Real-world outcomes of sipuleucel-T treatment in PROCEED, a prospective registry of men with metastatic castration-resistant prostate cancer

BACKGROUND

The large registry, PROVENGE Registry for the Observation, Collection, and Evaluation of Experience Data (PROCEED)(NCT01306890), evaluated sipuleucel-T immunotherapy for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC).

METHODS

PROCEED enrolled patients with mCRPC receiving 3 biweekly sipuleucel-T infusions. Assessments included overall survival (OS), serious adverse events (SAEs), cerebrovascular events (CVEs), and anticancer interventions (ACIs). Follow-up was for ≥3 years or until death or study withdrawal.

RESULTS

In 2011-2017, 1976 patients were followed for 46.6 months (median). The median age was 72 years, and the baseline median prostate-specific antigen level was 15.0 ng/mL; 86.7% were white, and 11.6% were African American. Among the patients, 1902 had 1 or more sipuleucel-T infusions. The median OS was 30.7 months (95% confidence interval [CI], 28.6-32.2 months). Known prognostic factors were independently associated with OS in a multivariable analysis. Among the 1255 patients who died, 964 (76.8%) died of prostate cancer (PC) progression. The median time from the first infusion to PC death was 42.7 months (95% CI, 39.4-46.2 months). The incidence of sipuleucel-T-related SAEs was 3.9%. The incidence of CVEs was 2.8%, and the rate per 100 person-years was 1.2 (95% CI, 0.9-1.6). The CVE incidence among 11,972 patients with mCRPC from the Surveillance, Epidemiology, and End Results-Medicare database was 2.8%; the rate per 100 person-years was 1.5 (95% CI, 1.4-1.7). One or more ACIs (abiraterone, enzalutamide, docetaxel, cabazitaxel, or radium 223) were received by 77.1% of the patients after sipuleucel-T; 32.5% and 17.4% of the patients experienced 1- and 2-year treatment-free intervals, respectively.

CONCLUSIONS

PROCEED provides contemporary survival data for sipuleucel-T-treated men in a real-world setting of new life-prolonging agents, which will be useful in discussing treatment options with patients and in powering future trials with sipuleucel-T. The safety and tolerability of sipuleucel-T in PROCEED were consistent with previous findings.

Treatment Duration, Healthcare Resource Utilization, and Costs Among Chemotherapy-Naïve Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Enzalutamide or Abiraterone Acetate: A Retrospective Claims Analysis

Introduction

Enzalutamide and abiraterone acetate (plus prednisone) are new hormonal treatments for metastatic castration-resistant prostate cancer (mCRPC). This study compared treatment duration, healthcare resource utilization (HRU), and treatment costs for chemotherapy-naïve mCRPC patients treated with enzalutamide or abiraterone acetate in the USA.

Methods

Chemotherapy-naïve mCRPC patients initiating treatment with enzalutamide or abiraterone acetate were identified from administrative claims. Continuous enrollment ≥ 6 months before and ≥ 3 months after the index date (initiation date of enzalutamide or abiraterone acetate) was required. Treatment duration, all-cause and prostate cancer-related HRU, and costs were estimated during the post-index period. Multivariable analyses compared HRU and costs between cohorts, adjusting for baseline characteristics.

Results

Overall, 920 chemotherapy-naïve patients initiated enzalutamide and 2310 initiated abiraterone acetate (median follow-up, 10.7 and 13.5 months, respectively). More enzalutamide-treated patients had corticosteroid-sensitive comorbidities at baseline. Treatment duration was longer with enzalutamide versus abiraterone acetate (median, 10.7 vs. 8.8 months; P = 0.008). Enzalutamide was associated with fewer all-cause inpatient admissions [adjusted incidence rate ratio (95% confidence interval) 0.87 (0.76, 0.99)], days of hospitalization [0.84 (0.70, 1.02)], and outpatient visits [0.94 (0.90, 0.98)], and fewer prostate cancer-related outpatient visits [0.92 (0.87, 0.96)] compared with abiraterone acetate. Enzalutamide was also associated with lower prostate cancer-related inpatient and emergency department costs [adjusted differences, $122 (P = 0.024) and $28 (P = 0.009), respectively].

