The development of ProMark was guided by experts in the field of prostate oncology and pathology, and focused, from its inception, on addressing the unmet need for better information for the decision specifically in men with Gleason 3+3 and 3+4 disease. ProMark was validated through a series of studies from initial proof of concept to final marker model lock-down and validation trials. In total, the development of ProMark involved more than 1,200 patients in a rigorous, 3-phase program. An overview of the analytical development and validation program for ProMark is outlined below:
- The ProMark analytic platform was validated through a lethal outcomes study of 340 patient cases from multiple centers which successfully demonstrated performance of the proprietary quantitative multiplex (QMPI) technology
- The ProMark biomarker selection process took place in 3-stages beginning with an initial list of 160 potential biomarker candidates from which 39 candidates were progressed to full clinical performance evaluation in a large multicenter retrospective study.
- The biomarker selection study identified a set of 12 biomarkers that were highly robust to sampling error, demonstrating performance across low and high Gleason TMA to predict Prostate Cancer aggressiveness and lethal outcome
- A multicenter ProMark clinical development study then analyzed the performance of the 12 biomarkers, and established the final 8 biomarker set ProMark, and developed and locked down the ProMark risk score algorithm on these final 8 biomarkers
- Two clinical validation studies have demonstrated the performance to predict Prostate Cancer pathology and long term outcome at the time of biopsy
Below is the list of the 8 protein markers that comprise the final ProMark assay and which are incorporated in the validated ProMark algorithm to generate a patient's ProMark Risk Score.
Blume-Jensen, Peter, et al. Development and Clinical Validation of an In Situ Biopsy-Based Multimarker Assay for Risk Stratification in Prostate Cancer. Clinical Cancer Research (2015).
Purpose: Prostate cancer aggressiveness and appropriate therapy are routinely determined following biopsy sampling. Current clinical and pathologic parameters are insufficient for accurate risk prediction leading primarily to overtreatment and also missed opportunities for curative therapy.
Experimental Design: An 8-biomarker proteomic assay for intact tissue biopsies predictive of prostate pathology was defined in a study of 381 patient biopsies with matched prostatectomy specimens. A second blinded study of 276 cases validated this assay's ability to distinguish "favorable" versus "nonfavorable" pathology independently and relative to current risk classification systems National Comprehensive Cancer Network (NCCN and D'Amico).
Results: A favorable biomarker risk score of =0.33, and a nonfavorable risk score of >0.80 (possible range between 0 and 1) were defined on "false-negative" and "false-positive" rates of 10% and 5%, respectively. At a risk score =0.33, predictive values for favorable pathology in very low-risk and low-risk NCCN and low-risk D'Amico groups were 95%, 81.5%, and 87.2%, respectively, higher than for these current risk classification groups themselves (80.3%, 63.8%, and 70.6%, respectively). The predictive value for nonfavorable pathology was 76.9% at biomarker risk scores >0.8 across all risk groups. Increased biomarker risk scores correlated with decreased frequency of favorable cases across all risk groups. The validation study met its two coprimary endpoints, separating favorable from nonfavorable pathology (AUC, 0.68; P < 0.0001; OR, 20.9) and GS-6 versus non-GS-6 pathology (AUC, 0.65; P < 0.0001; OR, 12.95).
Conclusion: The 8-biomarker assay provided individualized, independent prognostic information relative to current risk stratification systems, and may improve the precision of clinical decision making following prostate biopsy.
Saad, Fred et al. Biopsy-based Proteomic Assay Predicts Risk of Biochemical Recurrence after Radical Prostatectomy. The Journal of Urology (2016)
Purpose: Current clinicopathologic parameters are insufficient to predict the likelihood of biochemical recurrence in patients with Prostate Cancer after radical prostatectomy. Such information may help to identify patients who would likely benefit from adjuvant radiotherapy rather than active surveillance. A multiplex proteomic assay, previously tested on biopsies and found to be predictive of favorable or unfavorable pathology at radical prostatectomy, was assessed for its predictive value to identify patients at higher risk of biochemical relapse.
