A phase I/II study of capecitabine (Cape), oxaliplatin (Ox), panitumumab (Pmab), and external beam radiation therapy (RT) for patients with esophagogastric carcinoma (EC).

68 Background: EC is commonly managed with concurrent chemoradiotherapy, with or without surgical resection. The optimal combination and dose of agents is the subject of continued investigation. This study examines chemotherapeutic agents with known efficacy in EC in combination with the EGFR inhibitor panitumumab. METHODS: Eligible pts received RT (1.8 Gy qd to 50.4 Gy) combined with concurrent chemotherapy. Dose-level (DL) 1 was cape (625 mg/m2/bid RT days), ox (40 mg/m2 weekly X 6 weeks), and pmab (3.6 mg/kg, weeks 1, 3 and 5). Chemotherapy doses were escalated barring dose limiting toxicity (DLT). The primary endpoint was defining the maximally tolerated dose with this combination. Secondary endpoints included toxicity and radiographic/pathologic response rates. RESULTS: Twenty-nine pts were enrolled. Twenty-five had adenocarcinoma, 24 (83%) were cN+ and 9 (31%) had M1a/b disease. DLT was not encountered in DL 1. Two of 6 patients at DL 2 (cape 825 mg/m2/bid RT days, ox 50 mg/m2 weekly, pmab 4.8 mg/kg, weeks 1, 3 and 5) developed DLT (one hospitalization due to dehydration; one with drug reaction requiring hospitalization). Twenty additional pts were enrolled at DL1. Primary toxicities were EGFR-rash, esophagitis, nausea/vomiting and fatigue. On repeat endoscopy, 16 (55%) had CR, 10 (35%) PR and 2 (7%) SD. Using PERCIST criteria, 12 (41%), 11 (38%), 2 (7%) and 3 (10%) had CR, PR, SD and PD response on restaging PET, respectively. Twenty pts underwent esophagectomy, revealing Gr 0 response (no residual disease) in 9 (45%), Gr 1 (single/microscopic cells) in 3 (15%), Gr 2 (fibrosis > gross disease) in 4 (20%) and Gr 3 (gross residual > fibrosis or no evident response) in 4 (20%). Seven pts (35%) experienced anastomotic leak (2 requiring reoperation and 3 stent placement). CONCLUSIONS: Concurrent chemoradiotherapy utilizing capecitabine, oxaliplatin, panitumumab is reasonably well-tolerated and associated with high rates of radiographic, endoscopic and pathologic response. Postoperative anastomotic leak rates were higher than expected. Further study of this regimen in the operative and nonoperative settings is warranted.

Duke Scholars

Author Brian Gary Czito Radiation Oncology

Author Manisha Palta Radiation Oncology

Author Shannon Jones McCall Pathology