Conclusion

Chemotherapy-naïve mCRPC patients treated with enzalutamide versus abiraterone acetate had longer treatment duration and incurred lower HRU and prostate cancer-related inpatient and emergency department costs.

Funding

Astellas Pharma Inc.

Electronic supplementary material

The online version of this article (10.1007/s12325-018-0774-1) contains supplementary material, which is available to authorized users.

Treatment duration and utilization patterns in metastatic castration-resistant prostate cancer patients receiving enzalutamide or abiraterone acetate

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Background: Enzalutamide (ENZA) and abiraterone acetate (ABI) are approved hormonal therapies for men with metastatic castration-resistant prostate cancer (mCRPC). This study assessed real-world treatment duration and utilization patterns in patients receiving ENZA or ABI. Methods: Adult mCRPC patients initiating ENZA or ABI before or after cytotoxic chemotherapy were identified from the Truven MarketScan® claims database (2012–2015). The index date was the first initiation of ENZA or ABI; continuous insurance enrollment for ≥6 months prior to and ≥3 months after the index date was required. Treatment discontinuation was defined as a prescription gap of ≥45 days. Median treatment duration was estimated using Kaplan–Meier method. Treatment switching was defined as starting a new mCRPC-related therapy within 30 days before to 45 days after the discontinuation date. Analyses were separately conducted for chemo-naïve and chemo-experienced patients. Results: The study included 3230 chemo-naive (ENZA 920; ABI 2310) and 692 chemo-experienced patients (ENZA 262; ABI 430). Among chemo-naive patients, ENZA cohort was older (mean age 74.5 vs 73.5; p = 0.013), with a higher proportion of comorbidities vs ABI cohort. Treatment duration was longer for ENZA cohort than ABI cohort (log-rank p = 0.008; median = ENZA 10.7 vs ABI 8.8 months). Within 1 year of initiation, 55.7% of ENZA and 60.8% of ABI cohort discontinued treatment and 22.5% and 34.7%, respectively, switched to other mCRPC therapies. Results were consistent among subgroups with specific comorbidities. Treatment duration was shorter among chemo-experienced patients than chemo-naïve; the difference between ENZA vs ABI among chemo-experienced patients was not statistically significant (log-rank p = 0.255; median = ENZA 7.5 vs ABI 7.1 months). Conclusions: Despite a more complex profile at baseline, chemo-naive mCRPC patients in the ENZA cohort had a longer treatment duration and lower proportion of switching to other prostate-cancer-directed therapies vs the ABI cohort. The difference of treatment duration between the two cohorts was not statistically significant for chemo-experienced patients.

Health care resource utilization and costs in metastatic castration-resistant prostate cancer patients treated with enzalutamide or abiraterone acetate

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Background: Cost of care is an important component of valuation of novel treatments in oncology. Enzalutamide (ENZA) and abiraterone acetate (ABI) are approved hormonal agents for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This study compared healthcare resource utilization (HRU) and costs for patients treated with ENZA or ABI in the U.S. Methods: Adult mCRPC patients initiating ENZA or ABI before and or after cytotoxic chemotherapy were identified from the Truven MarketScan claims database (2012–2015). The first claim of ENZA or ABI was defined as the index date; continuous enrollment ≥6 months before and ≥3 months after the index date was required. HRU and costs were estimated during the post-index period for both cohorts. Generalized linear models compared HRU and costs between the cohorts and were adjusted for baseline demographic and clinical covariates. Analyses were separately conducted for chemo-naïve and chemo-experienced patients. Results: The study included 3230 chemo-naive patients (ENZA 920; ABI 2310) and 692 chemo-experienced patients (ENZA 262; ABI 430). Among chemo-naive patients, ENZA cohort was older (mean age: 74.5 vs 73.5; p=0.013), with a higher proportion of baseline comorbidities vs ABI cohort. During the post-index period, ENZA cohort had fewer all-cause inpatient admissions (IPA) [adjusted incidence rate ratio (IRR) 0.87; p=0.033], all-cause outpatient visits (OPV) [adjusted IRR 0.94; p=0.004], and PC-related OPV (adjusted IRR 0.92; p<0.001) vs the ABI cohort. Within 3 months of the index date, ENZA cohort was less likely to have an all-cause IPA (adjusted odds ratio [OR] 0.75; p=0.029). In addition, ENZA cohort had lower PC-related IPA and emergency department (ED) costs vs ABI cohort. The differences of HRU and medical costs between the 2 cohorts were not statistically significant for chemo-experienced patients. Conclusions: Despite a higher comorbidity burden at baseline, chemo-naive mCRPC patients treated with ENZA incurred less HRU and lower PC-related IPA and ED costs vs ABI cohort. Differences between the 2 cohorts were not statistically significant for chemo-experienced patients.

