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

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 229-229
Author(s):  
Vahan Kassabian ◽  
Scott Flanders ◽  
Samuel Wilson ◽  
Bruce A. Brown ◽  
Yan Song ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Treatment Duration ◽  
Index Date ◽  
Abiraterone Acetate ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Kaplan Meier ◽  
Utilization Patterns ◽  
The Difference ◽  
Hormonal Therapies

229 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.

Gaps in treatment amongst metastatic castration resistant prostate cancer (mCRPC) patients taking abiraterone acetate or enzalutamide.

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 334-334
Author(s):  
Ajay Behl ◽  
Lorie Ellis ◽  
Dominic Pilon ◽  
Yongling Xiao ◽  
Patrick Lefebvre ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Index Date ◽  
Drug Dosage ◽  
Abiraterone Acetate ◽  
Data Availability ◽  
Castration Resistant Prostate Cancer ◽  
Cancer Treatments ◽  
Loss To Follow Up ◽  
Castration Resistant ◽  
Kaplan Meier

334 Background:Abiraterone acetate (ABI) and enzalutamide (ENZ) are novel oral therapies offering survival benefit to metastatic castration-resistant prostate cancer (mCRPC) patients. The efficacy of cancer treatments rely on patient consistency and adherence to recommended dosage regimens. Factors such as drug-drug interactions and intolerance or toxicities can result in patients or their providers reducing the drug dosage. This study aims to describe treatment discontinuation patterns observed for ABI and ENZ. Methods: The Truven Health MarketScan Research Databases were used to conduct a retrospective analysis of mCRPC patients initiated on ABI or ENZ (index date) between 10/01/2012 to 12/31/2014 with ≥6 months of continuous eligibility prior to index date and a PC diagnosis during the period of continuous eligibility. Patients were observed until loss to follow-up, or end of data availability. Kaplan-Meier (KM) survival curves were used to compare the rates of having a refill gap (i.e., ≥14 days, ≥30 days, or ≥60 days) in patients initiated on ABI or ENZ. Results: The table below summarizes the KM probabilities of having a refill gap among patients initiated on ABI or ENZ. Conclusions: Significantly higher rates of refill gaps ≥30 days and ≥ 60 days were observed for patients initiating ENZ as compared to ABI after 6 months of observation in this initial analysis. Additional research is needed to understand the reasons for gaps in treatment in patients treated with mCRPC therapies. [Table: see text]

scholarly journals Minireview: Androgen Metabolism in Castration-Resistant Prostate Cancer

2013 ◽  
Vol 27 (5) ◽  
pp. 708-714 ◽  
Author(s):  
Nima Sharifi
Keyword(s):  
Prostate Cancer ◽  
Abiraterone Acetate ◽  
Castration Resistant Prostate Cancer ◽  
Synthesis Inhibitor ◽  
Androgen Independence ◽  
Androgen Synthesis ◽  
Androgen Receptor Antagonist ◽  
Castration Resistant ◽  
Hormonal Therapies ◽  
Additional Clinical Benefit

Abstract The decades-old terminology of androgen independence has been replaced in recent years with castration-resistant prostate cancer. Biological and clinical evidence have together conspired to support the use of this revised terminology by demonstrating that in the vast majority of cases tumors are neither truly depleted of androgens, nor are they free of the requirement for androgens to sustain growth and progression. Abiraterone acetate, an androgen synthesis inhibitor, and enzalutamide, a potent androgen receptor antagonist, both exploit the continued requirement for androgens. A central question, given the therapeutic gains enabled by further suppression of the androgen axis with these newer agents, is whether there may be additional clinical benefit gained by moving the goal posts of androgen suppression even further. The answer lies in part with the mechanisms utilized by tumors that enable resistance to these therapies. The aims of this review were to give a broad outline of steroidogenesis in prostate cancer and to highlight recent developments in understanding resistance to hormonal therapies.

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

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 232-232
Author(s):  
Vahan Kassabian ◽  
Scott Flanders ◽  
Samuel Wilson ◽  
Bruce A. Brown ◽  
Yan Song ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Resource Utilization ◽  
Index Date ◽  
Linear Models ◽  
Abiraterone Acetate ◽  
Cost Of Care ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Cohort Differences ◽  
Comorbidity Burden

232 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.

