8544 Background: The GHSG HD9 trial had established BEACOPP escalated (BE) as new standard of care for advanced-stage HL patients. The successor study, HD12, evaluated a possible reduction in toxicity by comparing 8 cycles of BE with 4 cycles BE followed by 4 cycles BB. The second question in this trial related to the need of additional radiotherapy (RT) to initial bulk and residual disease. Methods: HL patients in stage IIB with large mediastinal mass and/or E-lesions or stage III/IV were randomised according to a 2x2-factorial design between: 8BE + RT, 8BE no RT, 4BE+4BB + RT, 4BE+4BB no RT. Primary endpoint of the trial was FFTF. Between 9/1999 and 1/2003, a total of 1,670 patients aged 16–65 were randomized. For this final analysis at a median follow up of 78 months, 99 patients were excluded for various reasons resulting in 1,571 eligible patients. Results: Patient characteristics in the 4 groups were comparable. Treatment-related toxicity of WHO grade III/IV was observed in 97% of patients. Most prominent differences between pooled chemotherapy arms were anemia (65% 8BE vs 51% 4BE+4BB) and thrombopenia (65% vs 51%). Treatment outcome: complete remission 92.4%; early progression 2.2%; progression/relapse 7.8% (6.6% and 8.5%). A total of 156 (9.9%) deaths (72 vs 84) have been observed (22 vs 32 acute or salvage treatment toxicity; 15 vs 24 HL; 22 vs 13 secondary neoplasia). Most treatment related deaths occurred in the >60 years age group, the first 4 cycles and the IPS> 3 RF groups. Secondary neoplasias were observed in 77 patients (4.9%). At 5 years, OS was 91%, FFTF 85.5% and progression free survival (PFS) 86.2% (Kaplan-Meier estimates). Estimates for the difference at 5 years are 1.8% for OS, 2.3% for FFTF and 2.7% for PFS favoring BE. However, there was no statistical difference between 8x BE and 4BE+4BB in all outcome parameters (p>0.19, log rank test). There is also no significant difference between the RT or no-RT arms in this study. Conclusions: The adoption of 4BE+4BB as a new standard in the future GHSG studies will depend on a refined analysis of the total data set and will be presented. No significant financial relationships to disclose.