A Phase I/II Trial of Vaccination With Mutant Ras Peptide-Pulsed Dendritic Cells in the Treatment of HLA A2.1 Positive Patients With Colorectal Cancer

OBJECTIVES:

• Determine the frequency of immunologic response in patients with locally advanced or metastatic colorectal cancer treated with ras peptide-pulsed dendritic cell vaccine with or without interleukin-2.
• Determine the tumor response and survival time in patients with metastatic colorectal cancer treated with vaccine plus interleukin-2.
• Determine the time to progression in patients with locally advanced colorectal cancer treated with adjuvant vaccine.

OUTLINE: Patients are assigned to 1 of 2 treatment groups according to extent of disease. Patients with prior locally advanced disease are assigned to treatment group A, while those with metastatic disease are assigned to treatment group B.

• Group A: Patients are vaccinated against influenza on day -6. Patients undergo collection of peripheral blood mononuclear cells (PBMC) on day -4. The PBMC are cultured with sargramostim (GM-CSF) and interleukin-4 for 5 days and CD40 ligand for 24 hours and then pulsed for 2 hours with the appropriate peptide to form a vaccine. Patients receive ras peptide-pulsed dendritic cell vaccine IV over 5 minutes on days 1, 15, 29, 43, and 57.
• Group B: Patients undergo collection of PBMC and receive vaccination as in group A. Patients also receive interleukin-2 subcutaneously on days 2-6 and 9-13.

Treatment in both groups repeats every 2 weeks for up to 5 vaccinations in the absence of disease progression or unacceptable toxicity.