IU/kg every 12 hours s.c. with heparin at an
APTT-adjusted dosage. All patients, except when contraindicated, were treated
concurrently with aspirin (100 to 165 mg per day). Of the total enrolled study
population of 1499 patients, 1482 patients were treated; 751 received FRAGMIN
and 731 received heparin. The mean age of the study population was 64 years
(range 25 to 92 years) and the majority of patients were white (96.0%) and male
(64.2%). The incidence of the combined triple endpoint of death, myocardial
infarction, or recurrent angina during this 1-week treatment period (5 to 8
days) was 9.3% for FRAGMIN and 7.6% for heparin (p=0.323).
Prophylaxis of Deep Vein Thrombosis in Patients Following Hip Replacement
Surgery
In an open-label randomized study, FRAGMIN 5000 IU administered once daily s.c. was compared with warfarin sodium, administered orally, in patients undergoing hip replacement surgery. Treatment with FRAGMIN was initiated with a 2500 IU dose s.c. within 2 hours before surgery, followed by a 2500 IU dose s.c. the evening of the day of surgery. Then, a dosing regimen of FRAGMIN 5000 IU s.c. once daily was initiated on the first postoperative day. The first dose of warfarin sodium was given the evening before surgery, then continued daily at a dose adjusted for INR 2 to 3. Treatment in both groups was then continued for 5 to 9 days postoperatively. Of the total enrolled study population of 580 patients, 553 were treated and 550 underwent surgery. Of those who underwent surgery, 271 received FRAGMIN and 279 received warfarin sodium. The mean age of the study population was 63 years (range 20 to 92 years) and the majority of patients were white (91.1%) and female (52.9%). The incidence of deep vein thrombosis (DVT), any vein, as determined by evaluable venography, was significantly lower for the group treated with FRAGMIN compared with patients treated with warfarin sodium (28/192 vs 49/190; p=0.006) (see Table 2).
Table 2
Efficacy of FRAGMIN in the Prophylaxis of Deep Vein Thrombosis Following
Hip Replacement Surgery
| |
Dosing Regimen |
| Indication |
FRAGMIN
5000 IU once daily1 s.c. n (%) |
Warfarin
Sodium once daily 2 oral n (%) |
| All Treated Hip Replacement Surgery Patients |
271 |
279 |
| Treatment Failures in Evaluable Patients DVT, Total |
28/192 (14.6)3 |
49/190 (25.8) |
| Proximal DVT |
10/192 (5.2)4 |
16/190 (8.4) |
| PE |
2/271 (0.7) |
2/279 (0.7) |
1 The daily dose on the day of surgery
was divided: 2500 IU was given two hours before surgery and again in the
evening of the day of surgery.
2 Warfarin sodium dosage was adjusted to maintain
a prothrombin time index of 1.4 to 1.5, corresponding to an International
Normalized Ratio (INR) of approximately 2.5.
3 p-value = 0.006
4 p-value = 0.185 |
In a second single-center, double-blind study of patients undergoing hip replacement
surgery, FRAGMIN 5000 IU once daily s.c. starting the evening before surgery,
was compared with heparin 5000 U s.c. three times a day starting the morning
of surgery. Treatment in both groups was continued for up to 9 days postoperatively.
Of the total enrolled study population of 140 patients, 139 were treated and
136 underwent surgery. Of those who underwent surgery, 67 received FRAGMIN and
69 received heparin. The mean age of the study population was 69 years (range
42 to 87 years) and the majority of patients were female (58.8%). In the intent-to-treat
analysis, the incidence of proximal DVT was significantly lower for patients
treated with FRAGMIN compared with patients treated with heparin (6/67 vs 18/69;
p=0.012). Further, the incidence of pulmonary embolism detected by lung scan
was also significantly lower in the group treated with FRAGMIN (9/67 vs 19/69;
p=0.032).
