A.W.S. Ritchie

Survival with Newly Diagnosed Metastatic Prostate Cancer in the “Docetaxel Era”: Data from 917 Patients in the Control Arm of the STAMPEDE Trial (MRC PR08, CRUK/06/019)

BACKGROUND Prostate cancer (PCa) is the second most common disease among men worldwide. It is important to know survival outcomes and prognostic factors for this disease. Recruitment for the largest therapeutic randomised controlled trial in PCa--the Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy: A Multi-Stage Multi-Arm Randomised Controlled Trial (STAMPEDE)--includes men with newly diagnosed metastatic PCa who are commencing long-term androgen deprivation therapy (ADT); the control arm provides valuable data for a prospective cohort. OBJECTIVE Describe survival outcomes, along with current treatment standards and factors associated with prognosis, to inform future trial design in this patient group. DESIGN, SETTING, AND PARTICIPANTS STAMPEDE trial control arm comprising men newly diagnosed with M1 disease who were recruited between October 2005 and January 2014. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Overall survival (OS) and failure-free survival (FFS) were reported by primary disease characteristics using Kaplan-Meier methods. Hazard ratios and 95% confidence intervals (CIs) were derived from multivariate Cox models. RESULTS AND LIMITATIONS A cohort of 917 men with newly diagnosed M1 disease was recruited to the control arm in the specified interval. Median follow-up was 20 mo. Median age at randomisation was 66 yr (interquartile range [IQR]: 61-71), and median prostate-specific antigen level was 112 ng/ml (IQR: 34-373). Most men (n=574; 62%) had bone-only metastases, whereas 237 (26%) had both bone and soft tissue metastases; soft tissue metastasis was found mainly in distant lymph nodes. There were 238 deaths, 202 (85%) from PCa. Median FFS was 11 mo; 2-yr FFS was 29% (95% CI, 25-33). Median OS was 42 mo; 2-yr OS was 72% (95% CI, 68-76). Survival time was influenced by performance status, age, Gleason score, and metastases distribution. Median survival after FFS event was 22 mo. Trial eligibility criteria meant men were younger and fitter than general PCa population. CONCLUSIONS Survival remains disappointing in men presenting with M1 disease who are started on only long-term ADT, despite active treatments being available at first failure of ADT. Importantly, men with M1 disease now spend the majority of their remaining life in a state of castration-resistant relapse. PATIENT SUMMARY Results from this control arm cohort found survival is relatively short and highly influenced by patient age, fitness, and where prostate cancer has spread in the body.

Combining Enzalutamide with Abiraterone, Prednisone, and Androgen Deprivation Therapy in the STAMPEDE Trial

There are compelling reasons to study the addition of both enzalutamide and abiraterone, in combination, to standard-of-care for hormone-naïve prostate cancer. Through a protocol amendment, this will be assessed in the STAMPEDE trial, with overall survival as primary outcome measure.

Adding abiraterone or docetaxel to long-term hormone therapy for prostate cancer: directly randomised data from the STAMPEDE multi-arm, multi-stage platform protocol

