Background

The most common malignancy affecting adolescent and young adult males in Western countries is germ cell tumours (GCTs) [1]. Although most patients with good prognostic features have excellent outcomes, the cure rates for male patients with advanced disease and intermediate or poor prognostic features are only 79 and 48% respectively [2]. GCTs are rarer in females, however in females aged between 10 and 30 years they account for 70% of ovarian neoplasms [3].

The efficacy of first-line chemotherapy has not improved since the introduction of bleomycin, etoposide, cisplatin (BEP) in the mid-1980s. BEP chemotherapy given every 3 weeks for 4 cycles remain the global accepted standard of care for intermediate, and poor prognosis male patients [4]. Paediatric and female patients with GCTs are often not included in clinical trials due to the rarity of disease. The current management algorithms for these groups are based on extrapolations from other settings [3, 5].

Accelerating chemotherapy by administering the same doses more frequently has increased cure rates in other cancers, including breast cancer, lymphoma (prior to rituximab) and Ewing’s sarcoma [6,7,8]. The hypothesised mechanism is that accelerated chemotherapy with shorter cycles can overcome the rapid regrowth of shrinking tumours induced by chemotherapy [9, 10]. Accelerating chemotherapy is feasible with the development and availability of therapeutic granulocyte colony–stimulating factor (G-CSF) e.g. filgrastim, which reduces the duration of leukopenia [11]. Accelerated regimens may be preferable to patients as treatment is completed faster, it may improve compliance and has minimal additional financial cost.

A single arm phase 2 trial of 43 patients demonstrated that the regimen is feasible and tolerable [12]. The long term efficacy data appears promising with 5 year overall survival of 92% (95% CI 54% to 99%) for patients with poor prognostic features and 94% (95% CI 63% to 99%) for patients with intermediate prognostic features [13].

The aim of this phase 3 trial is to determine if accelerated BEP is superior to standard BEP as first-line chemotherapy for intermediate and poor-risk metastatic GCTs.

Methods

Study design

This trial is an open label randomised, 2-arm, multi-centre, phase 3 trial. Participants are randomised 1:1 to receive 4 cycles of either accelerated BEP chemotherapy given 2 weekly or standard BEP chemotherapy given 3 weekly (Fig. 1). Randomisation will be implemented using a minimisation approach balancing for; ECOG performance status (0–1 vs 2–3), International germ cell cancer consensus classification (IGCCC) risk group (intermediate vs poor), primary site (mediastinal vs other), brain metastases (present vs absent), induction chemotherapy (present vs absent), age (≥ 16 years vs < 16 years), gender (male vs female), and study site.

Fig. 1
figure 1

Study Schema

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This international trial is led by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) in collaboration with the National Health and Medical Research Council Clinical Trials Centre (NHMRC CTC), Sydney, Australia. Key international collaborators include the Cambridge Clinical Trials Unit (United Kingdom), Children’s Oncology Group (United States) and Cancer Trials Ireland. Forty eight participants have been recruited from Australia and New Zealand since 2014, and 4 from the United Kingdom since opening to recruitment in 2017. The Children’s Oncology Group and Cancer Trials Ireland are planned to open to recruitment in the near future. The study will be performed in accordance with the Declaration of Helsinki and satisfy the regulatory requirements in Australia, United Kingdom and United States of America.

Study objectives

The primary objective is progression-free survival (PFS), defined as from the date of randomisation until the criteria for disease progression are met or death. Secondary objectives include response following treatment completion (protocol specific criteria), adverse events (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 [14]), health related quality of life (QLQ-C30 [15] and -TC-26 [16]), treatment preference, delivered dose-intensity of chemotherapy and overall survival. Tertiary objectives include exploratory studies of biomarkers and their correlations with clinical outcome. Initial response assessment is measured at the 30–42 day safety assessment. Final response assessment at 6 months from randomisation or after all post-chemotherapy surgery and other interventions are completed. Participants will continue regular follow-up for at least 5 years.

