CALISTO
Trial question
What is the effect of fondaparinux in patients with acute, symptomatic superficial vein thrombosis of the legs?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
64.0% female
36.0% male
N = 3002
3002 patients (1918 female, 1084 male).
Inclusion criteria: patients with acute, symptomatic lower limb superficial vein thrombosis at least 5 cm long, as confirmed by standardized compression ultrasonography.
Key exclusion criteria: cancer treatment within the previous 6 months; symptomatic or asymptomatic DVT, symptomatic documented PE, or documented history of superficial vein thrombosis within the previous 3 months or DVT or PE within the previous 6 months.
Interventions
N=1502 fondaparinux (subcutaneous dose of 2.5 mg daily for 45 days).
N=1500 placebo (matching placebo of sodium chloride SC once daily for 45 days).
Primary outcome
Death from any cause or symptomatic pulmonary embolism, symptomatic deep vein thrombosis, or symptomatic extension to saphenofemoral junction or symptomatic recurrence of superficial vein thrombosis at day 47
0.9%
5.9%
5.9 %
4.4 %
3.0 %
1.5 %
0.0 %
Fondaparinux
Placebo
Significant
decrease ▼
NNT = 20
Significant decrease in death from any cause or symptomatic PE, symptomatic DVT, or symptomatic extension to the saphenofemoral junction or symptomatic recurrence of superficial vein thrombosis at day 47 (0.9% vs. 5.9%; RR 0.15, 95% CI 0.08 to 0.26).
Secondary outcomes
Significant decrease in DVT or PE at 47 days (0.2% vs. 1.3%; RR 0.15, 95% CI 0.05 to 0.5).
No significant difference in death at 47 days (0.1% vs. 0.1%; RR 1.99, 99% CI 0.18 to 21.87).
Safety outcomes
No significant differences in major bleeding (0.1% vs. 0.1%, p=1.00).
Significant difference in serious adverse events (0.7% vs. 1.1%).
Conclusion
In patients with acute, symptomatic lower limb superficial vein thrombosis at least 5 cm long, as confirmed by standardized compression ultrasonography, fondaparinux was superior to placebo with respect to death from any cause or symptomatic PE, symptomatic DVT, or symptomatic extension to the saphenofemoral junction or symptomatic recurrence of superficial vein thrombosis at day 47.
Reference
Decousus H, Prandoni P, Mismetti P et al. Fondaparinux for the treatment of superficial-vein thrombosis in the legs. N Engl J Med. 2010 Sep 23;363(13):1222-32.
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