Polymer delivered, subcutaneously administered leuprolide acetate provides stable and long-term drug delivery and testosterone suppression in 4 pivotal trials

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Background: Prostate cancer patients receive androgen deprivation therapy (ADT) to suppress testosterone (T) to prevent proliferation of cancer cells. T suppression levels achieved by bilateral orchiectomy remain the gold standard for the target of suppression by ADT. Although the historical threshold definition of castration is T ≤ 50 ng/dL, increasing evidence suggests T lower than 20ng/dL may improve clinical outcomes, e.g., an increased cancer specific survival and delayed disease progression. To determine the minimal threshold of serum leuprolide required to maintain castrate level T suppression in prostate cancer patients, data from 4 pivotal trials evaluating long-acting, subcutaneously (SC) administered leuprolide acetate (LA) formulated with a biodegradable polymer were pooled. Methods: 438 eugonadal prostate cancer patients (age 40-86) were treated with SC-LA at 7.5, 22.5, 30, or 45mg delivered with a single dose lasting over 1, 3, 4, or 6 months (n = 120, 117, 90, 111), respectively in 4 open-label, fixed-dose, pivotal trials. Descriptive statistics were used to summarize the median concentration of leuprolide acetate at each time point as well as to determine level of T suppression. Results: Over the dosing intervals of the 1, 3, 4 and 6-month SC-LA formulations, median serum leuprolide levels were consistent and median serum T remained below T < 20 ng/dL. In the pooled analysis (n = 86), 99% of patients with LA ≥ 0.1 ng/mL after injection achieved castration after 4 Weeks. Conclusions: These data suggest that SC-LA achieves consistent and prolonged drug delivery resulting in sufficient serum LA levels to provide favorable T suppression below 20 ng/dL, which may have clinical outcomes, e.g., increased cancer specific and progression free survival.

Integrating the Genomic Prostate Score into Clinical Practice Workflow

INTRODUCTION

A dilemma that urologists face is how to determine which patients with prostate cancer need immediate intervention and which patients can be safely placed on active surveillance. Gene expression profile analysis of biopsy tissue has been proposed as a means of providing more accurate risk stratification for low risk prostate cancer. However, there is a general lack of acceptance and standardization around the integration of genomic testing in clinical practice. The Oncotype DX® prostate cancer assay is a commercially available tissue based assay that assesses the expression of key genes across multiple biological pathways predictive of prostate cancer aggressiveness from the diagnostic biopsy specimen, and reports an individual Genomic Prostate Score.

METHODS

With the recommendations set forth in this article we aim to standardize operational best practices for the integration of the Genomic Prostate Score into clinical practice. Its purpose is to provide practical guidance to help physicians understand, run, interpret and communicate actionable results to patients.

RESULTS

The Genomic Prostate Score reflects the biology of the underlying tumor to help guide initial treatment decisions at the time of biopsy. This article is based on real-world evidence from the authors' respective experiences at their institutions and practices. The authors were carefully selected based on their depth of experience and knowledge about the Genomic Prostate Score and, as such, it is their expertise that is being leveraged to support the best practices algorithm.

CONCLUSIONS

This article provides easy to use, clear-cut and practical guidance for physicians on how to use the Genomic Prostate Score to inform decisions regarding active surveillance.