A third multi-center, double-blind, randomized study evaluated a postoperative dosing regimen of FRAGMIN for thromboprophylaxis following total hip replacement surgery. Patients received either FRAGMIN or warfarin sodium, randomized into one of three treatment groups. One group of patients received the first dose of FRAGMIN 2500 IU s.c. within 2 hours before surgery, followed by another dose of FRAGMIN 2500 IU s.c. at least 4 hours (6.6 ± 2.3 hr) after surgery. Another group received the first dose of FRAGMIN 2500 IU s.c. at least 4 hours (6.6 ± 2.4 hr) after surgery. Then, both of these groups began a dosing regimen of FRAGMIN 5000 IU once daily s.c. on postoperative day 1. The third group of patients received warfarin sodium the evening of the day of surgery, then continued daily at a dose adjusted for INR 2 to 3. Treatment for all groups was continued for 4 to 8 days postoperatively, after which time all patients underwent bilateral venography.
In the total enrolled study population of 1501 patients, 1472 patients were treated; 496 received FRAGMIN (first dose before surgery), 487 received FRAGMIN (first dose after surgery) and 489 received warfarin sodium. The mean age of the study population was 63 years (range 18 to 91 years) and the majority of patients were white (94.4%) and female (51.8%).
Administration of the first dose of FRAGMIN after surgery was as effective in reducing the incidence of thromboembolic events as administration of the first dose of FRAGMIN before surgery (44/336 vs 37/338; p=0.448). Both dosing regimens of FRAGMIN were more effective than warfarin sodium in reducing the incidence of thromboembolic events following hip replacement surgery.
Prophylaxis of Deep Vein Thrombosis Following Abdominal Surgery in Patients
at Risk for Thromboembolic Complications
Abdominal surgery patients at risk include those who are over 40 years of age, obese, undergoing surgery under general anesthesia lasting longer than 30 minutes, or who have additional risk factors such as malignancy or a history of deep vein thrombosis or pulmonary embolism.
FRAGMIN administered once daily s.c. beginning prior to surgery and continuing for 5 to 10 days after surgery, was shown to reduce the risk of DVT in patients at risk for thromboembolic complications in two double-blind, randomized, controlled clinical trials performed in patients undergoing major abdominal surgery. In the first study, a total of 204 patients were enrolled and treated; 102 received FRAGMIN and 102 received placebo. The mean age of the study population was 64 years (range 40 to 98 years) and the majority of patients were female (54.9%). In the second study, a total of 391 patients were enrolled and treated; 195 received FRAGMIN and 196 received heparin. The mean age of the study population was 59 years (range 30 to 88 years) and the majority of patients were female (51.9%). As summarized in the following tables, FRAGMIN 2500 IU was superior to placebo and similar to heparin in reducing the risk of DVT (see Tables 3 and 4).
Table 3
Efficacy of FRAGMIN in the Prophylaxis of Deep Vein Thrombosis Following
Abdominal Surgery
| |
Dosing Regimen |
| Indication |
FRAGMIN
2500 IU once daily s.c. n (%) |
Placebo
Once daily s.c. n (%) |
| All Treated Abdominal Surgery Patients |
102 |
102 |
| Treatment Failures in Evaluable Patients Total Thromboembolic Events |
4/91 (4.4)1 |
16/91 (17.6) |
| Proximal DVT |
0 |
5/91 (5.5) |
| Distal DVT |
4/91 (4.4) |
11/91 (12.1) |
| PE |
0 |
2/91 (2.2)2 |
1 p-value = 0.008
2 Both patients also had DVT, 1 proximal and
1 distal |
Table 4
Efficacy of FRAGMIN in the Prophylaxis of Deep Vein Thrombosis Following
Abdominal Surgery
| |
Dosing Regimen |
| Indication |
FRAGMIN
2500 IU once daily s.c. n (%) |
Heparin
5000 U twice daily s.c. n (%) |
| All Treated Abdominal Surgery Patients |
195 |
196 |
| Treatment Failures in Evaluable Patients Total Thromboembolic Events |
7/178 (3.9)1 |
7/174 (4.0) |
| Proximal DVT |
3/178 (1.7) |
4/174 (2.3) |
| Distal DVT |
3/178 (1.7) |
3/174 (1.7) |
| PE |
1/178 (0.6) |
0 |
| 1 p-value = 0.74 |
In a third double-blind, randomized study performed in patients undergoing major abdominal surgery with malignancy, FRAGMIN 5000 IU once daily was compared with FRAGMIN 2500 IU once daily. Treatment was continued for 6 to 8 days. A total of 1375 patients were enrolled and treated; 679 received FRAGMIN 5000 IU and 696 received 2500 IU. The mean age of the combined groups was 71 years (range 40 to 95 years). The majority of patients were female (51.0%). The study showed that FRAGMIN 5000 IU once daily was more effective than FRAGMIN 2500 IU once daily in reducing the risk of DVT in patients undergoing abdominal surgery with malignancy (see Table 5).
