Skeletal-related events after abiraterone or enzalutamide in patients with metastatic castration-resistant prostate cancer: A population-based study using the SEER-Medicare linked dataset.

BACKGROUND: Skeletal-related events (SREs) from bone metastases disease carry significant morbidity in men with metastatic castration resistant prostate cancer (mCRPC). The differential risk of SREs among patients receiving abiraterone acetate (AA) or enzalutamide (ENZ) is unknown. METHODS: To compare the risk of SREs among men with mCRPC receiving AA or ENZ, a retrospective cohort study using the SEER-Medicare Linked Database was conducted. Men with prostate cancer aged ≥65 years at first AA or ENZ prescription (index date) from 2011 to 2015 were identified. Patients were followed until the earliest occurrence of SRE, death, Medicare disenrollment, or December 31, 2016. The primary outcome was a composite endpoint of SRE (pathologic fracture, spinal cord compression, or surgery or radiation to bone) after the index date. Multivariable logistic regressions including key demographic and clinical covariates with death as a competing risk were conducted. RESULTS: Overall, 5,856 patients were identified (4,207 received AA and 1,649 received ENZ). Median age was 76.5 years (IQR 71.4-82.3), 4,557 (77.8%) were White, 1,112 (19.2%) had recent chemotherapy, and 2,730 (46.6%) had recent zoledronic acid or denosumab. Eight-hundred and thirty-seven (14.3%) patients had ≥1 SRE after index date. In multivariable analyses, there was no difference in SRE risk based on AA and ENZ (HR=0.99 for ENZ, 95%CI 0.84-1.16, P=0.890). Denosumab was associated with lower SRE risk (HR=0.75, 95%CI 0.64-0.88, P=0.001). CONCLUSIONS: In this large cohort of men with mCRPC, there was no difference in risk of SRE between AA and ENZ. Decision-making should be informed by prior therapies, comorbidities, toxicity profiles, and patient preferences. Denosumab has evidence of benefit in preventing SREs in this real-world population.

Accelerating cancer clinical trial recruitment through a financial reimbursement program integrated with patient navigation: an interrupted time series analysis.

BACKGROUND: Cancer treatment clinical trials face major challenges with patient recruitment. Strategies to address patient indirect costs associated with clinical trial participation may accelerate accrual overall. The current study examined the effect of the IMproving Patient Access to Clinical Trials (IMPACT) intervention on patient accrual to cancer treatment clinical trials at an academic medical center. The IMPACT intervention was an onsite patient navigator combined with a financial reimbursement program to address patient out of pocket costs and began on September 2018. METHODS: This analysis measured frequency of patient enrollment in cancer treatment clinical trials and available cancer treatment clinical trials per month between January 1, 2016 and March 31, 2020. An interrupted time-series analysis (ITSA) was conducted to estimate changes in patient enrollment attributable to the IMPACT intervention. RESULTS: During the study period, a mean of 69 patients enrolled in clinical trials per month (standard deviation (SD = 13), with 27 (SD = 7) in early phase vs 41 (SD = 12) in late phase clinical trials. The number of available clinical trials per month was 51 (SD = 2) overall, with 23 (SD = 1) in early phase vs 28 (SD = 1) in late phase context. A total of 3470 patients were enrolled in cancer treatment clinical trials during the evaluated time period, the majority of whom were men (1895, 55 %) and racially white (2267, 65 %). A statistically significant increase in the number of patients accrued as compared to the pre-intervention trend was observed; with approximately 1 additional patient accrued per month, with a larger effect on increase patient accrual for late phase clinical trials. DISCUSSION: This study observed that the IMPACT intervention accelerated clinical trial recruitment, especially among late phase clinical trials. Future research will examine strategies to leverage this infrastructure to optimize recruitment among underrepresented patients. POLICY SUMMARY: To improve clinical trial recruitment and ensure that trial results are representative of a diverse population it is critical for health policies consider patient out-of-pocket costs and potential reimbursement to alleviate financial burden associated with clinical trial participation. Furthermore, policies for facilitating clinical trial recruitment and participant retention should budget for and incorporate a navigation component to assist patients who may not be familiar with the healthcare system and available financial assistance.

