Our literature search returned 158 unique publications (Figure 1). During the review of titles and abstracts, 136 publications were excluded. A total of 22 full-text articles were reviewed, of which 10 were excluded. Twelve studies were included in this review.
Cancer
Four trials assessed matters of safety for tinzaparin in patients with cancer, including a total of 1,588 patients (Table 1). Tinzaparin was prescribed at a therapeutic dose across all four studies. Bleeding rates ranged between 25.4 and 27%; median major bleeding rate was 3.8%.
The Main LITE trial randomized 200 patients with cancer and symptomatic proximal VTE to receive either tinzaparin or usual care [11]. Bleeding events occurred in 27% of patients; major bleeding occurred in 7%. This study recorded a non-significant decline in bleeding for patients treated with tinzaparin (absolute difference -3.0; 95% CI, -9.1-15.1). All-cause mortality at 12 months was 47% in each group. Romera et al. recorded major bleeding in 0.8% of cancer patients that received tinzaparin versus 2.5% in those who received acenocoumarol for 6 months after the index thromboembolic event (P = .6) [13]. The CATCH trial compared tinzaparin versus conventional therapy (tinzaparin followed by warfarin) for 6 months for the treatment of patients with cancer and proximal DVT or PE [14]. Bleeding events occurred in 25.4% of patients on tinzaparin. Although there was no significant difference in the rates of major bleeding events (12 patients for tinzaparin vs 11 patients for warfarin; HR, 0.89; 95% CI, 0.40-1.99; P = .77), patients receiving tinzaparin had significantly lower rates of clinically relevant nonmajor bleeding events (49 of 449 patients for tinzaparin vs 69 of 451 patients for warfarin; HR, 0.58; 95% CI, 0.40-0.84; P = .004). All-cause mortality on the tinzaparin arm was 69% at 6 months. The TiCAT study assessed the safety of long-term (beyond 6 months) treatment of cancer-associated thrombosis (CAT) with tinzaparin [15]. On this single-arm, multicenter study, 247 cancer patients received therapeutic doses of tinzaparin (175 IU/kg). At 12 months, clinically relevant bleeding events occurred in 18 patients (7.3%), of which 12 (4.9%) were major and 6 (2.4%) were non-major bleeding events. The rate of clinically relevant bleeding events in months 1-6 compared with months 7-12 was 0.9% versus 0.6% patient-months respectively. All-cause mortality at 12 months was 25.1%; the underlying cancer was the main cause of death 90% of the times.
Renal Impairment
Safety of tinzaparin in patients with renal impairment was evaluated in eight studies, including a total of 699 patients (Table 2). A prophylactic regimen was used in two studies; therapeutic doses of tinzaparin were prescribed in six studies. No bioaccumulation effect was noted across all eight studies. While reported major bleeding rates for patients on prophylactic tinzaparin regimens were zero, major bleeding rates ranged from 0 to 2.3% for non-cancer patients and from 4.3 to 10% for cancer patients receiving therapeutic doses of tinzaparin.
A pharmacodynamic study in 55 elderly (age > 75 years) patients with impaired renal function (creatinine clearance [CrCl] was 34.7 +/- 11.4 ml/min; body weight was 52.3 +/- 8.6 kg) showed that there was no significant accumulation effect after eight days of prophylactic administration of tinzaparin [15]. The STRIP study prospectively assessed the risk of bioaccumulation for prophylactic doses of tinzaparin (2500-4500 IU depending on body weight) in 28 patients with severe chronic kidney disease (CKD) [16]. The median estimated glomerular filtration rate (eGFR) of the patients that were enrolled was 16 (ranging from 12 to 25) ml/min/1.73m2. Short-term tinzaparin was not associated with disproportionate anticoagulation; peak anti-Xa levels were below therapeutic range at all time-points and trough anti-Xa levels were undetectable. Also, no major bleeding events were noted.
Pautas et al. investigated matters of safety for therapeutic doses of tinzaparin (175 IU/kg) in 200 elderly inpatients with CrCl above 20 ml/min [17]. In this study the mean age of the participants was 85.2 (ranging from 70 to 102) years and mean CrCl was 51.2 ml/min. One death possibly related to anticoagulation treatment (0.5%), three major bleeding events (1.5%) and two cases of heparin-induced thrombocytopenia (1%) were reported. Interestingly, no correlation was found between measured anti-Xa activity and age or CrCl. The TRIVET study also assessed potential bioaccumulation for therapeutic doses of tinzaparin (175 IU/kg) in 148 patients with acute VTE and different degrees of CKD [18]. Although mean trough anti-Xa levels were significantly higher in patients with CrCl < 30 mL/min and hemodialysis-dependent patients in comparison with patients with CrCl > 60 mL/min (P < .005), measured anti-Xa levels were below the accumulation threshold for all patients. Additionally, there was no accumulation in patients with creatinine clearance < 20 ml/min over time. The IRIS substudy enrolled 87 patients, with a mean age of 83 years (ranging from 75 to 99) and a mean CrCl of 40.8 ml/min, that received tinzaparin (175 IU/kg) for acute VTE [19]. No significant bioaccumulation of tinzaparin was detected. Major bleeding appeared in 2.3% of patients. In addition, tinzaparin accumulation ratio was not correlated with age, weight or CrCl. In 2000, Siguret et al. showed that tinzaparin can be administered safely at a treatment dosage (175 anti-Xa IU/kg) in older patients (age 87.0+/-5.9 years) with age-related renal impairment (creatinine clearance 40.6+/-15.3 mL/min and body weight 62.7+/-14.6 kg) [20] In this study, no major bleeding was reported.
Bauersachs et al. conducted a sub-analysis of the CATCH study to investigate the impact of renal impairment (eGFR < 60 ml/min/1.73m2) on the efficacy and safety of anticoagulation therapy in patients with CAT [21]. There was no significant difference in the rates of either clinically relevant bleeding (14.5% for patients with renal impairment versus 12.7% for patients without renal impairment; RR, 1.14; 95% CI, 0.61-2.16) or major bleeding (4.3% for patients with renal impairment versus 2.5% for patients without renal impairment; RR, 1.72, 95% CI, 0.48-6.17) for patients treated with tinzaparin; patients treated with warfarin exhibited no significant difference in clinically relevant bleeding rates (24.2% for patients with renal impairment versus 15.9% for patients without renal impairment; RR, 1.52; 95% CI, 0.93-2.51) but significant increase in major bleeding rates (8.1% for patients with renal impairment versus 1.6% for patients without renal impairment; RR, 5.06; 95% CI, 1.60-16.14). Lately, Yeung et al. conducted a prospective study on 20 patients with eGFR 20-50 ml/min/1.73m2 and CAT with an indication for therapeutic anticoagulation [22]. Tinzaparin anti-Xa levels were tested at days 2,7 and 14. CrCl was significantly correlated with tinzaparin anti-Xa levels only on day 2; no accumulation of tinzaparin was seen into day 14. Major bleeding occurred in two patients (10%).