Abstract Background Adding abiraterone acetate with prednisolone (AAP) or docetaxel with prednisolone (DocP) to standard-of-care (SOC) each improved survival in systemic therapy for advanced or metastatic prostate cancer: evaluation of drug efficacy: a multi-arm multi-stage platform randomised controlled protocol recruiting patients with high-risk locally advanced or metastatic PCa starting long-term androgen deprivation therapy (ADT). The protocol provides the only direct, randomised comparative data of SOC + AAP versus SOC + DocP. Method Recruitment to SOC + DocP and SOC + AAP overlapped November 2011 to March 2013. SOC was long-term ADT or, for most non-metastatic cases, ADT for ≥2 years and RT to the primary tumour. Stratified randomisation allocated pts 2 : 1 : 2 to SOC; SOC + docetaxel 75 mg/m2 3-weekly×6 + prednisolone 10 mg daily; or SOC + abiraterone acetate 1000 mg + prednisolone 5 mg daily. AAP duration depended on stage and intent to give radical RT. The primary outcome measure was death from any cause. Analyses used Cox proportional hazards and flexible parametric models, adjusted for stratification factors. This was not a formally powered comparison. A hazard ratio (HR) <1 favours SOC + AAP, and HR > 1 favours SOC + DocP. Results A total of 566 consenting patients were contemporaneously randomised: 189 SOC + DocP and 377 SOC + AAP. The patients, balanced by allocated treatment were: 342 (60%) M1; 429 (76%) Gleason 8–10; 449 (79%) WHO performance status 0; median age 66 years and median PSA 56 ng/ml. With median follow-up 4 years, 149 deaths were reported. For overall survival, HR = 1.16 (95% CI 0.82–1.65); failure-free survival HR = 0.51 (95% CI 0.39–0.67); progression-free survival HR = 0.65 (95% CI 0.48–0.88); metastasis-free survival HR = 0.77 (95% CI 0.57–1.03); prostate cancer-specific survival HR = 1.02 (0.70–1.49); and symptomatic skeletal events HR = 0.83 (95% CI 0.55–1.25). In the safety population, the proportion reporting ≥1 grade 3, 4 or 5 adverse events ever was 36%, 13% and 1% SOC + DocP, and 40%, 7% and 1% SOC + AAP; prevalence 11% at 1 and 2 years on both arms. Relapse treatment patterns varied by arm. Conclusions This direct, randomised comparative analysis of two new treatment standards for hormone-naïve prostate cancer showed no evidence of a difference in overall or prostate cancer-specific survival, nor in other important outcomes such as symptomatic skeletal events. Worst toxicity grade over entire time on trial was similar but comprised different toxicities in line with the known properties of the drugs. Trial registration Clinicaltrials.gov: NCT00268476.

Common variation at 1q24.1 (ALDH9A1) is a potential risk factor for renal cancer

So far six susceptibility loci for renal cell carcinoma (RCC) have been discovered by genome-wide association studies (GWAS). To identify additional RCC common risk loci, we performed a meta-analysis of published GWAS (totalling 2,215 cases and 8,566 controls of Western-European background) with imputation using 1000 Genomes Project and UK10K Project data as reference panels and followed up the most significant association signals [22 single nucleotide polymorphisms (SNPs) and 3 indels in eight genomic regions] in 383 cases and 2,189 controls from The Cancer Genome Atlas (TCGA). A combined analysis identified a promising susceptibility locus mapping to 1q24.1 marked by the imputed SNP rs3845536 (P combined =2.30x10-8). Specifically, the signal maps to intron 4 of the ALDH9A1 gene (aldehyde dehydrogenase 9 family, member A1). We further evaluated this potential signal in 2,461 cases and 5,081 controls from the International Agency for Research on Cancer (IARC) GWAS of RCC cases and controls from multiple European regions. In contrast to earlier findings no association was shown in the IARC series (P=0.94; P combined =2.73x10-5). While variation at 1q24.1 represents a potential risk locus for RCC, future replication analyses are required to substantiate our observation.

Prostate Radiotherapy for Men with Metastatic Disease: A New Comparison in the STAMPEDE Trial

*Royal Marsden Hospitals Foundation Trust, Sutton, UK yMRC Clinical Trials Unit, London, UK z School of Medicine, Cardiff University, Cardiff, UK x The Christie and Salford Royal Hospitals Foundations Trusts, Manchester, UK { Inselspital, Bern, Switzerland jj School of Cancer Sciences, University of Birmingham, Birmingham, UK ** Institute of Cancer Research and Royal Marsden Hospitals Foundation Trust, Sutton, UK yy Institute of Cancer Science, Glasgow, UK

Response to ‘High Risk of Neutropenia for Hormone-naive Prostate Cancer Patients Receiving STAMPEDE-style Upfront Docetaxel Chemotherapy in Usual Clinical Practice’, by Tanguay et al.

Madam — Tanguay and colleagues presented data on patients treated with docetaxel [1]. We agree that the reported rates of neutropenia-based toxicities vary across the trials, as do the categories against which toxicities are reported.

