Clinical annotations for prostate cancer research: Defining data elements, creating a reproducible analytical pipeline, and assessing data quality.

BACKGROUND: Routine clinical data from clinical charts are indispensable for retrospective and prospective observational studies and clinical trials. Their reproducibility is often not assessed. We developed a prostate cancer-specific database for clinical annotations and evaluated data reproducibility. METHODS: For men with prostate cancer who had clinical-grade paired tumor-normal sequencing at a comprehensive cancer center, we performed team-based retrospective data collection from the electronic medical record using a defined source hierarchy. We developed an open-source R package for data processing. With blinded repeat annotation by a reference medical oncologist, we assessed data completeness, reproducibility of team-based annotations, and impact of measurement error on bias in survival analyses. RESULTS: Data elements on demographics, diagnosis and staging, disease state at the time of procuring a genomically characterized sample, and clinical outcomes were piloted and then abstracted for 2261 patients (with 2631 samples). Completeness of data elements was generally high. Comparing to the repeat annotation by a medical oncologist blinded to the database (100 patients/samples), reproducibility of annotations was high; T stage, metastasis date, and presence and date of castration resistance had lower reproducibility. Impact of measurement error on estimates for strong prognostic factors was modest. CONCLUSIONS: With a prostate cancer-specific data dictionary and quality control measures, manual clinical annotations by a multidisciplinary team can be scalable and reproducible. The data dictionary and the R package for reproducible data processing are freely available to increase data quality and efficiency in clinical prostate cancer research.

Prevalence of pain and analgesic use in men with metastatic prostate cancer using a patient-reported outcome measure.

PURPOSE: Contemporary tumor-directed therapies for metastatic castration-resistant prostate cancer (mCRPC) are approved to prolong life, but their effects on symptoms such as pain are less well understood as a result of the lack of analytically valid assessments of pain prevalence and severity, clinically meaningful definitions of therapeutic benefit, and methodologic standards of trial conduct. This study establishes pain characteristics in the mCRPC population using a PRO measure. MATERIALS AND METHODS: Patients with prostate cancer participated in an anonymous survey at five US comprehensive cancer centers in the Prostate Cancer Clinical Trials Consortium that incorporated the Brief Pain Inventory (BPI), analgesic use, and interference with daily activities. Prevalence and severity of cancer-related pain and analgesic use were tabulated according to castration-resistant status and exposure to docetaxel chemotherapy. RESULTS: Four hundred sixty-one patients with prostate cancer participated, of whom 147 had mCRPC involving bone (61% [89 of 147] docetaxel exposed, 39% [58 of 147] docetaxel naive). Pain of any level was more common among docetaxel-exposed versus docetaxel-naive patients with mCRPC (70% [62 of 89] v 38% [22 of 58], respectively; P<.001). BPI score≥4 was reported by 38% (34 of 89) of docetaxel-pretreated and 24% (14 of 58) of docetaxel-naive patients with mCRPC; 40% of these patients with pain intensity≥4 reported no current narcotic analgesic. CONCLUSION: Pain prevalence and severity were higher in patients with prior docetaxel exposure. Analgesics were underutilized. These results provide a method for estimating accruals along the disease continuum, and for enabling design of trials appropriately powered to assess pain.

Evidence for efficacy of new Hsp90 inhibitors revealed by ex vivo culture of human prostate tumors.

PURPOSE: Targeting Hsp90 has significant potential as a treatment for prostate cancer, but prototypical agents such as 17-allylamino-17 demethoxygeldanamycin (17-AAG) have been ineffective in clinical trials. Recently, a phase I study aimed at defining a biologically active dose reported the first response to an Hsp90 inhibitor in a patient with prostate cancer, which supports the development of new generation compounds for this disease. EXPERIMENTAL DESIGN: The biological actions of two new synthetic Hsp90 inhibitors, NVP-AUY922 and NVP-HSP990, were evaluated in the prostate cancer cell lines PC-3, LNCaP, and VCaP and in an ex vivo culture model of human prostate cancer. RESULTS: In cell lines, both NVP-AUY922 and NVP-HSP990 showed greater potency than 17-AAG with regard to modulation of Hsp90 client proteins, inhibition of proliferation, and induction of apoptotic cell death. In prostate tumors obtained from radical prostatectomy that were cultured ex vivo, treatment with 500 nmol/L of NVP-AUY922, NVP-HSP990, or 17-AAG caused equivalent target modulation, determined by the pharmacodynamic marker Hsp70, but only NVP-AUY922 and NVP-HSP990 showed antiproliferative and proapoptotic activity. CONCLUSIONS: This study provides some of the first evidence that new generation Hsp90 inhibitors are capable of achieving biologic responses in human prostate tumors, with both NVP-AUY922 and NVP-HSP990 showing potent on-target efficacy. Importantly, the ex vivo culture technique has provided information on Hsp90 inhibitor action not previously observed in cell lines or animal models. This approach, therefore, has the potential to enable more rational selection of therapeutic agents and biomarkers of response for clinical trials.

Randomized, open-label phase III trial of docetaxel plus high-dose calcitriol versus docetaxel plus prednisone for patients with castration-resistant prostate cancer.

