Background: Up to 50% of men with poor prognosis non-seminoma GCT die with standard BEP chemotherapy. An intensive regimen, CBOP/BEP (carboplatin, bleomycin, vincristine, cisplatin/BEP), met response targets in a phase II, multicentre, open-label, randomized trial (74% with complete response or partial response marker negative, 90% CI 61% to 85%; primary outcome). Here, we report long term outcomes and prognostic factors. Methods: Patients with extracranial GCT and IGCCCG poor prognosis features were randomised to 4xBEP or CBOP/BEP (2xCBOP, 2xBO, 3xBEP with bleomycin dose 15,000iu). Low-dose, stabilising chemotherapy prior to entry was permitted. This analysis focuses on progression-free survival (PFS), overall survival (OS) and toxicity (all secondary outcomes), and exploratory analysis of prognostic factors and the impact of marker decline (as defined in GETUG13). Results: 89 patients (43 CBOP/BEP) were randomised. After median 63 months follow-up, 3-year PFS is 55.7% (95% CI 39.7%, 69.0%) for CBOP/BEP arm, 38.7% (24.7%, 52.4%) for BEP (HR 0.59 (0.33, 1.06), p = 0.079). 3-year OS is 65.0% (48.8%, 77.2%) and 58.5% (43.0%, 71.2%) respectively (HR 0.79 (0.41, 1.52), p = 0.49). 12-month toxicity was affected by subsequent treatments, with no clear differences between arms. There was no grade ≥3 toxicity in the CBOP/BEP arm. In multivariate models, use of pre-protocol chemotherapy was the only factor associated with poorer PFS (HR2.09 (1.14, 3.81), p = 0.017). Mediastinal primary (HR 2.13 (1.02, 4.46), p = 0.045) and use of pre-protocol chemotherapy (HR 3.40 (1.74, 6.63), p < 0.001) were associated with poorer OS. Unfavourable marker decline, in 60 (70%) patients, was not associated with other prognostic factors, nor with long term outcomes (HR 0.82 (0.44, 1.53), p = 0.54 for PFS). Conclusions: The trial was not powered to compare PFS and OS, but PFS results for CBOP/BEP are promising, and similar to the intensive arm of GETUG13. Impact on OS was less clear (and will be affected by subsequent therapy). Use of pre-protocol chemotherapy was associated with poorer outcomes. Further study in an international phase III trial is warranted. Clinical trial identification: ISRCTN53643604. Legal entity responsible for the study: Medical Research Council, UK. Funding: Cancer Research UK (grant no CRUK/05/014). Disclosure: R.A. Huddart: Stock or other ownership interests: Cancer Centre London LLP; Consulting or advisory role: MSD, Roche, Bristol-Myers Squibb; Speaker’s bureau: Roche, Elekta; Research funding: MSD, Elekta; Travel expenses: Roche, MSD. All other authors have declared no conflicts of interest.