Sargramostim in combination with irinotecan (I), 5-fluorouracil (F), and leucovorin (L) for metastatic colorectal cancer (CRC): Second interim results of PROGRESS trial

3663 Background: Weekly/biweekly irinotecan-based regimens improve survival in CRC patients but are associated with significant myelosuppressive toxicities. In the PROGRESS trial, sargramostim (Leukine®, GM-CSF) was added to two commonly used regimens to study its ability to reduce toxicities and allow increased chemotherapy dose delivery thereby delaying disease progression. Methods: Weekly: Day 1: 125 mg/m2 I, 500 mg/m2 F, 20 mg/m2 L. Sargramostim 250 μg/m2 on Days 2–6. Cycles consist of 4 weekly courses + 2 weeks rest for up to 48 weeks. Biweekly: Day 1: 180 mg/m2 I, 1000 mg/m2 F, 200 mg/m2 L. Day 2: 400 mg/m2 F bolus, followed by 600 mg/m2 F infusion over 22 hr; 200 mg/m2 L. Sargramostim 250 μg/m2 on Days 4–13 for up to 48 weeks. The primary endpoint is progression-free survival (PFS) at 24 weeks (using χ2 test and null hypothesis that PFS ≤ 55%). Results: Eighty-one patients were enrolled, and 64 were evaluable for PFS. Of these, 51 (80%) had liver involvement, 20 (31%) had lung involvement, and 24 (...