5053 Background: Monocyte/macrophages (MO/MA) are an important population of innate immune effector cells. The goal was to develop an acceptable chemoimmunotherapy regimen for ovarian carcinoma (OC) patients based on mobilization and maturation of MO/MA. Methods: Eligibility: recurrent measurable tumors, chemo-free interval ≥ 6mos, ≤ 2 chemo regimens. Immunomodulatory regimen: GM-CSF (Leukine, Berlex) starting at 400 mcg/day SC for 7 days with IFNγ1b (Actimmune, Intermune) at 100mcg SC on days 5 and 7 administered prior to and 24 hours post chemotherapy (carboplatin Paraplatin AUC 5 IV) every cycle. Immune parameters: measured by FACS analysis of MO/MA, DC, and major subsets. MA mediated tumor cell (TC) cytotoxicity and ADCC against Her2neu+ TCs measured by 3-H thymidine incorporation. Quality of life (QOL): measured using the Functional Assessment of Cancer Therapy - General and Biologic Response Modifiers (FACT-G and FACT-BRM) at 3 time points in cycle one and at 2 time points in subsequent cycles. Results: Twenty-five patients, who completed ≥ 3 courses, were evaluated in this preliminary report. Six and 4 of 25 patients (40%) experienced CR and PR, respectively. Four patients were removed from the study due to severe carboplatin allergy (2 pts), grade 3 liver toxicity (1 pt), and grade 3 fatigue (1 pt). There were significant increases in mean absolute numbers of WBC, granulocytes, and MO from baseline to d+9 after carboplatin infusion for cycle #1 (p<0.001, p<0.001, and p=0.001, respectively). There was no change in the mean platelet levels through cycle #3 (p=0.13). The numbers of certain activated MO/MA subsets were also increased but without enhancement of direct cytotoxicity or ADCC. There was no effect on general QOL, though BRM specific symptoms were significantly suppressed (p=0.03). Conclusions: This novel regimen of GM-CSF, IFNγ, and carboplatin in OC patients has an acceptable toxicity profile, while significantly increasing absolute numbers of MO and granulocytes with a shift toward more differentiated cells. Further accrual will determine response rate, time to progression, and feasibility for future development and MO/MA functionality. No significant financial relationships to disclose.