During administration of ARIXTRA, the most common adverse reactions were bleeding complications [see Warnings and Precautions (5.1)].
Hip Fracture, Hip Replacement, and Knee Replacement Surgery: The rates of major bleeding events reported during the hip fracture, hip replacement, or knee replacement surgery clinical trials with ARIXTRA 2.5 mg are provided in Table 2.
Table 2. Bleeding Across Randomized, Controlled Hip Fracture, Hip Replacement, and Knee Replacement Surgery Studies | Peri-Operative Prophylaxis (Day 1 to Day 7 ± 1 post-surgery) | Extended Prophylaxis (Day 8 to Day 28 ± 2 post-surgery) |
ARIXTRA 2.5 mg SC once daily N = 3,616 | Enoxaparin Sodiuma, b N = 3,956 | ARIXTRA 2.5 mg SC once daily N = 327 | Placebo SC once daily N = 329 |
| Major bleedingc | 96 (2.7%) | 75 (1.9%) | 8 (2.4%) | 2 (0.6%) |
| Hip fracture | 18/831 (2.2%) | 19/842 (2.3%) | 8/327 (2.4%) | 2/329 (0.6%) |
| Hip replacement | 67/2,268 (3.0%) | 55/2,597 (2.1%) | — | — |
| Knee replacement | 11/517 (2.1%) | 1/517 (0.2%) | — | — |
| Fatal bleeding | 0 (0.0%) | 1 (<0.1%) | 0 (0.0%) | 0 (0.0%) |
| Non-fatal bleeding at critical site | 0 (0.0%) | 1 (<0.1%) | 0 (0.0%) | 0 (0.0%) |
| Re-operation due to bleeding | 12 (0.3%) | 10 (0.3%) | 2 (0.6%) | 2 (0.6%) |
| BI ≥2d | 84 (2.3%) | 63 (1.6%) | 6 (1.8%) | 0 (0.0%) |
| Minor bleedinge | 109 (3.0%) | 116 (2.9%) | 5 (1.5%) | 2 (0.6%) |
a Enoxaparin sodium dosing regimen: 30 mg every 12 hours or 40 mg once daily.
b Not approved for use in patients undergoing hip fracture surgery.
c Major bleeding was defined as clinically overt bleeding that was (1) fatal, (2) bleeding at critical site (e.g. intracranial, retroperitoneal, intraocular, pericardial, spinal, or into adrenal gland), (3) associated with re-operation at operative site, or (4) with a bleeding index (BI) ≥2.
d BI ≥2: Overt bleeding associated only with a bleeding index (BI) ≥2 calculated as [number of whole blood or packed red blood cell units transfused + [(pre-bleeding) – (post-bleeding)] hemoglobin (g/dL) values].
e Minor bleeding was defined as clinically overt bleeding that was not major.
A separate analysis of major bleeding across all randomized, controlled, peri-operative, prophylaxis clinical studies of hip fracture, hip replacement, or knee replacement surgery according to the time of the first injection of ARIXTRA after surgical closure was performed in patients who received ARIXTRA only post-operatively. In this analysis, the incidences of major bleeding were as follows: <4 hours was 4.8% (5/104), 4 to 6 hours was 2.3% (28/1,196), 6 to 8 hours was 1.9% (38/1,965). In all studies, the majority (≥75%) of the major bleeding events occurred during the first 4 days after surgery.
Abdominal Surgery: In a randomized study of patients undergoing abdominal surgery, ARIXTRA 2.5 mg once daily (n = 1,433) was compared with dalteparin 5,000 IU once daily (n = 1,425). Bleeding rates are shown in Table 3.
Table 3. Bleeding in the Abdominal Surgery Study | ARIXTRA 2.5 mg SC once daily | Dalteparin Sodium 5,000 IU SC once daily |
| N = 1,433 | N = 1,425 |
| Major bleedinga | 49 (3.4%) | 34 (2.4%) |
| Fatal bleeding | 2 (0.1%) | 2 (0.1%) |
| Non-fatal bleeding at critical site | 0 (0.0%) | 0 (0.0%) |
| Other non-fatal major bleeding | | |
| Surgical site | 38 (2.7%) | 26 (1.8%) |
| Non-surgical site | 9 (0.6%) | 6 (0.4%) |
| Minor bleedingb | 31 (2.2%) | 23 (1.6%) |
a Major bleeding was defined as bleeding that was (1) fatal, (2) bleeding at the surgical site leading to intervention, (3) non-surgical bleeding at a critical site (e.g. intracranial, retroperitoneal, intraocular, pericardial, spinal, or into adrenal gland), or leading to an intervention, and/or with a bleeding index (BI) ≥2.
b Minor bleeding was defined as clinically overt bleeding that was not major.
The rates of major bleeding according to the time interval following the first ARIXTRA injection were as follows: <6 hours was 3.4% (9/263) and 6 to 8 hours was 2.9% (32/1112).
Treatment of Deep Vein Thrombosis and Pulmonary Embolism: The rates of bleeding events reported during the DVT and PE clinical trials with the ARIXTRA injection treatment regimen are provided in Table 4.
Table 4. Bleedinga in Deep Vein Thrombosis and Pulmonary Embolism Treatment Studies | ARIXTRA N = 2,294 | Enoxaparin Sodium N = 1,101 | Heparin aPTT adjusted IV N = 1,092 |
| Major bleedingb | 28 (1.2%) | 13 (1.2%) | 12 (1.1%) |
| Fatal bleeding | 3 (0.1%) | 0 (0.0%) | 1 (0.1%) |
| Non-fatal bleeding at a critical site | 3 (0.1%) | 0 (0.0%) | 2 (0.2%) |
| Intracranial bleeding | 3 (0.1%) | 0 (0.0%) | 1 (0.1%) |
| Retro-peritoneal bleeding | 0 (0.0%) | 0 (0.0%) | 1 (0.1%) |
| Other clinically overt bleedingc | 22 (1.0%) | 13 (1.2%) | 10 (0.9%) |
| Minor bleedingd | 70 (3.1%) | 33 (3.0%) | 57 (5.2%) |
a Bleeding rates are during the study drug treatment period (approximately 7 days). Patients were also treated with vitamin K antagonists initiated within 72 hours after the first study drug administration.
b Major bleeding was defined as clinically overt: –and/or contributing to death – and/or in a critical organ including intracranial, retroperitoneal, intraocular, spinal, pericardial, or adrenal gland – and/or associated with a fall in hemoglobin level ≥2 g/dL – and/or leading to a transfusion ≥2 units of packed red blood cells or whole blood.
c Clinically overt bleeding with a 2 g/dL fall in hemoglobin and/or leading to transfusion of PRBC or whole blood ≥2 units.
d Minor bleeding was defined as clinically overt bleeding that was not major.