Survival of African-American and Caucasian men after sipuleucel-T immunotherapy: outcomes from the PROCEED registry.

PURPOSE: African Americans experience greater prostate cancer risk and mortality than do Caucasians. An analysis of pooled phase III data suggested differences in overall survival (OS) between African American and Caucasian men receiving sipuleucel-T. We explored this in PROCEED (NCT01306890), an FDA-requested registry in over 1900 patients with metastatic castration-resistant prostate cancer (mCRPC) treated with sipuleucel-T. PATIENTS AND METHODS: OS for patients who received ≥1 sipuleucel-T infusion was compared between African American and Caucasian men using an all patient set and a baseline prostate-specific antigen (PSA)-matched set (two Caucasians to every one African American with baseline PSAs within 10% of each other). Univariable and multivariable analyses were conducted. Survival data were examined using Kaplan-Meier and Cox proportional hazard methodologies. RESULTS: Median follow-up was 46.6 months. Overall survival differed between African American and Caucasian men with hazard ratios (HR) of 0.81 (95% confidence interval [CI]: 0.68-0.97, P = 0.03) in the all patient set and 0.70 (95% CI: 0.57-0.86, P < 0.001) in the PSA-matched set. Median OS was longer in African Americans than in Caucasian men for both analysis sets, e.g., 35.3 and 25.8 months, respectively, in the PSA-matched set. Similar results were observed in the all patient set. Differences were larger when treatment began at lower baseline PSA; curves were more similar among patients with higher baseline PSA. In patients with baseline PSA below the median, the HR was 0.52 (95% CI: 0.37-0.72, P < 0.001), with median OS of 54.3 versus 33.4 months. Known prognostic factors and African American race (multivariable analyses; HR: 0.60, 95% CI: 0.48-0.74, P < 0.001) were independently associated with OS. Use of post-sipuleucel-T anticancer interventions was balanced between races. CONCLUSION: In this exploratory analysis of a registry including nearly 12% African American men with mCRPC, OS was significantly different between African Americans and Caucasians, indicating further research is warranted.

Assessment of 68Ga-PSMA-11 PET Accuracy in Localizing Recurrent Prostate Cancer: A Prospective Single-Arm Clinical Trial.

IMPORTANCE: In retrospective studies, 68Ga-PSMA-11 positron emission tomographic (PET) imaging improves detection of biochemically recurrent prostate cancer compared with conventional imaging. OBJECTIVE: To assess 68Ga-PSMA-11 PET accuracy in a prospective multicenter trial. DESIGN, SETTING, AND PARTICIPANTS: In this single-arm prospective trial conducted at University of California, San Francisco and University of California, Los Angeles, 635 patients with biochemically recurrent prostate cancer after prostatectomy (n = 262, 41%), radiation therapy (n = 169, 27%), or both (n = 204, 32%) underwent 68Ga-PSMA-11 PET. Presence of prostate cancer was recorded by 3 blinded readers on a per-patient and per-region base. Lesions were validated by histopathologic analysis and a composite reference standard. MAIN OUTCOMES AND MEASURES: Endpoints were positive predictive value (PPV), detection rate, interreader reproducibility, and safety. RESULTS: A total of 635 men were enrolled with a median age of 69 years (range, 44-95 years). On a per-patient basis, PPV was 0.84 (95% CI, 0.75-0.90) by histopathologic validation (primary endpoint, n = 87) and 0.92 (95% CI, 0.88-0.95) by the composite reference standard (n = 217). 68Ga-PSMA-11 PET localized recurrent prostate cancer in 475 of 635 (75%) patients; detection rates significantly increased with prostate-specific antigen (PSA): 38% for <0.5 ng/mL (n = 136), 57% for 0.5 to <1.0 ng/mL (n = 79), 84% for 1.0 to <2.0 ng/mL (n = 89), 86% for 2.0 to <5.0 ng/mL (n = 158), and 97% for ≥5.0 ng/mL (n = 173, P < .001). Interreader reproducibility was substantial (Fleiss κ, 0.65-0.78). There were no serious adverse events associated with 68Ga-PSMA-11 administration. PET-directed focal therapy alone led to a PSA drop of 50% or more in 31 of 39 (80%) patients. CONCLUSIONS AND RELEVANCE: Using blinded reads and independent lesion validation, we establish high PPV for 68Ga-PSMA-11 PET, detection rate and interreader agreement for localization of recurrent prostate cancer. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT02940262 and NCT03353740.

