Proteinase 3 PR1 Peptide Mixed With Montanide ISA-51 VG Adjuvant and Administered With GM-CSF and PEG-INTRON(R)

Inclusion Criteria:

1. Patients \>/= 18 years with Philadelphia chromosome (Ph)- or BCR/ABLpositive CML (as determined by cytogenetics, FISH, or PCR).
2. Patients must have received imatinib therapy for at least 18 months and not have increased their dose of imatinib in the last 6 months.
3. Patients must be in complete cytogenetic remission.
4. Patients must have detectable BCR-ABL transcript levels meeting at least one of the following criteria: 1) Patient has never achieved a major molecular response (i.e., never reached levels \<0.05%), and transcript levels have shown in at least two consecutive measures separated by at least 1 month to have increased by any value, or
5. continued from above: 2) Achieved a major molecular response that has been lost with an increase in transcript levels by at least 1-log over two consecutive analyses separated by at least 1 month, or 3) BCR-ABL transcript levels have reached a plateau defined as a ratio that is not more than 0.25-log (one fourth of a log) lower than the lowest value obtained in the last at least 6 months, with at least 2 values obtained during this period.
6. Patients must not have had a continuous interruption of imatinib therapy of greater than 14 days or any interruptions totaling 6 weeks within the 6 months prior to enrollment.
7. Patients must be HLA-A2 positive at one allele
8. Patients must give informed consent and sign an informed consent indicating that they are aware of the investigational nature of this study in keeping with the policies of the hospital.
9. Eastern Cooperative Oncology Group (ECOG) performance status \</= 2.
10. Adequate organ function defined as: bilirubin \<2 times upper limit of normal (ULN), creatinine \<1.5 times ULN, and serum glutamate pyruvate transaminase (sGPT) \<2.5 times ULN.
11. Women of childbearing potential should practice effective methods of contraception.

Exclusion Criteria:

1. Patients with a history or clinical evidence of autoimmune disorders
2. Patients receiving immunosuppressive therapy including cyclosporine, or FK506 within 3 months of study entry
3. Chronic use (\> 2 weeks) of greater than physiologic doses of corticosteroid agent (dose equivalent to \> 10 mg/day of prednisone) within 28 days of the first day of study drug treatment (topical and inhaled corticosteroids are permitted)
4. GM-CSF or interferon administration within 1 month of first PR1 injection
5. Patients receiving any other investigational agents currently or within the past 4 weeks. Patients must have recovered from any adverse effects of investigational therapy.
6. Patients who are pregnant or breast-feeding
7. Patients with clinically significant heart disease (New York Heart Association (NYHA) Class III or IV)
8. Patients with positive cANCA
9. History of HIV positivity or AIDS
10. Chloroma at time of study screening
11. Prior vaccine therapy for Chronic myelogenous leukemia (CML)
12. Known allergy to Montanide ISA-51 VG adjuvant