Changing characteristics of patients treated with sipuleucel-T (sip-T) over time: Real-world experience from the PROCEED registry

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Background: Sip-T is an autologous cellular immunotherapy approved by the FDA for the treatment of asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer. PROCEED (NCT01306890) is a phase 4 registry evaluating men receiving sip-T therapy in the US. Patient characteristics and treatment trends were assessed from 2011 to 2013, when several agents with an overall survival benefit became commercially available. Methods: For patients enrolled from 2011 to 2013, baseline patient and disease characteristics at the first sip-T infusion, trends in prior therapy, and pre–sip-T baseline prostate-specific antigen (PSA) levels were examined year over year. Results: From 2011 to 2013, 1902 patients were enrolled and received ≥ 1 sip-T infusion: 2011, n = 145; 2012, n = 967; 2013, n = 790. During this time period, enrollment of African American men nearly doubled from 6.9% to 13.4%, and central venous catheter use to facilitate sip-T infusion decreased (from 53.8% to 44.1%). Median baseline lactate dehydrogenase (LDH) levels and the number of lymph node metastases also decreased as well as median baseline PSA values (17.8 ng/mL to 11.9 ng/mL [P = 0.002]). Prior use of first-generation anti-androgens (from 73.1% to 60.5%), ketoconazole (17.2% vs. 6.3%), and estrogen (4.8% vs. 1.6%) decreased along with prior docetaxel use (19.3% vs. 7.5%). In contrast, prior investigational use of abiraterone acetate (from 3.4% to 8.9%) and enzalutamide (1.4% vs. 3.2%) increased over time. Conclusions: Over the duration of PROCEED, the decrease in baseline PSA, lower LDH, fewer nodal metastases, and decline in prior docetaxel use suggest that sip-T is being used earlier in the course of metastatic castration-resistant disease. Moreover, second-line hormonal therapy use with agents that do not improve overall survival appears to be substituted by therapies that do. This decrease in second-line hormonal therapies during PROCEED could suggest a real-world preference for earlier sip-T use. Clinical trial information: NCT01306890.

Impact of prior docetaxel (D) on sipuleucel-T (sip-T) product parameters in PROCEED patients (pts)

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Background: Sip-T is an autologous cellular immunotherapy indicated for asymptomatic or minimally symptomatic mCRPC. The IMPACT trial excluded pts who received D ≤3 months prior to registration. PROCEED is an ongoing, phase IV registry, enrolling pts treated with commercial sip-T. Use of D prior to sip-T is not restricted, so prior D affect on sip-T immune manufacturing parameters can be evaluated. Methods: Pts treated with sip-T ≤ 6 mo were eligible to provide informed consent. Sip-T parameters assessed included: total nucleated cell (TNC) count, antigen presenting cell (APC) count (CD54+large cells) and APC activation (upregulation of CD54). Results: By Nov. 2012, 108/761 (14%) received D prior to sip-T and had similar median cumulative APC counts (1.83 [Q1, Q3: 1.16, 2.71] vs. 1.82 [1.27, 2.70] x 109) and TNC counts (10.16 [7.30, 13.69] vs. 11.47 [8.56, 15.31] x 109) vs. D naïve, whereas median cumulative APC activation appeared slightly lower (32.39 [25.05, 41.02] vs. 34.84 [28.71, 42.83]), but was well above the release criterion for each infusion (2.6 fold). The group was then split by Eastern Cooperative Oncology Group Performance Status (ECOG PS) and Gleason scores (Table). Conclusions: Pts with D prior to sip-T appeared to have product parameters comparable to pts without prior D, albeit with a slightly lower APC activation. Further analysis showed that pts receiving D within 3 months of sip-T had higher Gleason and ECOG scores. The clinical significance of these findings is unclear, but suggests that APC activation is not impaired following docetaxel. Clinical trial information: NCT01306890. [Table: see text]

Surveillance for recurrent bladder cancer using a point-of-care proteomic assay

CONTEXT

At least 50% of patients with a history of bladder cancer have recurrences, so rigorous surveillance is necessary. Cystoscopy is standard but can fail to detect some bladder cancers, so a urine test is frequently part of the evaluation.

OBJECTIVE

To investigate whether a point-of-care proteomic test that measures the nuclear matrix protein NMP22 in voided urine could improve detection of recurrence during monitoring of patients with a history of bladder cancer.

DESIGN, SETTING, AND PATIENTS

From September 2001 to February 2002, 23 academic, private practice, and hospital facilities in 9 US states prospectively enrolled 668 consecutive patients with a history of bladder cancer in this cross-sectional study. Patients provided a voided urine sample for analysis of NMP22 protein and cytology prior to cystoscopy.

MAIN OUTCOME MEASURES

Diagnosis of bladder cancer recurrence, based on cystoscopy with biopsy, was accepted as the reference standard. The performance of the NMP22 test was compared with voided urine cytology as an aid to detection. Testing for the NMP22 tumor marker was conducted in a blinded manner.

