Phase II Study of NRX 195183 Therapy for Patients With Relapsed or Refractory Acute Promyelocytic Leukemia

Inclusion Criteria:

- Clinical diagnosis of APL morphology or FAB M3 variant confirmed by RT-PCR assay or
chromosome analysis/FISH showing t(15:17) translocation. Patients must also have
relapse from, resistance to or intolerance of any one or more of the following
therapies:

- ATRA

- Cytotoxic chemotherapy

- Arsenic trioxide

- Patients must be 18 or older.

- Bilirubin equal or less than 1.5 times the upper limit of normal.

- Creatinine equal or less than 1.5 times the upper limit of normal.

- Patients entered into this study should be non-pregnant and non-nursing and should
not plan on becoming pregnant while on treatment. Treatment under this protocol
would expose an unborn child to significant risks. Women and men of reproductive
potential should agree to use an effective means of birth control. There is an
extremely high risk that a severely deformed infant will result if NRX 195183 is
administered during pregnancy.

Exclusion Criteria:

- Non-APL, AML patients should be excluded from the study.

- Other serious illnesses which would limit survival to 6 months.

- Psychiatric conditions which would prevent compliance with treatment or informed
consent.

- Uncontrolled or severe cardiovascular disease. This would include history of a
recent acute myocardial infarction, uncontrolled congestive heart failure, or active
angina.

- AIDS or HIV positive patients, although HIV test is not required for accrual.