Treatment of refractory germ-cell tumours with single-agent cabazitaxel: a German Testicular Cancer Study Group case series

Purpose Outcomes of multiply relapsed, refractory germ-cell tumour (GCT) patients remain poor with an overall survival (OS) of a few months only. Thus, new therapeutic advances are urgently needed. Cabazitaxel has shown preclinical activity in platinum-resistant GCT models. Here, we report the first clinical case series of cabazitaxel treatment for platinum-refractory GCT. Methods Data of multiply relapsed GCT patients receiving single-agent cabazitaxel were retrospectively analysed. Endpoints included 12-week progression-free survival (PFS) rate, disease control rate, tumour marker responses, median PFS and OS, and toxicity. Results Cabazitaxel showed limited activity in 13 heavily pre-treated GCT patients. After a median follow-up of 23 weeks (IQR 29), 69% of patients were deceased. A median of 2 cycles of cabazitaxel (range 1-7) were applied. The 12-week PFS rate was 31%. Median PFS and OS were 7 and 23 weeks, respectively. Two patients achieved objective responses (15%), three patients (23%) achieved a tumour marker decline >= 50%, and the disease control rate was 39%. Cabazitaxel was well tolerated. CTCAE degrees III-IV haemato-toxicity was most common (54%), and dose reductions were scarce (15%). Conclusion In this case series, cabazitaxel showed limited activity in heavily pre-treated GCT patients. Two-phase II studies are underway (NCT02115165, NCT02478502) prospectively assessing cabazitaxel in multiply relapsed GCTs.