Exploring a new strategy for metastatic germ cell tumours

Cure rates for patients with poor- and intermediate-risk metastatic germ cell tumours (GCTs) lag behind those for patients with good-risk metastatic GCTs. The Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) aims to improve these cure rates. The P3BEP trial aims to determine whether an accelerated chemotherapy regime is more effective than the existing standard protocol.

For patients with metastatic GCTs, cure rates are currently >90% in good-risk disease, 85% in intermediate-risk disease, and only 70% in poor-risk disease. These are the rates seen with current first-line therapy, which consists of four 3-weekly cycles of bleomycin, etoposide, and cisplatin (BEP) administered over a 12-week treatment period. ANZUP aims to determine whether shortening the treatment cycles in metastatic GCTs will yield the same superior cure rates achieved by shortening the treatment cycles in other cancers [1].

The safety and feasibility of an accelerated chemotherapy protocol in patients with intermediate- and poor-risk metastatic GCTs have already been confirmed in phase 1 and 2 trials. With these favourable results, Ms Shalini Subramaniam (NHMRC Clinical Trials Centre, University of Sydney, Australia) and colleagues have now devised an accelerated treatment protocol which administers BEP in four 2-weekly cycles, followed by 4 doses of bleomycin, administered once per week for 4 weeks for a total intervention of 12 weeks.

The randomised, open-label, phase 3 trial P3BEP (NCT02582697) aims to randomise 500 participants (males and females) aged 11–45 years who have poor- or intermediate-risk metastatic GCTs of the mediastinum, ovary, retroperitoneum, or testis to receive either the standard chemotherapy regime or the accelerated BEP regime as described above, over a period of 12 weeks. ANZUP pointed out that this is the first trial of its kind to include adults as well as children of both sexes.

The trial consists of 2 stages; the primary endpoint for stage 1 is complete response; stage 1 analysis is expected to occur mid 2021. An interim analysis has identified no safety concerns to date. The primary endpoint for stage 2 is progression-free survival at 2 years.

Several key secondary outcome measures are monitored: initial response after 12 weeks of treatment, final response at 6 months, adverse events, health-related quality of life, treatment preference, delivered dose-intensity of chemotherapy (relative to standard BEP), and overall survival rates.

The authors conclude that a positive result of this trial may change standards of care.

1. Subramaniam S. P3BEP (ANZUP 1302): An international randomized phase III trial of accelerated versus standard BEP chemotherapy for male and female adults and children with intermediate and poor-risk metastatic germ cell tumours (GCTs). Abstract TPS 390, ASCO Genitourinary Cancers Symposium, 11–13 February 2021.

 

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Posted on 24 March 202118 June 2021