e16031 Background: Patients with relapsed metastatic GCT following treatment with cisplatin based combination chemotherapy, may be cured with further intensive chemotherapy. A Medical Research Council trial of TIP achieved 1 year progression free survival (PFS) of 38% with 65% survival (Br J Cancer. 2005;93:178). A more dose intense schedule of TIP with growth factors achieved 2-year PFS of 91% (Proc Am Soc Clin Oncol. 22:2003 [abstr 1537]). Gemcitabine has activity in the treatment of multiply relapsed disease. This study aims to investigate the feasibility of adding gem to TIP with the addition of growth factor support, while maintaining TIP dose intensity, with a view to improving the outcome from TIP alone. Methods: A phase I dose escalation study of Gem-TIP was carried out in patients at first relapse from metastatic GCT following cisplatin chemotherapy. All patients received TIP without dose reduction (paclitaxel 175 mg/m2 d1, cisplatin 20 mg/m2 d1–5, ifosphamide 1 g/m2 d2–6) with GCSF days 7–18 of a 21 day cycle for maximum 4 cycles. 3 dose levels of gem were investigated, 600 mg/m2 d1, 900 mg/m2 d1 and 1,200 mg/m2 d1. Dose limiting toxicity (DLT) was non-haematological grade 3 or 4, except nausea, vomiting and alopecia. Results: 13 patients treated, 12 male, 1 female, age 21–48 years. Baseline histology seminoma 8, non-seminoma 5. Cohort 1: 4 patients treated, 1 withdrew after 1 cycle. No DLT observed. Cohort 2: 3 patients completed treatment with no DLT. Cohort 3: 1 patient treated suffered allergic pneumonitis at cycle 1 complicated by a malignant pleural effusion. A further 5 patients were treated at this dose level. The minimum course duration was 63 days. The mean duration for each cohort was 69 days for cohort 1 and 2, 64 days for cohort 3. Grade 3/4 haematological toxicity was; neutropaenia 9 patients, thrombocytopaenia 10 patients, with 2 episodes of febrile neutropaenia but no bleeding. 10 platelet transfusions were required. 10 patients were assessable for response, 5 CR, 3 PR, 2 PD. At median follow up 18 months the median PFS is 10 months. Conclusions: Gem-TIP can be delivered with 1200mg/m2 gem with manageable toxicity in the context of growth factor support. This dose will be taken forward to a phase II study. No significant financial relationships to disclose.