Evaluation of Prostate-Specific Antigen Declines for Surrogacy in Patients Treated on SWOG 99-16

Petrylak, Daniel P.; Ankerst, Donna P.; Jiang, Caroline S.; Tangen, Catherine M.; Hussain, Maha; Lara, Primo N.; Jones, Jeffrey A.; Taplin, Mary Ellen; Burch, Patrick A.; Kohli, Manish; Benson, Mitchell C.; Small, Eric J.; Raghavan, Derek; Crawford, E. David

doi:10.1093/jnci/djj129

Cited by 270 publications

(189 citation statements)

References 14 publications

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“…Notably, our findings are similar to previously published results of the TAX327 and SWOG 99-06 studies in which PSA decline of 30% within 3 months of treatment initiation provided surrogacy for OS. 10,11 The presented 30% cutoff had a higher degree of statistical surrogacy than traditional 50% cutoff by using the most stringent surrogacy criterion, the proportion of treatment effect explained (PTE) in SWOG 99-06. 12 In this study, we found that 13% of men with CRPC had biopsy Gleason 6 disease at diagnosis.…”

Section: Discussionmentioning

confidence: 99%

Clinical predictors of survival in men with castration‐resistant prostate cancer

Nakabayashi

Hayes

Taplin

et al. 2013

Cancer

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BACKGROUND: This study sought to characterize Modern patients with castration-resistant prostate cancer (CRPC) and identify pretreatment clinical predictors of survival. METHODS: A cohort of men with CRPC with and without metastases (M) treated with secondary hormonal therapy (2eHT) and/or chemotherapy (CT) was identified from the authors' institutional database. Associations of patient and disease characteristics at diagnosis, at androgen-deprivation therapy (ADT) initiation, at CRPC index date, and survival were evaluated. CRPC index date was defined as the start date of either 2eHT or CT, whichever came first. RESULTS: In the cohort of 622 men, 434 men (70%) had M-positive disease; 552 men (89%) received 2eHT and 70 men (11%) received CT as their initial CRPC treatment. There were 410 deaths (66%) at the time of analysis. Median overall survival (OS) was 35 months (quartile 1, quartile 3: 21 months, 61 months). In multivariate analyses, higher biopsy Gleason score, the presence of M at ADT initiation, shorter time from ADT start to CRPC, higher prostate-specific antigen and poorer Eastern Cooperative Oncology Group performance status at CRPC and M at CRPC were predictive of shorter OS. Interestingly, whereas some men with biopsy Gleason scores of 6 died of their disease (N 5 42), they had a longer OS after CRPC compared with those with a Gleason score 7. CONCLUSIONS: This large retrospective study of patients with CRPC in a tertiary cancer center shows that biopsy Gleason score of 6 is associated with a less aggressive CRPC course, and the impact that M at ADT initiation and CRPC have on outcome is quantified.

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Section: Discussionmentioning

confidence: 99%

Clinical predictors of survival in men with castration‐resistant prostate cancer

Nakabayashi

Hayes

Taplin

et al. 2013

Cancer

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“…Thus, the changes of PSA concentrations in patients treated with hormonal therapy may be associated with the reduction of tumor mass with different kinetics compared to cytotoxic chemotherapy. Despite the fact that the decrease of PSA concentration is usually less dramatic after cytotoxic chemotherapy compared to hormonal treatment, the change of PSA concentration is an established surrogate endpoint in patients with castration-resistant prostate cancer treated with docetaxel (10) . However, the daily clinical practice has taught us that the changes of serum PSA concentrations must be interpreted with caution as a phenomenon of PSA surge denoting a rise of concentrations with subsequent decline has been described (11,12) .…”

Section: Bohuslav Melicharmentioning

confidence: 99%

Tumor biomarkers: PSA and beyond

Melichar

2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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“…A pivotal assessment of PSA as a surrogate for OS was performed as part of the Southwest Oncology Group (SWOG) 99-16 study, 6 in which patients with androgen-independent prostate cancer were assigned treatment with docetaxel/estramustine or mitoxantrone/prednisone. The group receiving docetaxel gained a 2-3 month OS benefit.…”

Section: Appraisal Of End Points In Phase II and Iii Trials In Castramentioning

confidence: 99%

Measuring therapeutic efficacy in the changing paradigm of castrate-resistant prostate cancer

Mulders

Schalken

2009

Prostate Cancer Prostatic Dis

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One of the current challenges in the evaluation of novel agents for the treatment of advanced prostate cancer is the identification of a surrogate end point for overall survival (OS). Prostatespecific antigen (PSA) levels have been used as a screening tool and a biomarker of response to both hormonal and cytotoxic agents. However, PSA levels do not seem to be a suitable surrogate end point for OS in trials of targeted agents for castrate-resistant prostate cancer (CRPC). These findings suggest the need for adopting measures of efficacy that more accurately reflect the mechanisms of action of these agents in phase II trials, in order to realize improvements in OS in the phase III setting. The Prostate Cancer Clinical Trials Working Group (PCWG2) have recently made recommendations for the design of future trials and advised that PSA levels should not be the sole criterion on which to base clinical decisions. Here, we appraise the end points that have been used in phase II and III trials in patients with CRPC, and highlight the need for the adoption of the PCWG2 guidelines, the recommendations of which include radiographic imaging, in addition to bone scintigraphy, and symptomatic or radiographic disease progression criteria.

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Evaluation of Prostate-Specific Antigen Declines for Surrogacy in Patients Treated on SWOG 99-16

Abstract: Several PSA measures satisfied the surrogacy criteria for survival in a retrospective analysis of data from SWOG 99-16. However, these measures await prospective validation in future clinical trials of chemotherapy in men with androgen-independent prostate cancer.

Cited by 270 publications

References 14 publications

Clinical predictors of survival in men with castration‐resistant prostate cancer

Clinical predictors of survival in men with castration‐resistant prostate cancer

Tumor biomarkers: PSA and beyond

Measuring therapeutic efficacy in the changing paradigm of castrate-resistant prostate cancer

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