Overall survival by race in chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone acetate or enzalutamide.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 212-212 ◽  
Author(s):  
Megan Ann McNamara ◽  
Daniel J. George ◽  
Krishnan Ramaswamy ◽  
Stanislav Lechpammer ◽  
Jack Mardekian ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Overall Survival ◽  
Retrospective Study ◽  
Index Date ◽  
Abiraterone Acetate ◽  
Cox Proportional Hazards ◽  
Veterans Health ◽  
Health Administration ◽  
Castration Resistant Prostate Cancer ◽  
Kaplan Meier

212 Background: Prostate cancer (PC) is the most common malignancy among US men and the 2nd leading cause of cancer-related death. African Americans (AAs) have higher mortality from mCRPC than Whites (W). Despite this disparity, a small prior study suggested AAs may have better PSA response to abiraterone acetate (ABAC) than Ws, though radiographic progression did not differ. We evaluated overall survival (OS) in AA vs W chemotherapy-naïve (CN) mCRPC patients (Ps) treated with ABAC or enzalutamide (ENZ). Methods: This was a retrospective study that used the Veterans Health Administration (VHA) database. Male PC Ps (≥18 years) who had surgical or medical castration were identified from Apr 1, 2013 to Mar 31, 2018. The index date was the first prescription claim date for ABAC or ENZ following castration. Ps had no chemotherapy for 12 months pre-index date and had continuous VA health plan enrollment for ≥12 months pre- and post-index date. Ps were followed until death or disenrollment. Unadjusted and Kaplan-Meier survival analyses adjusted for demographic and clinical characteristics were used to calculate survival time, and multivariate Cox proportional hazards models assessed the relationship between race and OS. Results: This study included 2,123 W and 787 AA mCRPC Ps with mean ages of 74 and 71 years, respectively. The median follow‐up time was 570 days and 561 days for AA and W, respectively. AA were more prone to comorbid hypertension (77.1% vs 67.1%; p<.0001), type II diabetes (38.1% vs 29.3%; p<.0001), and liver damage or abnormality (8.8% vs 5.2%; p=0.0003) than W . From the unadjusted analysis, the median Kaplan-Meier estimated OS was 910 days for AAs and 784 days for Ws; AAs had better OS than Ws (HR=0.887; 95%CI [0.790-0.996]). From the adjusted analysis, the median Kaplan-Meier estimated OS was 918 days for AAs and 781 days for Ws; AAs still had better OS (HR=0.826; 95%CI [0.732-0.933]). Conclusions: This large retrospective study provides the first evidence that AA CN mCRPC Ps may have better OS with ABAC or ENZ than W Ps. Trials are needed to validate this finding and explore the mechanisms of racial disparities in outcomes with new hormonal therapies.

Abiraterone acetate in patients with metastatic castration-resistant prostate cancer: Long term outcome of the Temporary Authorization for Use program in France.

2015 ◽  
Vol 33 (7_suppl) ◽  
pp. 264-264
Author(s):  
Nadine Houede ◽  
Philippe Beuzeboc ◽  
Sophie Gourgou ◽  
Diego Tosi ◽  
Laura Moise ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Treatment Duration ◽  
Hormonal Treatment ◽  
Abiraterone Acetate ◽  
Castration Resistant Prostate Cancer ◽  
First Line ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Castration Resistant

264 Background: COU-AA-301 trial has proved that abiraterone acetate (AA), a selective inhibitor of androgen biosynthesis, improved overall survival (OS) of patients with metastatic castration resistant prostate cancer (mCRPC) after a first line of docetaxel. Based on this result, a temporary use authorisation (TUA) was performed between December 2010 and July 2011 to provide patients with mCRPC the opportunity to receive AA before its commercialization. The aim of this study was to evaluate safety and efficacy of AA treatment in this TUA. Methods: Between December 2010 and July 2011, we conducted an ambispective, multicentric cohort study and investigated data from 20 centres participating to the AA TUA for patients presenting mCRPC and already treated by a first line of chemotherapy (CT). Statistical analyses of the data were performed using the Stata software v13 to identify predictive and prognostic factors. Results: Among the 408 patients, 306 were eligible with a follow-up at 3 years. Median OS was 37.1 months from beginning of CT and 14.6 months from AA introduction. 211 patients (69%) received ≥ 3 months of AA and 95 patients (31%) were treated less than 3 months. In the multivariate analyses, duration of AA was significantly correlated with PSA decrease at 3 months. Additionally, shorter time under AA treatment, presence of multiple sites of metastasis and previous hormonal treatment duration were three independent factors associated with poorer OS. At the time of analysis ten patients were still under treatment for more than 3 years. Conclusions: Biochemical response monitored by PSA changes at 3 months is a strong predictive factor for AA treatment duration. Some high responders’ patients could beneficiate from AA for more than 3 years.

Impact of number of lines of therapy following docetaxel (D) in metastatic castration-resistant prostate cancer (mCRPC).