RESULTS

Bladder cancer was diagnosed in 103 patients. Cystoscopy alone identified 91.3% of the cancers (94/103; 95% confidence interval [CI], 84.1%-95.9%). The combination of cystoscopy with the NMP22 assay detected 99.0% of the malignancies (102/103; 95% CI, 94.7%-100%; P = .005). The NMP22 assay detected 8 of 9 cancers that were not visualized during initial cystoscopy, including 7 that were high-grade. The sensitivity and specificity of the NMP22 test alone were 49.5% (51/103; 95% CI, 39.5%-59.5%) and 87.3% (493/565; 95% CI, 84.2%-89.9%), respectively. Voided cytology detected only 3 of the malignancies missed during initial cystoscopy and did not significantly increase the sensitivity of cystoscopy (94.2%; 95% CI, 87.7%-97.8%; P = .08).

CONCLUSION

The noninvasive point-of-care assay for elevated urinary NMP22 protein can increase the ability to detect recurrent bladder cancer, with test results available during the patient visit.

Randomized comparative study of 3 versus 8-month neoadjuvant hormonal therapy before radical prostatectomy: biochemical and pathological effects

PURPOSE

A prospective phase 3 trial was initiated to determine whether 8 compared with 3-month neoadjuvant hormonal therapy reduces prostate specific antigen (PSA) recurrence rates after radical prostatectomy. Our interim analysis includes secondary end points of differences in biochemistry, pathology and adverse events between the 2 groups.

MATERIALS AND METHODS

Men with clinically confined prostate cancer were randomized to receive 7.5 mg. leuprolide intramuscularly monthly and 250 mg. flutamide orally 3 times daily for 3 or 8 months before radical prostatectomy. Our study was powered to detect a 35% decrease in PSA recurrence, assuming a 30% recurrence rate in the 3-month arm after 3 years.

RESULTS

A total of 547 men were randomized between August 1995 and April 1998. Men in the 8 and 3-month groups were equally stratified for T stage (29% T1c, 70% T2), Gleason grade (68% less than 4, 32% 4 or greater) and pretreatment PSA (63% less than 10, 27% 10 to 20 and 10% greater than 20 microg./l.). Mean pretreatment PSA was slightly higher in the 8-month compared with the 3-month group (11.64 versus 9.95 microg./l., respectively, p = 0.0539). A total of 44 men withdrew from study before surgery and, therefore, were nonevaluable. Preoperative PSA nadir was less than 0.1 microg./l. in 43.3% versus 75.1% (p <0.0001), and 0.3 microg./l. or greater in 21% versus 9.2% after 3 versus 8 months, respectively (p <0.0006). Mean serum PSA decreased 98% to 0.12 microg./l. after 3 months, with a further 57% to 0.052 microg./l. from 3 to 8 months. Transrectal ultrasound determined that prostatic volume decreased 37% from a mean of 40.6 to 25.4 cc after 3-month neoadjuvant hormonal therapy (p = 0.0001) and a further 13% to 22.2 cc after 8 months (p = 0.03). Mean hemoglobin decreased 15% (148.2 to 125.4 gm./dl.) after 3-month neoadjuvant hormonal therapy but stabilized thereafter. Radical prostatectomy was completed in 500 men, while surgery was aborted intraoperatively in 3. Positive margin rates were significantly lower in the 8 than 3-month group (12% versus 23%, respectively, p = 0.0106). There were no fatal adverse events and no differences between the 2 groups in the severity or causality (p = 0.287, 0.0564) of adverse events, or incidence of increased liver enzymes or diarrhea (p = 0.691, 0.288, respectively). However, men in the 8-month group noticed a higher number of newly reported adverse events (4.5 versus 2.9, p <0.0001) and higher incidence of hot flushes than the 3-month group (87% versus 72%, respectively, p <0.0001).

CONCLUSIONS

Ongoing biochemical and pathological regression of prostate tumors occurs between 3 and 8 months of neoadjuvant hormonal therapy, suggesting that the optimal duration of neoadjuvant hormonal therapy is longer than 3 months. Longer followup is needed to determine whether longer therapy alters PSA recurrence rates.