2-chlorodeoxyadenosine (2-CdA), a purine analog, has become universally accepted as the agent of choice in treating hairy cell leukemia (HCL). However, few studies have reported long-term outcomes after 2-CdA treatment. Between January 1990 and June 2003, 86 consecutive patients with HCL were treated with a single 7-day course of 2-CdA by continuous infusion at a dose of 0.1 mg/kg per day. Of the 86 patients (mean age: 49 years), 67 patients (79%) achieved a complete remission (CR); 18 patients (21%) achieved a partial remission (PR); and 1 patient's response was unable to be assessed. The progression-free survival (PFS) for initial relapse after 12 years was 54%. At a median follow-up of 9.7 years (range, 0.3-13.8 years), 31 (36%) of 85 patients relapsed. There were 23 relapsed patients treated with a second cycle of 2-CdA; 2 patients were treated with alternative agents; and 6 patients were observed. Of the 23 relapsed patients retreated with 2-CdA, 12 (52%) achieved a CR and 7 (30%) patients achieved a PR (overall response rate: 83%). The overall survival (OS) rate after 12 years was 87%. There were 15 patients (17%) who developed other malignancies. Long-term follow-up of up to 14 years (median: 9.7 years) showed an excellent PFS and OS for HCL patients after 2-CdA treatment.

537 Background: Treatment for locally advanced rectal cancer (LARC) includes preoperative radiation concurrent with fluoropyrimidine chemotherapy (CRT). Local recurrence is a problem. Cetuximab is active in colorectal cancer and is effective with radiotherapy in other diseases. This study evaluated the pathologic response rate for LARC treated with preoperative chemoradiotherapy w/wo cetuximab. Methods: LARC (T3/4 or LN+, M0) pts were randomized to Arm1/Arm2. Arm 1 received standard pelvic radiotherapy (5040-5400cGy in daily fractions) with continuous infusional 5-FU (225mg/m2/day); Arm 2 received identical chemoradiotherapy + concurrent cetuximab (400mg/m2 initial dose) 1 week before pelvic radiotherapy, followed by 250mg/m2 weekly for the duration of chemoradiotherapy. After study treatment completion, pts were re-evaluated clinically and radiographically for clinical response. After 6-8 weeks, patients underwent surgical resection. The primary end point was pathologic CR (pCR), and secondary endpoints included ORR, RFS, OS, and local recurrence rates. Results: 139 pts were enrolled (Arm 1=69/Arm2=70); Arm1/Arm2 median age 61/55 yrs, and stage II and III 59%, 39%/40%, 60%. In 124 postsurgery pts, pCR occurred in 17 Arm 1 pts (28.3%, 95% CI 17.5-41.4) and 17 Arm 2 pts (26.6%, 95% CI 16.3-39.1); TRG postsurgery was similar between treatment arms (Table). Grade 3 and 4 toxicities were largely nonhematologic: diarrhea 16%/22%, rash 0%/12%, dehydration 5%/8%, mucositis 5%/6%. The 5-yr RFS for Arm1/Arm2 was 61%/65%, 5-yr OS was 66%/83%, local recurrence was 3%/4%. Conclusions: The addition of cetuximab to preoperative CRT for LARC was associated with increased but manageable toxicities. pCR rates were similar between treatment arms, as were survival statistics and local recurrence rates. No association was found between KRAS status and pCR. Clinical trial information: NCT00527111. [Table: see text]