4533 Background: E1201 included operable esophageal adenocarcinoma, staged II-IVa by EUS. Endpoints were pathologic complete response (pCR), toxicity, and tolerability of these two experimental regimens. pCR was used as a surrogate endpoint. As previously reported, the pCr rates indicated that these regimens did not meet criteria for further study based on a target of 45% against the null hypothesis of 25% for standard therapy. This report contains details of toxicity, tolerability of adjuvant chemotherapy, and prognostic value of EUS staging. Materials/Methods: 90 eligible pts enrolled. Arm A was Cisplatin (C) 30mg/m2 and Irinotecan (I) 50 mg/m2 on days (d) 1,8,22,29 of 45 Gy RT/5 weeks. Post-op therapy was C 30 mg/m2 and I 65 mg/m2 d 1, 8 q21 days x 3. Arm B therapy was C 30 mg/m2 and Paclitaxel (P) 50 mg/m2 1 hour infusion d 1,8,15, 22, 29 with RT. Postoperative therapy was C 75 mg/m2 and P 175 mg/m2 day 1 q21 days x 3. Results: Of all eligible patients, 83% (38/46) and 70% (31/44) had a complete resection with negative margins and 6/46 (15%) (95% CI = 5%, 26%) and 7/44 (16%) (95% CI = 7%, 30%) had pCR on arm A and B respectively. Confirmed EUS staging was available for 71 pts, Path CR rate was 3/19(16%) for stage T2- 3N0M0 and 7/52(14%) for stages T1–3N1M0 or T1–3N0- 1M1a. The incidence of ≥ grade 3 hematology toxicity, dysphagia, and diarrhea during neoadjuvant therapy were 20 (43%), 6 (13%), 4 (9%) for arm A (nTOX=47) and 18 (39%), 9 (20%), and 1 (23%) for arm B (nTOX=46). Zero, one, two and three cycles of adjuvant chemotherapy were received by 26%, 20 %, 5% and 49% of operated patients in arm A (n=41) and 36%, 14%, 3%, and 47% in arm B (n=36). Two of 77 (3%) operated patients died within 30 days of surgery. Conclusions: The low pCR rates suggest that neither regimen is likely to advance treatment of esophageal/GEJ adenoca over preoperative cisplatin/5-FU/RT and therefore do not warrent pursuing. EUS stage did not appear to influence response rate with these regimens. Moreover, these regimens are associated with significant toxicity and, as with other regimens, only a minority of patients were able to receive the planned adjuvant therapy. Survival follow-up continues. No significant financial relationships to disclose.