Bosentan in Digital Ulcers

Long-term Bosentan Open Label Extension of the AC-052-331 Study in Systemic Sclerosis Patients With Ischemic Digital Ulcers

The aim of the study is to collect long-term efficacy, tolerability and safety data of bosentan in Systemic Sclerosis (SSc) patients suffering from ischemic digital ulcers (DUs).

Inclusion Criteria:

1. Patients with SSc according to the classification criteria of the American College of Rheumatology
2. SSc patients with at least one DU at baseline qualifying as a CU (see definition section 3.2.2)
3. CU occurred < 3 months and > 1 week prior to randomization. The subset of patients with SSc felt to be at high risk for DUs will be identified in the screening period but will not be eligible for enrollment until a CU has developed
4. Male or female patients >/= 18 years of age
5. Women of childbearing potential must have a negative pre-treatment pregnancy test and use a reliable method of contraception during study treatment and for at least 3 months after study treatment termination
6. Women not of childbearing potential are defined as postmenopausal (i.e., amenorrhea for at least 1 year), or surgically or naturally sterile
7. Signed informed consent.

Exclusion Criteria:

1. DUs due to condition other than SSc
2. Severe PAH (WHO class III and IV)
3. Systolic blood pressure < 85 mmHg
4. Hemoglobin concentration < 75% of the lower limit of the normal range
5. AST and/or ALT values greater than 3 times the upper limit of normal
6. Moderate to severe hepatic impairment, i.e., Child-Pugh Class B or C
7. Severe malabsorption or any severe organ failure (e.g., lung, kidney) or any life-threatening condition
8. Pregnancy or breast-feeding
9. Previous treatment with bosentan
10. Treatment with any of the following: glibenclamide (glyburide), fluconazole, cyclosporine A, tacrolimus and any other calcineurin inhibitor 1 week prior to randomization
11. Local injection of botulinum toxin in an affected finger 1 month prior to randomization
12. Treatment with parenteral prostanoids (prostaglandin E, epoprostenol, treprostinil sodium or other prostacyclin analogs) 3 months prior to randomization
13. Treatment with inhaled or oral prostanoids one month prior to randomization
14. Systemic antibiotics to treat infection of DUs 2 weeks prior to randomization
15. Treatment with phosphodiesterase inhibitors such as sildenafil, except for intermittent treatment of male erectile dysfunction
16. Body weight < 40 kg
17. Patient with conditions that prevent compliance with the protocol or adhering to therapy
18. Patient who received an investigational product within 1 month preceding screening
19. Known hypersensitivity to bosentan or any of the excipients.