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 223-223 ◽  
Author(s):  
Guru Sonpavde ◽  
Menaka Bhor ◽  
Daniel Hennessy ◽  
Debajyoti Bhowmik ◽  
Liji Shen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Alkaline Phosphatase ◽  
Specific Antigen ◽  
Abiraterone Acetate ◽  
Drug Group ◽  
Castration Resistant Prostate Cancer ◽  
Optimal Sequence ◽  
Castration Resistant ◽  
Kaplan Meier ◽  
The Impact

223 Background: The impact of number of lines of therapy on outcomes following docetaxel (D) in metastatic castration-resistant prostate cancer (mCRPC) is unclear. We examined outcomes with cabazitaxel (C) and/or abiraterone acetate (A), following D during a period when all three therapies were available. We previously reported that most patients received only two of these three therapies. Among patients who received all three, DCA was administered more commonly and exhibited better overall survival (OS) than DAC after controlling for prognostic factors. Here, we report the impact of number of lines of therapy following D. Methods: A retrospective analysis of the U.S. Oncology network electronic health records (EHR) was conducted of post-D patients with mCRPC who received C and/or A from April 2011 to May 2012. Median OS was analyzed by Kaplan-Meier method. Cox proportional hazard models were used to evaluate impact on OS of number of therapies administered, age, Prostate Cancer Working Group (PCWG2) subtype, Charlson comorbidity index, prostate-specific antigen (PSA), alkaline phosphatase, hemoglobin, narcotic use, and treatment duration. Results: Multivariate analysis showed significantly lower mortality in the three-drug group compared to the two-drug group (HR 0.209 95% CI: 0.092-0.476, p<0.05). 113 patients received three drugs (DCA=77, DAC=36) and 237 received two drugs (DA=183, DC=54). The three-drug cohort was significantly younger than the two-drug group (median age 69 vs. 73). Other significant covariates (p<0.05) for mortality were narcotic use (HR 2.010 [1.240-3.259]), PSA (HR 1.014 [1.001-1.027] and alkaline phosphatase (HR 1.001 [1.000-1.001]. Conclusions: In men with mCRPC receiving C and/or A post-D, patients receiving all three therapies were younger and exhibited significantly better OS after controlling for clinical factors. In those receiving only two therapies, there appeared to be no difference in outcomes for second-line C versus A. Given the favorable impact of receiving all three therapies, more frequent administration of DCA in the three-drug group and better OS for DCA compared to DAC, we hypothesize that DCA may be a more optimal sequence. These results are exploratory and prospective validation is necessary.

scholarly journals Survival outcomes in patients with chemotherapy-naive metastatic castration-resistant prostate cancer treated with enzalutamide or abiraterone acetate

2021 ◽  
Author(s):  
Scott T. Tagawa ◽  
Krishnan Ramaswamy ◽  
Ahong Huang ◽  
Jack Mardekian ◽  
Neil M. Schultz ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Retrospective Analysis ◽  
Index Date ◽  
Abiraterone Acetate ◽  
Cox Proportional Hazards ◽  
Veterans Health ◽  
Health Administration ◽  
Castration Resistant Prostate Cancer ◽  
Risk Of Death ◽  
Castration Resistant

Abstract Objective Evaluation of the comparative effectiveness of enzalutamide and abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC) is limited to meta-analyses of randomized trials that exclude patients with significant comorbidities. We evaluated overall survival (OS) in patients with chemotherapy-naive mCRPC treated with enzalutamide or abiraterone acetate (abiraterone) in a real-world single payer setting. Methods A retrospective analysis (4/1/2014–3/31/2018) of the Veterans Health Administration (VHA) database was conducted. Patients with mCRPC had ≥1 pharmacy claim for enzalutamide or abiraterone (first claim date = index date) following disease progression on surgical/medical castration, without chemotherapy <12 months prior to index date. Patients had continuous VHA enrollment for ≥12 months pre-index date and were followed until death, disenrollment, or end of study. Kaplan–Meier analysis and multivariable Cox proportional hazards regression models examined the OS treatment effect. Results Patients with chemotherapy-naive mCRPC (N = 3174; enzalutamide, n = 1229; abiraterone, n = 1945) had mean ages of 74 and 73 years, respectively. Median follow-up was 18.27 and 19.07 months with enzalutamide and abiraterone, respectively. Enzalutamide-treated patients had longer median treatment duration than abiraterone-treated patients (9.93 vs 8.47 months, respectively, p = 0.0008). After baseline comorbidity adjustment, enzalutamide-treated patients had a 16% reduced risk of death (hazard ratio [HR] = 0.84; 95% CI, 0.76–0.94; p = 0.0012). For patients who remained on first line-therapy only, enzalutamide-treated patients had improved OS versus abiraterone-treated patients (HR = 0.71; 95% CI, 0.62–0.82). Enzalutamide-treated patients who crossed over to abiraterone had a comparable risk of death versus abiraterone-treated patients who crossed over to enzalutamide (HR = 0.91; 95% CI, 0.74–1.13). These results were confirmed by sensitivity analysis, which considered prognostic variables. Conclusions Retrospective analysis of the VHA database indicated that chemotherapy-naive patients with mCRPC initiating therapy with enzalutamide had improved survival versus abiraterone.

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