754OIMPACT OF NODE STATUS AND RADIOTHERAPY ON FAILURE-FREE SURVIVAL IN PATIENTS WITH NEWLY DIAGNOSED NON-METASTATIC PROSTATE CANCER: DATA FROM >690 PATIENTS IN THE CONTROL ARM OF THE STAMPEDE TRIAL

Aim The natural history of patients (pts) with newly diagnosed high-risk non-metastatic (M0) prostate cancer receiving androgen deprivation therapy (ADT) either alone or with standard of care radiotherapy (RT) at 6 to 9 months is not well documented. Further, no RCT has tested RT in N + M0 patients; none are planned. The STAMPEDE RCT (NCT00268476; MRC PR08; CRUK/06/019) includes such pts & allows exploratory multivariate analysis of radical RTs impact. We report data from trial pts. We hypothesised that planning RT in N + M0 pts improves survival outcomes. Methods Newly diagnosed pts with confirmed M0 disease in the control arm (standard of care = ADT planned for >2yr), diagnosed <6 months pre-randomisation & on ADT for 0-12 weeks already, were identified from trial records in Jan-2014. RT is encouraged in this group, but only mandated for N0M0 pts since Nov-2011. We report failure-free survival (FFS), driven by PSA failure, & overall survival (OS); split by nodal involvement & reported RT status. Standard survival analysis methods were used, adjusting for age & PSA. Results 5272 men were recruited Oct-2005 to Jan-2014, including a cohort of 694 M0 pts with newly diagnosed disease allocated to the control arm: median age 66yr (IQR 61-71), median time from diagnosis to randomisation 2.6m (IQR 2.0-3.3) & median PSA 42ng/ml (IQR 17-88) at diagnosis. By Jan-2014, there were 34 deaths; 25 from prostate cancer. Median follow-up is short, but 2yr OS is 95% (95%CI 92, 97) & 2yr FFS is 79% (95%CI 75, 83). Median FFS is 63 months; 79% (94/119) report PSA failure-only as first FFS event. Time to FFS is worse in N+ pts (HR 1.87, 95%CI 1.29-2.72). Baseline characteristics were comparable by planned RT status, but N0M0 pts planned for RT had lower PSA at diagnosis & more WHO PS = 0. The Table shows that FFS outcomes clearly favour the planned use of RT.

Flexible trial design in practice: Dropping and adding arms in STAMPEDE (MRC PR08, CRUK/06/019)-A multiarm, multistage randomized controlled trial.

27 Background: STAMPEDE ( NCT00268476 ) is a multi-centre, RCT using novel multi-arm, multi-stage (MAMS) methods. We describe the methodological and practical issues arising with early stopping of recruitment to some arms following an intermediate analysis and the issues in adding new research arms during the trial. METHODS The trial recruits men with locally advanced or metastatic prostate cancer starting standard long-term hormone therapy. There are 5 research and 1 control arm assessed over 3 intermediate activity stages I-III [outcome measure: failure-free survival (FFS)] and a final efficacy stage IV [outcome measure: overall survival]. At the end of each stage, research arms are formally compared to the control arm. Accrual of further patients is discontinued early for research arms not showing sufficient evidence of activity or with adverse safety considerations; accrual continues to the other arms; this interim hurdle is increasingly stringent at each stage. The addition of new research arm(s) can be actively considered when sufficiently interesting agents emerge. New research arms are compared only to contemporaneously-recruited control arm pts using the same intermediate guidelines in a time-delayed manner. RESULTS (1) After the second intermediate activity analysis (Mar-2011), the IDMC recommended and the Trial Steering Committee ratified discontinuation of recruitment to two research arms for lack-of-sufficient activity. Nearly 100 recruiting centres in UK and Switzerland had to promptly implement changes. Detailed advanced preparation meant that activation was swift and recruitment continued seamlessly into Activity Stage III. (2) An application to add a new research arm, abiraterone, has been agreed by funders, industry partner and ethics committee; regulatory approval awaited. Details on methodological and practical issues and implementation of these changes will be presented. CONCLUSIONS The STAMPEDE experiences shows that recruitment to MAMS trials is achievable and that mid-flow changes to trial design are practicable and encouraged.

Radiotherapy to the primary tumour for newly diagnosed, metastatic prostate cancer (STAMPEDE): a randomised controlled phase 3 trial