Table 5
Efficacy of FRAGMIN in the Prophylaxis of Deep Vein Thrombosis Following
Abdominal Surgery
| |
Dosing Regimen |
| Indication |
FRAGMIN
2500 IU once daily s.c. n (%) |
FRAGMIN
5000 IU once daily s.c. n (%) |
| All Treated Abdominal Surgery Patients1 |
696 |
679 |
| Treatment Failures in Evaluable Patients Total Thromboembolic Events |
99/656 (15.1)2 |
60/645 (9.3) |
| Proximal DVT |
18/657 (2.7) |
14/646 (2.2) |
| Distal DVT |
80/657 (12.2) |
41/646 (6.3) |
| PE Fatal |
1/674 (0.1) |
1/669 (0.1) |
| Non-fatal |
2 |
4 |
1 Major abdominal surgery with malignancy
2 p-value = 0.001 |
Prophylaxis of Deep Vein Thrombosis in Medical Patients at Risk for Thromboembolic
Complications Due to Severely Restricted Mobility During Acute Illness
In a double-blind, multi-center, randomized, placebo-controlled clinical trial, general medical patients with severely restricted mobility who were at risk of venous thromboembolism were randomized to receive either FRAGMIN 5000 IU or placebo s.c. once daily during Days 1 to 14 of the study. The primary endpoint was evaluated at Day 21, and the follow-up period was up to Day 90. These patients had an acute medical condition requiring a projected hospital stay of at least 4 days, and were confined to bed during waking hours. The study included patients with congestive heart failure (NYHA Class III or IV), acute respiratory failure not requiring ventilatory support, and the following acute conditions with at least one risk factor occurring in > 1% of treated patients: acute infection (excluding septic shock), acute rheumatic disorder, acute lumbar or sciatic pain, vertebral compression, or acute arthritis of the lower extremities. Risk factors include > 75 years of age, cancer, previous DVT/PE, obesity and chronic venous insufficiency. A total of 3681 patients were enrolled and treated: 1848 received FRAGMIN and 1833 received placebo. The mean age of the study population was 69 years (range 26 to 99 years), 92.1% were white and 51.9% were female. The primary efficacy endpoint was defined as at least one of the following within Days 1 to 21 of the study: asymptomatic DVT (diagnosed by compression ultrasound), a confirmed symptomatic DVT, a confirmed pulmonary embolism or sudden death.
When given at a dose of 5000 IU once a day s.c. FRAGMIN significantly reduced the incidence of thromboembolic events including verified DVT by Day 21 (see Table 6). The prophylactic effect was sustained through Day 90.