Materials and Methods: Proteomic assays from core needle biopsies from 288 men who subsequently underwent radical prostatectomy at the Centre hospitalier de l'Université de Montréal were evaluated for prediction of subsequent biochemical recurrence.
Results: Of the 288 men, biochemical relapse was observed in 47 (16.3%) and metastases in 5 (1.7%). Median follow up was 68.5 months. The proteomic assay clearly separated patients into three categories - low, intermediate and high risk of biochemical relapse (p=0.0007). Assay scores predicted biochemical relapse in univariate analysis (hazard ratio: 1.724, p=0.0002 per 20% change in score), significantly better than other pre-operative prognostic parameters. Additionally, the assay score had a significantly higher p-value when combined with clinical NCCN stage compared to stage alone (hazard ratio: 1.579, p=0.0017 per 20% change in score).
Conclusion: A protein-based assay score derived from diagnostic needle biopsy has strong predictive ability for biochemical relapse after surgery. These results suggest that this assay score can be used at the diagnostic stage to identify patients whose Prostate Cancer is potentially more biologically aggressive and in whom active treatment should be considered.
Peabody, John W, et al. Prostate Cancer Assay Improves Treatment Decisions for Early Stage Prostate Cancer Patients. AVBCC (2015)
Introduction: Of the 240,000 men in the US diagnosed annually with Prostate Cancer, the majority have indolent tumors. Distinguishing between aggressive and indolent cancer is an important clinical challenge. The current approaches for assessing tumor aggressiveness are recognized to be insufficient. ProMark is a novel protein-based assay with demonstrated ability to predict tumor aggressiveness at biopsy. The objective of this study is to measure the clinical utility of ProMark in the management of early-stage Prostate Cancer.
Methods: 86 board-certified urologists were enrolled in a randomized, two-arm experiment that collected data using clinical vignettes: simulated patient cases wherein doctors are provided with results to any tests or procedures they choose to order and are asked to make a treatment plan based upon their investigations. To measure changes in practice, participants completed cases at baseline (R1) and 3 at round 2 (R2). After baseline data were collected, the urologists randomized to the intervention arm received a 15-minute training on ProMark and then, for their R2 cases, were given ProMark results. The cases were all newly diagnosed Gleason 3+3 and 3+4 Prostate Cancer patients. Each case had a treatment course of either active surveillance (AS) or active treatment (AT), determined from the literature and NCCN guidelines. The outcome measure was the appropriate treatment, defined as urologists who ordered a biopsy and correctly indicated Active Surveillance or Aggressive Treatment, according to the individual case. Analyses were done using difference in difference estimations.
Results: The introduction of ProMark resulted in a marked increase in the number of urologists instituting the correct treatment. While the control group scores for appropriate treatment stayed virtually the same across the rounds (15.1% R1 vs. 13.6% R2; p>0.1), appropriate treatment in the intervention group increased from 12% in R1 to 28% in R2. This change was most marked in the confirmatory (+23%) (p<0.01)) and switch cases (+21%) types (p<.01) but was not statistically significant for the clinically indeterminate cases.
Conclusions: In a randomized, experimental study, a novel protein based assay significantly increased the number of patients who were put on the appropriate treatment and suggests that this type of testing has demonstrable clinical utility and may potentially generate significant savings.
Clinical Cancer Research, 2015 Mar 2. pii: clincanres.2603.2014
Proteome Science, Shipitsin et al. Proteome Science 2014, 12:40
British Journal of Cancer, (2014) 111, 1201-1212 | doi: 10.1038/bjc.2014.396
The Oncologist, 10.1634/theoncologist.2015-0214.doi: 10.1634/theoncologist.2014-0167
Distinguishing aggressive versus nonaggressive Prostate Cancer using a novel prognostic proteomics biopsy test, ProMark.
Presented as poster at 2014 ASCO Annual Meeting