Low testosterone at first prostate-specific antigen failure and assessment of risk of death in men with unfavorable-risk prostate cancer treated on prospective clinical trials.

BACKGROUND: Low testosterone at the time of diagnosis of prostate cancer has been associated with a worse prognosis. Whether this is true and how to define the best treatment approach at the time of first prostate-specific antigen (PSA) failure to the authors' knowledge has not been elucidated to date and was studied herein. METHODS: Between 1995 and 2001, a total of 58 men with unfavorable-risk PC who were treated on clinical trials with radiotherapy and androgen deprivation therapy (ADT) had available testosterone levels at the time of PSA failure. Cox and Fine and Gray regressions were performed to ascertain whether low versus normal testosterone was associated with the risk of PC-specific mortality, other-cause mortality, and all-cause mortality adjusting for age, salvage ADT, and known PC prognostic factors. RESULTS: After a median follow-up of 6.68 years after PSA failure, 31 men (53.4%) had died; 10 of PC (32.3%), of which 8 of 11 (72.7%) versus 2 of 47 (4.3%) deaths occurred in men with low versus normal testosterone at the time of PSA failure, respectively. A significant increase in the risk of all-cause mortality (adjusted hazard ratio [AHR], 2.54; 95% confidence interval [95% CI], 1.04-6.21 [P = .04]) and PC-specific mortality (AHR, 13.71; 95% CI, 2.4-78.16 [P = .003]), with a reciprocal trend toward a decreased risk of other-cause mortality (AHR, 0.18; 95% CI, 0.02-1.55 [P = .12]) was observed in men with low versus normal testosterone. CONCLUSIONS: Low, but not necessarily castrate, testosterone levels at the time of PSA failure confer a very poor prognosis. These observations provide evidence to support testosterone testing at the time of PSA failure. Given prolonged survival when abiraterone or docetaxel is added to ADT in men with castrate-sensitive metastatic PC and possibly localized high-risk PC provides a rationale supporting their use with ADT in men with low testosterone in the setting of a phase 2 trial. Cancer 2018;124:1383-90. © 2017 American Cancer Society.

Department of Defense prostate cancer clinical trials consortium: a new instrument for prostate cancer clinical research.

BACKGROUND: In 2005, the US Department of Defense, through the US Army Medical Research and Materiel Command, Office of the Congressionally Directed Medical Research Programs, created a funding mechanism to form a clinical trials consortium to conduct phase I and II studies in prostate cancer. This is the first report of the Prostate Cancer Clinical Trials Consortium (PCCTC). PATIENTS AND METHODS: The Department of Defense award supports a consortium of 10 prostate cancer research centers. Memorial Sloan-Kettering Cancer Center was awarded the Coordinating Center grant for the consortium and charged with creating an infrastructure to conduct early-phase multicenter clinical trials. Each participating center was required to introduce >or=1 clinical trial per year and maintain accrual of a minimum of 35 patients per year. RESULTS: The PCCTC was launched in 2006 and now encompasses 10 leading prostate cancer research centers. Fifty-one trials have been opened, and 1386 patients have been accrued at member sites. Members share an online clinical trial management system for protocol tracking, electronic data capture, and data storage. A legal framework has been instituted, and standard operating procedures, an administrative structure, editorial support, centralized budgeting, and mechanisms for scientific review are established. CONCLUSION: The PCCTC fulfills a congressional directive to create a clinical trials instrument dedicated to early-phase prostate cancer studies. The member institutions have built an administrative, informatics, legal, financial, statistical, and scientific infrastructure to support this endeavor. Clinical trials are open and accruing in excess of federally mandated goals.