A Phase II Study with Lead-In Safety Cohort of 5-Fluorouracil, Oxaliplatin, and Lapatinib in Combination with Radiation Therapy as Neoadjuvant Treatment for Patients with Localized HER2-Positive Esophagogastric Adenocarcinomas.

LESSONS LEARNED: Neoadjuvant 5-fluorouracil, oxaliplatin, and lapatinib in combination with radiation therapy is safe for neoadjuvant treatment for patients with localized human epidermal growth receptor 2-positive esophagogastric adenocarcinoma.Evaluation of this drug combination in a larger patient pool would allow for more accurate analysis of its efficacy. BACKGROUND: The optimal design of neoadjuvant chemoradiation for the treatment of localized esophagogastric cancers is the subject of much debate. In this nonrandomized trial, we evaluated neoadjuvant 5-fluorouracil (5-FU), oxaliplatin, and lapatinib in combination with radiation therapy as neoadjuvant treatment for patients with localized human epidermal growth receptor 2 (HER2)-positive esophagogastric adenocarcinomas. METHODS: Patients received neoadjuvant 5-FU (225 mg/m2 continuous intravenous infusion, days 1-42), oxaliplatin (85 mg/m2 intravenously [IV], days 1, 15, and 29), and lapatinib (six patients, 1,000 mg p.o., days 1-42; six patients, 750 mg p.o., days 1-42) plus radiation (1.8 Gy/day Monday through Friday for 50.4 Gy total). Following restaging, eligible patients underwent definitive resection, and pathologic response to neoadjuvant therapy was assessed. Planned enrollment was 42 patients. The primary endpoint was the pathologic complete response (pCR) rate. RESULTS: Twelve patients (median age 64 years; 67% male) received a median of 5.6 weeks of treatment (range: 1.1-8.4). The pCR rate was 8%; four of the 12 patients underwent tumor resection and one patient had a pCR, with pathologic partial response in the remaining three. The most common lapatinib-related adverse events included (all grades) nausea (67%) and diarrhea (58%), although these were all grade 1 or 2. Enrollment was halted due to low accrual. CONCLUSION: The treatment regimen was determined to be safe. The study was terminated early due to low accrual.

G-CSF signaling can differentiate promyelocytes expressing a defective retinoic acid receptor: evidence for divergent pathways regulating neutrophil differentiation.

Several lines of investigation suggest that granulocyte colony-stimulating factor (G-CSF) augments all-trans retinoic acid (ATRA)-induced neutrophil differentiation in acute promyelocytic leukemia (APL). We sought to characterize the relationship between G-CSF- and ATRA-mediated neutrophil differentiation. We established a G-CSF receptor-transduced promyelocytic cell line, EPRO-Gr, derived from the granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent EPRO cell line harboring a dominant-negative retinoic acid receptor alpha (RARalpha). In EPRO-Gr, neutrophil differentiation occurs either in GM-CSF upon addition of ATRA or upon induction with G-CSF alone. Transient transfection of EPRO-Gr cells with a RARE-containing reporter plasmid demonstrates increased activity in the presence of ATRA, but not G-CSF, while STAT3 phosphorylation occurs only in response to G-CSF. This suggests that ATRA-mediated differentiation of EPRO-Gr cells occurs via a RARE-dependent, STAT3-independent pathway, while G-CSF-mediated differentiation occurs via a RARE-independent, STAT3-dependent pathway. ATRA and G-CSF thus regulate differentiation by divergent pathways. We characterized these pathways in the APL cell line, NB4. ATRA induction of NB4 cells resulted in morphologic differentiation and up-regulation of C/EBPepsilon and G-CSFR, but not in STAT3 phosphorylation. The addition of G-CSF with ATRA during NB4 induction resulted in STAT3 phosphorylation but did not enhance differentiation. These results may elucidate how G-CSF and ATRA affect the differentiation of primary and ATRA-resistant APL cells.