An extension study to QTI571A2301 to evaluate the longterm safety, tolerability and efficacy of oral QTI571 (imatinib) in the treatment of severe pulmonary arterial hypertension.

This study is designed to determine the long term safety, tolerability and
efficacy and tolerability of QTI571 in the treatment of PAH in patients who
have completed or discontinued the IMPRES study. Safety will be monitored by
standard safety laboratories, ECG, echocardiogram, adverse event reporting.
Measurement of weight and physical assessment will be used to monitor
peripheral edema and detrimental fluid retention.
Efficacy will be monitored by 6MWT and TTCW.
Echocardiograms will monitor right and left ventricular function and ECG will
monitor for any arrhythmias and conduction defects. These tests will determine
any long term cardiac toxicity related to QTI571.

Primary: To evaluate the long-term safety and tolerability of QTI571.
Secondary:
* Continue to evaluate the long-term efficacy of QTI571 as measured by the
change in
6MWD from baseline.
* Continue to assess time to clinical worsening (TTCW) endpoints including all
cause
mortality, hospitalization for worsening PAH for at least overnight
(established by
external adjudication committee), worsening of WHO functional class, or a drop
in
6MWD by 15% both as a composite endpoint and by individual time to clinical
worsening events.
* To assess the impact of QTI571 on medical resource utilization.

This is a multinational, multi center extension study in patients with PAH.
Informed Consent should be obtained at Visit 1 for all patients. Upon providing
written informed consent, patients will be screened for participation in the
extension study.
The following screening procedures must be performed within 2 weeks of
extension study enrollment (first drug assignment):
* Screening safety laboratories, ECG and 6MWD will be performed at Visit 1 if
not
performed in the previous 4 weeks.
* Echocardiogram will be performed at Visit 1 if not performed in the previous
8 weeks.
Patients may remain in the extension study at the maximum tolerated dose for up
to three years. At this timepoint, further access to QTI571 will be reviewed
and be dependent upon the outcome of the core Phase III study CQTI571A2301.

Treatment with QTI571.

Risk: Adverse effects of study medication.
Burden: 12 visits in over 2 years. Blood tests (approx. 10 ml/visit, aprox. 120
ml in total) and ECG during every visit.
In addition: Phys. examination 5x, echocardiogram 33-4x, 6 minute walk test
5-6x, pregnancy test 4-5x.
Extra in comparison to regular treatment : more and longer lasting visits, more
often blood tests, extra ECG and echocardiogram (differnces depending on the
physical condition of the individual patient), 6 minute walk test 5-6x (for
study purposes only).