Table 6
Efficacy of FRAGMIN in the Prophylaxis of Deep Vein Thrombosis in Medical
Patients with Severely Restricted Mobility During Acute Illness
| |
Dosing Regimen |
| Indication |
FRAGMIN
5000 IU once daily s.c. n (%) |
Placebo
Once daily s.c. n (%) |
| All Treated Medical Patients During Acute Illness |
1848 |
1833 |
Treatment failure in evaluable patients (Day 21)1
DVT, PE, or sudden death |
42/1518 (2.8)2 |
73/1473 (5.0) |
| Total thromboembolic events (Day 21) |
37/1513 (2.5) |
70/1470 (4.8) |
| Total DVT |
32/1508 (2.1) |
64/1464 (4.4) |
| Proximal DVT |
29/1518 (1.9) |
60/1474 (4.1) |
| Symptomatic VTE |
10/1759 (0.6) |
17/1740 (1.0) |
| PE |
5/1759 (0.3) |
6/1740 (0.3) |
| Sudden Death |
5/1829 (0.3) |
3/1807 (0.2) |
1Defined as DVT (diagnosed by compression ultrasound
at Day 21 + 3), confirmed symptomatic DVT, confirmed PE or sudden death.
2 p-value = 0.0015 |
Patients with Cancer and Acute Symptomatic Venous Thromboembolism
In a prospective, multi-center, open-label, clinical trial, 676 patients with
cancer and newly diagnosed, objectively confirmed acute deep vein thrombosis
(DVT) and/or pulmonary embolism (PE) were studied. Patients were randomized
to either Fragmin 200 IU/kg (max 18,000 IU/ s.c. daily for one month) then 150
IU/kg (max 18,000 IU s.c. daily) for five months (FRAGMIN arm) or FRAGMIN 200
IU/kg (max 18,000 IU s.c. daily) for five to seven days and oral anticoagulant
for six months (OAC arm). In the OAC arm, oral anticoagulation was adjusted
to maintain an INR of 2 to 3. Patients were evaluated for recurrence of symptomatic
venous thromboembolism (VTE) every two weeks for six months.
The median age of patients was 64 years (range: 22 to 89 years); 51.5% of patients
were females; 95.3% of patients were Caucasians. Types of tumors were: breast
(16%), lung (13.3%), gastrointestinal tract (23.7%), genito-urinary (21.5%),
hematological tumors (10.4%) or other tumors (15.1%). Venous thrombotic events
were adjudicated by a blinded central committee.
A total of 27 (8.0%) and 53 (15.7%) patients in the FRAGMIN and OAC arms, respectively,
experienced at least one episode of an objectively confirmed, symptomatic DVT
and/or PE during the 6-month study period. Most of the difference occurred during
the first month of treatment (see Table 7). The benefit was maintained over
the 6-month study period.
Table 7
Recurrent VTE in Patients with Cancer (Intention to treat population)1
| Study Period |
FRAGMIN arm |
OAC arm |
| |
FRAGMIN 200 IU/kg (max. 18,000 IU) s.c. once daily x 1 month,
then 150 IU/kg (max. 18,000 IU) s.c. once daily x 5 months |
FRAGMIN 200 IU/kg (max 18,000 IU) s.c. once daily x 5 to
7 days and OAC for 6 months (target INR 2.0-3.0 2 to 3) |
| |
Number at Risk |
Patients with VTE |
% |
Number at Risk |
Patients with VTE |
% |
| Total |
338 |
27 |
8.0 |
338 |
53 |
15.7 |
| Week 1 |
338 |
5 |
1.5 |
338 |
8 |
2.4 |
| Week 2-4 |
331 |
6 |
1.8 |
327 |
25 |
7.6 |
| Weeks 5-28 |
307 |
16 |
5.2 |
284 |
20 |
7.0 |
| 1 Three patients in the FRAGMIN arm and 5 patients
in the OAC arm experienced more than 1 VTE over the 6-month study period. |
In the intent-to-treat population that included all randomized patients, the
primary comparison of the cumulative probability of the first VTE recurrence
over the 6-month study period was statistically significant (p=0.0017) in favor
of the FRAGMIN arm, with most of the treatment difference evident in the first
month.
Last updated on RxList: 6/21/2007