Summary Background Based on previous findings, we hypothesised that radiotherapy to the prostate would improve overall survival in men with metastatic prostate cancer, and that the benefit would be greatest in patients with a low metastatic burden. We aimed to compare standard of care for metastatic prostate cancer, with and without radiotherapy. Methods We did a randomised controlled phase 3 trial at 117 hospitals in Switzerland and the UK. Eligible patients had newly diagnosed metastatic prostate cancer. We randomly allocated patients open-label in a 1:1 ratio to standard of care (control group) or standard of care and radiotherapy (radiotherapy group). Randomisation was stratified by hospital, age at randomisation, nodal involvement, WHO performance status, planned androgen deprivation therapy, planned docetaxel use (from December, 2015), and regular aspirin or non-steroidal anti-inflammatory drug use. Standard of care was lifelong androgen deprivation therapy, with up-front docetaxel permitted from December, 2015. Men allocated radiotherapy received either a daily (55 Gy in 20 fractions over 4 weeks) or weekly (36 Gy in six fractions over 6 weeks) schedule that was nominated before randomisation. The primary outcome was overall survival, measured as the number of deaths; this analysis had 90% power with a one-sided α of 2·5% for a hazard ratio (HR) of 0·75. Secondary outcomes were failure-free survival, progression-free survival, metastatic progression-free survival, prostate cancer-specific survival, and symptomatic local event-free survival. Analyses used Cox proportional hazards and flexible parametric models, adjusted for stratification factors. The primary outcome analysis was by intention to treat. Two prespecified subgroup analyses tested the effects of prostate radiotherapy by baseline metastatic burden and radiotherapy schedule. This trial is registered with ClinicalTrials.gov, number NCT00268476. Findings Between Jan 22, 2013, and Sept 2, 2016, 2061 men underwent randomisation, 1029 were allocated the control and 1032 radiotherapy. Allocated groups were balanced, with a median age of 68 years (IQR 63–73) and median amount of prostate-specific antigen of 97 ng/mL (33–315). 367 (18%) patients received early docetaxel. 1082 (52%) participants nominated the daily radiotherapy schedule before randomisation and 979 (48%) the weekly schedule. 819 (40%) men had a low metastatic burden, 1120 (54%) had a high metastatic burden, and the metastatic burden was unknown for 122 (6%). Radiotherapy improved failure-free survival (HR 0·76, 95% CI 0·68–0·84; p<0·0001) but not overall survival (0·92, 0·80–1·06; p=0·266). Radiotherapy was well tolerated, with 48 (5%) adverse events (Radiation Therapy Oncology Group grade 3–4) reported during radiotherapy and 37 (4%) after radiotherapy. The proportion reporting at least one severe adverse event (Common Terminology Criteria for Adverse Events grade 3 or worse) was similar by treatment group in the safety population (398 [38%] with control and 380 [39%] with radiotherapy). Interpretation Radiotherapy to the prostate did not improve overall survival for unselected patients with newly diagnosed metastatic prostate cancer. Funding Cancer Research UK, UK Medical Research Council, Swiss Group for Clinical Cancer Research, Astellas, Clovis Oncology, Janssen, Novartis, Pfizer, and Sanofi-Aventis.

Reply to Che-Kai Tsao, Matthew D. Galsky, and William K. Oh's Platinum Opinion. Docetaxel for Metastatic Hormone-Sensitive Prostate Cancer: Urgent Need To Minimize The Risk Of Neutropenic Fever. Eur Urol 2016;70:707–708

Dr Tsao and colleagues recently discussed their experiences with neutropenic fever in patients treated with docetaxel for hormone-sensitive prostate cancer [1]. This is an important potential complication that they contextualize within the efficacy benefits reported from three randomised controlled trials of these data so far. We note that others have also reported higher rates in routine practice with their early experiences of docetaxel in this setting, including Tanguay et al [2]. Tsao et al note that this may be because clinical trials have ‘‘relatively narrowly defined eligibility criteria’’ and may ‘‘bear only slight resemblance to the general population of patients with mPCa’’. However, it may be that eligibility criteria are not the only issue in any non-generalisability. Many trials set out to be as inclusive as possible. For example, the STAMPEDE trial defined broad eligibility criteria with inclusive intent that should allow randomisation of patients who would be sufficiently fit for chemotherapy if it were allocated into the randomisation. It is possible that sites do not or cannot fully recruit from across the eligibility spectrum, preferentially excluding some patients. This could affect generalisability even for a trial with broad eligibility criteria and broad intent. The results apply to the type of patient actually recruited to the trial rather than to the type of patient that was planned to join the trial. This can happen in any trial and for various reasons. Ideally, sites should support and facilitate recruitment to trials from all across their eligibility spectrum. Where this is not possible or is not accepted, there should be a responsibility to make this explicit to the trials team. For example, a site may systematically exclude a subpopulation (eg, older or less fit patients) either because they are not being approached or because they are declining randomisation. The results of a trial apply to the type of population recruited rather than the population intended. Any extrapolation beyond the recruited population must be undertaken with care.