PURPOSE: To compare the efficacy and safety of docetaxel plus high-dose calcitriol (DN-101) to docetaxel plus prednisone in an open-label phase III trial. PATIENTS AND METHODS: Nine hundred fifty-three men with metastatic castration-resistant prostate cancer (CRPC) were randomly assigned to Androgen-Independent Prostate Cancer Study of Calcitriol Enhancing Taxotere (ASCENT; 45 µg DN-101, 36 mg/m(2) docetaxel, and 24 mg dexamethasone weekly for 3 of every 4 weeks) or control (5 mg prednisone twice daily with 75 mg/m(2) docetaxel and 24 mg dexamethasone every 3 weeks) arms. The primary end point was overall survival (OS), assessed by the Kaplan-Meier method. RESULTS: At an interim analysis, more deaths were noted in the ASCENT arm, and the trial was halted. The median-follow-up for patients alive at last assessment was 11.7 months. Median OS was 17.8 months (95% CI, 16.0 to 19.5) in the ASCENT arm and 20.2 months (95% CI, 18.8 to 23.0) in the control arm (log-rank P = .002). Survival remained inferior after adjusting for baseline variables (hazard ratio, 1.33; P = .019). The two arms were similar in rates of total and serious adverse events. The most frequent adverse events were GI (reported in 75% of patients), and blood and lymphatic disorders (48%). Docetaxel toxicity leading to dose modification was more frequent in the ASCENT (31%) than in the control arm (15%). CONCLUSION: ASCENT treatment was associated with shorter survival than the control. This difference might be due to either weekly docetaxel dosing, which, in a prior study, showed a trend toward inferior survival compared with an every-3-weeks regimen, or DN-101 therapy.

High-dose calcitriol, zoledronate, and dexamethasone for the treatment of progressive prostate carcinoma.

BACKGROUND: Preclinical and clinical data have suggested that high-dose calcitriol (1,25-dihydroxycholecalciferol) has activity against prostate carcinoma. Pulse-dosed calcitriol and dexamethasone may maximize tolerability and efficacy. The authors examined the toxicity of pulse-dosed calcitriol with zoledronate and with the addition of dexamethasone at the time of disease progression. METHODS: Patients with progressive prostate carcinoma were eligible for the current study. In cohorts of 3-6 patients, calcitriol was administered for 3 consecutive days per week, starting at a dose of 4 microg per day. Doses were escalated to 30 microg per day. Intravenous zoledronate (4 mg) was administered monthly. Dexamethasone could be added to the regimen at disease progression. Toxicities, markers of bone turnover, plasma calcitriol levels, and clinical outcomes were recorded. RESULTS: Thirty-one patients were treated in cohorts that were defined by the calcitriol dose administered (4, 6, 8, 10, 14, 20, 24, or 30 microg). Seven patients received dexamethasone. Three patients had their doses reduced due to calcium-related laboratory findings. Patients tolerated therapy well, even in the 30 microg cohort; therefore, a maximum tolerated dose was not defined. Peak plasma levels observed in the 24 microg and 30 microg cohorts ranged from 391 to 968 pg/mL. Minimal antitumor effects were observed. CONCLUSIONS: Calcitriol was well tolerated at doses up to and including 30 microg 3 times per week in combination with intravenous zoledronate 4 mg monthly, with or without dexamethasone, in patients with progressive prostate carcinoma. Peak plasma levels in the 24 microg and 30 microg cohorts were greater than the levels associated with antitumor effects preclinically. Due to the cumbersome dosing schedule and the lack of significant activity observed, Phase II trials of this regimen are not planned.

Fully synthetic carbohydrate-based vaccines in biochemically relapsed prostate cancer: clinical trial results with alpha-N-acetylgalactosamine-O-serine/threonine conjugate vaccine.

PURPOSE: We report the synthesis of a mucin-related O-linked glycopeptide, alpha-N-acetylgalactosamine-O-serine/threonine (Tn), which is highly simplistic in its structure and can induce a relevant humoral response when given in a trimer or clustered (c) formation. We tested for an antitumor effect, in the form of a change in the posttreatment versus pretreatment prostate-specific antigen (PSA) slopes, that might serve as a surrogate for effectiveness of vaccines in delaying the time to radiographic progression. METHODS: We compared the antibody response to immunization with two conjugates, Tn(c)-keyhole limpet hemocyanin (KLH) and Tn(c)-palmitic acid (PAM) with the saponin immunologic adjuvant QS21, in a phase I clinical trial in patients with biochemically relapsed prostate cancer. Patients received Tn(c)-KLH vaccine containing either 3, 7, or 15 microg of Tn(c) per vaccination. Ten patients received 100 microg of Tn(c)-PAM. QS21 was included in all vaccines. Five vaccinations were administered subcutaneously during 26 weeks with an additional booster vaccine at week 50. RESULTS: Tn(c), when given with the carrier molecule KLH and QS21, stimulated the production of high-titer immunoglobulin M (IgM) and IgG antibodies. Inferior antibody responses were seen with T(c)-PAM. There was no evidence of enhanced immunogenicity with increasing doses of vaccine. An antitumor effect in the form of a decline in posttreatment versus pretreatment PSA slopes was also observed. CONCLUSION: A safe synthetic conjugate vaccine in a trimer formation was developed that can break immunologic tolerance by inducing specific humoral responses. It seemed to affect the biochemical progression of the disease as determined by a change in PSA log slope.

DNA vaccines: an active immunization strategy for prostate cancer.

Immunotherapy is currently being investigated as a treatment for patients with asymptomatic, recurrent prostate cancer manifested only by a rising prostate-specific antigen (PSA) level. Several different approaches to active immunization against antigens found on cancer cells have been explored. Immunization with DNA overcomes many of the obstacles noted in previous studies. Injection of plasmid DNA encoding a xenogeneic differentiation antigen (prostate-specific membrane antigen [PSMA]) is a potent means to induce antibody and T-cell responses to these otherwise poorly immunogenic self proteins. Use of the xenogeneic DNA (ie, human PSMA DNA injected into mouse) has been shown to be an absolute requirement to overcome immunologic tolerance. We are currently conducting a phase I trial of human and mouse PSMA DNA vaccines in patients with recurrent prostate cancer, based on preclinical experiments described below.