Eligibility criteria

Key inclusion and exclusion criteria include age between 11 and 45 years, intermediate or poor prognosis germ cell tumour as defined by IGCCC (modified with different lactate dehydrogenase criteria for intermediate risk non-seminoma, and inclusion of ovarian primaries) and adequate organ function. Participants who need to start therapy urgently may commence study chemotherapy prior to registration and randomisation given the treatment is identical for the first 2 weeks and forms part of standard of care management. Such participants must be discussed with the coordinating centre prior to subsequent registration, and they must then be registered within 10 days of commencing chemotherapy. The full eligibility criteria are listed in Table 1.

Table 1 Eligibility Criteria
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Treatment

The experimental arm is accelerated BEP given as bleomycin 30,000 international units (IU) (15,000 IU/m2 in participants aged less than 16) intravenous (IV) weekly on day 1 and 8, etoposide 100 mg/m2 on days 1–5 and cisplatin 20 mg/m2 on days 1–5 every 2 weeks for 4 cycles, followed by single agent bleomycin 30,000 IU (15,000 IU/m2 in participants aged less than 16 years) IV once a week for a further 4 weeks to a total of 12 doses of bleomycin. The control arm is standard BEP given as bleomycin 30,000 IU (15,000 IU/m2 in participants aged less than 16) IV weekly on day 1, 8 and 15, etoposide 100 mg/m2 on days 1–5 and cisplatin 20 mg/m2 on days 1–5 every 3 weeks for 4 cycles. G-CSF support is given in both treatment arms.

Every attempt should be made to deliver chemotherapy at full dose and without delay from the planned schedule, as dose and dose-intensity are important predictors of outcome. Dose reductions for etoposide are specified in the protocol. There are no dose reductions for cisplatin or bleomycin allowed. Study treatment will be permanently discontinued for unacceptable toxicity, delay of day 1 of treatment for more than 21 days due to treatment-related adverse events, unequivocal progression, occurrence of an exclusion criteria or illness affecting participant safety, failure to comply with the protocol or if the investigator does not think it is in the participant’s best interest to continue. If a participant develops pulmonary toxicity then bleomycin should be stopped. If the participant has poor risk disease and less than 8 doses of bleomycin have been administered then the participant should stop BEP, and ifosfamide and mesna should be used with cisplatin and etoposide, as per the etoposide, ifosfamide, cisplatin (VIP) regimen. Surgical resection of residual masses and subsequent treatment following the completion of chemotherapy are specified in the protocol.

Assessment schedule

Participants are assessed at baseline, prior to each cycle of chemotherapy, at completion of study treatment, then at 6, 9, 12, 18, 24, 30, 36, 42, 48, 54 and 60 months from randomisation (Table 2). Assessments at each time point include performance status, adverse events, blood tests (blood count, biochemistry, tumour markers), quality of life (up to 12 months), lung function tests (for Australian sites up to 12 months), CT imaging (at baseline; after randomisation at 4, 12, 24 and 60 months; and as clinically indicated), disease status, subsequent treatment and survival. Biospecimens including tumour tissue (formalin-fixed paraffin-embedded) and blood (whole blood and plasma) at baseline will be collected from consenting participants for use in future translational research.

Table 2 Schedule of Assessments
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Statistical analysis

Stage 1 of the study will recruit 150 participants (75 per arm) which will provide 80% power at the 5% level of significance to detect an improvement in the favourable response rate from 59% with standard BEP to 80% with accelerated BEP. If results from Stage I are promising, Stage 2 of the study will recruit an additional 350 participants for a total sample size of 500 participants. A study of 500 patients followed until 140 PFS events are observed will provide > 80% power at the 5% level of significance to detect a hazard ratio of 0.6. An effect of this size corresponds to a 7% improvement in PFS at 2 years from 81% with standard BEP to 88% with accelerated BEP.

Discussion

The results of this study will determine if accelerated BEP chemotherapy is superior to standard BEP chemotherapy in the first-line treatment of intermediate and poor-risk metastatic GCTs. The collection of biospecimens will allow for future translational research studies to determine associations between biomarkers (to be specified) and their correlations with clinical outcomes. This is the first international randomised clinical trial for intermediate and poor-risk metastatic extra-cranial GCTs involving both adult and pediatric age groups open to both males and females.