5011 Background: A prior phase III trial (TARGETs) demonstrated that sorafenib (SOR) doubled median progression-free survival versus placebo in previously treated clear cell renal cell cancer (RCC) patients (pts). The ARCCS trial made SOR available to a broader range of RCC pts through an expanded access program. Methods: This open-label, nonrandomized trial enrolled pts with advanced RCC not eligible for, or without access to, other SOR clinical trials; ECOG PS 0–2 with waivers granted for pts with ECOG PS 3–4; age =15 yrs; and adequate prior treatment of brain metastases. Major exclusion criteria included treatment <4 wks prior, life expectancy <2 mos, uncontrolled hypertension, and severe renal impairment requiring dialysis. Objectives were to analyze the safety and efficacy (response by RECIST) of 400 mg bid SOR in a community-based setting. Enrollment ceased on 12/20/05 when SOR became commercially available in the US, and those with no prior therapy or non-clear cell RCC continued in an extension protocol. Enrollment completed in Canada in 8/06. Results: A total of 2488 pts were valid for safety: 69% male with median age 63 yrs and most (83%) had prior nephrectomy; histologies included 78% clear-cell, 7% papillary, 1% chromophobe, and <1% collecting duct and oncocytoma. Median time from diagnosis for all pts was 1.4 yrs (range <1–34). Of those pts receiving prior therapy (n=1249), treatments included interferon alfa (54%), interleukin 2 (43%), bevacizumab (23%), thalidomide (12%), and sunitinib (2%). Grade 3 and 4 adverse events occurring in > 2% pts were hand- foot skin reaction 7.2%, fatigue 5.3%, hypertension 4.4%, rash/desquamation 4%, dehydration and dyspnea 2.7%, and diarrhea 2.5%. Efficacy assessment, mainly PFS, was limited by the short median time (14 wks) on study due to many pts enrolling during the last 2 months of the study. Of 1,850 pts evaluable for response, 17.5% had unconfirmed PR. One (0.1%), 67 (3.6%), 1479 (79.9%) and 303 (16.4%) had CR, PR, SD, and PD, respectively. Conclusions: ARCCS pts were representative of the broader range of RCC pts in the community including those excluded from previous SOR trials. Toxicity and response rates were similar to those reported previously, supporting the generalizability of the phase III trial data. [Table: see text]