A Novel Single Arm Phase II Study for Relapsed Germ Cell Tumours With Poor Prognosis

Overview

The treatment of germ cell tumours is considered to be one of the major successes in the area of cytotoxic chemotherapy. Even in patients who relapse after first line therapy, a durable remission rate of between 25% and 60% has been seen using further chemotherapy. In 1999, researchers at St Bartholomew's Hospital developed the GAMEC protocol (combination chemotherapy with filgrastim, actinomycin D, methotrexate, etoposide, cisplatin). Results from this study showed that 50% of patients with relapsed testicular cancer could be cured using this treatment. When we reviewed the individual patients it was clear that older patients (\>35yrs) or patients with a raised Lactate Dehydrogenase (a blood test that monitors cancer activity), did not do as well. In addition, patients whose original tumour started in their chest (mediastinal germ cell tumour) have tended to do badly if they relapse. We have been developing a study for patients who fulfil at least one of these criteria. The GAMIO study (filgrastim, actinomycin D, methotrexate, irinotecan, oxaliplatin) has recently closed due to problems with high levels of toxicity from the irinotecan. GAMMA is a new study that will use paclitaxel instead of irinotecan and oxaliplatin instead of cisplatin. We expect that this treatment with oxaliplatin will be less damaging to the kidneys than cisplatin. Both oxaliplatin and paclitaxel and oxaliplatin and irinotecan have similar activity in relapsed patients in the phase II setting. We hope to improve on our previous results with this substitution and see if this will lead to an improvement in the cure rate of relapsed germ cell tumours with poor prognosis and reduce the side effects compared to our standard treatment. In addition, we do not expect any hearing damage and the treatment requires a shorter hospital stay.

Patients will receive a 4 drug combination chemotherapy in hospital over two nights. On the third day, the patient will receive an injection of pegfilgrastim. This stimulates the bone marrow to produce white blood cells and shortens the period of risk of serious infection. The treatment will be repeated every three weeks. This constitutes one cycle of treatment. We aim to give the patient four cycles of treatment over a total of twelve weeks. Before each cycle, the following will be conducted - physical examination, full blood count, urea + electrolytes, liver function tests, LDH, αFP, βHCG. Patients will have a FDG PET-CT scan at baseline, prior to cycle 2(approximately 1521 days after chemotherapy starts)and within 28 days of the last treatment, only if clinically indicated. On each cycle, serum creatinine should be measured 24 hours after the start of the methotrexate to exclude renal failure due to methotrexate. The following will be conducted at the end of treatment physical examination, full blood count, urea + electrolytes, liver function tests, LDH, αFP, βHCG. The patients will be monitored during chemotherapy and then monthly in the first year and two monthly in the second year. An interim analysis will be performed after 15 patients have completed treatment. If less than 9 responses are observed in this group, the study will be terminated. The final analysis will be performed after 43 patients have recruited, completed treatment and been followed for 24 months.