Abiraterone Acetate In Patients Research Articles

Long-Term Pharmacokinetic Follow-Up of Abiraterone Acetate in Patients with Metastatic Castration-Resistant Prostate Cancer.

This ABIGENE pharmacokinetic (PK) study sought mainly to characterize the unchanged drug PK during long-term abiraterone acetate (AA) administration in advanced prostate cancer patients (81 patients). It was observed that individual AA concentrations remained constant over treatment time, with no noticeable changes during repeated long-term drug administration for up to 120 days. There was no correlation between AA concentrations and survival outcomes. However, a significant association between higher AA concentrations and better clinical benefit was observed (p = 0.041). The safety data did not correlate with the AA PK data. A significant positive correlation (r = 0.40, p < 0.001) was observed between mean AA concentration and patient age: the older the patient, the higher the AA concentration. Patient age was found to impact steady-state AA concentration: the older the patient, the higher the mean AA concentration. Altogether, these data may help to guide future research and clinical trials in order to maximize the benefits of AA metastatic castration-resistant prostate cancer patients.

Real-World Incidence and Severity of Hypertension Caused by Abiraterone Acetate in Patients With Metastatic Prostate Cancer.

Abiraterone acetate (AA) is used in treatment of patients with metastatic prostate cancer. Despite the survival advantage, AA is associated with hypertension due to mineralocorticoid excess syndrome. We conducted a single-center retrospective analysis to evaluate the real-world incidence and severity of AA-induced hypertension. Electronic health records were used to collect baseline characteristics and prostate cancer history. Patient data, including blood pressure at each 4 (±2)-week interval, were collected for 24 weeks after the initiation of AA therapy. The primary endpoint was the incidence and severity of AA-induced hypertension. The secondary endpoints include effect of different prednisone dosing regimens and prostate cancer types on hypertensive incidence and the impact of clinical pharmacists' involvement in managing AA-induced hypertension. A total of 142 patients who met our inclusion criteria received AA for metastatic prostate cancer, 73 (51.4%) with metastatic castration-resistant prostate cancer (mCRPC), and 69 (48.6%) with metastatic castration-sensitive prostate cancer (mCSPC). Of all, 43.7% experienced all-grade hypertension, and 28.2% experienced grade 3-4 hypertension. There was no difference in incidence of hypertension between patients receiving 5 mg of prednisone daily and those receiving 5 mg of prednisone twice daily. All-grade hypertension occurred in 39.7% of mCRPC and 47.8% of mCSPC patients (P = 0.33). Thirty-two percent of patients were actively managed by a clinical pharmacist and had an overall trend of reduced hypertension severity after 12 weeks. This single-center, retrospective cohort study found that real-world metastatic prostate cancer patients who received AA had substantially higher incidence and severity of hypertension compared with clinical trials regardless of prednisone dose. In patients with mCRPC and mCSPC, the role of prednisone dose in hypertension incidence and severity warrants further investigation. Overall, results indicate the need for closely monitoring hypertension and optimization of anti-hypertensive therapy by multidisciplinary teams in metastatic prostate cancer patients receiving AA.

ARTO trial: Overall survival analysis from a randomized phase II trial testing the benefit of adding stereotactic body radiotherapy to abiraterone acetate in patients with oligometastatic castrate-resistant prostate cancer.

ARTO trial: Overall survival analysis from a randomized phase II trial testing the benefit of adding stereotactic body radiotherapy to abiraterone acetate in patients with oligometastatic castrate-resistant prostate cancer.

Neoadjuvant androgen deprivation therapy combined with abiraterone acetate in patients with locally advanced or metastatic prostate cancer: When to perform radical prostatectomy?

The surgical timing after neoadjuvant androgen-deprivation therapy (ADT) plus abiraterone acetate (AA) for patients with locally advanced or metastatic prostate cancer (PCa) is unknown. We divided patients with locally advanced or metastatic PCa into three groups according to prostate-specific antigen (PSA) nadir after neoadjuvant ADT plus AA: group 1 (PSA ≤ 0.2ng/ml), group 2 (0.2< PSA ≤ 4.0ng/ml), and group 3 (PSA > 4.0ng/ml).The median PSA baseline levels in groups 1, 2, 3 were 118.42 (32.03-457.78), 143.48 (17.7-8100.16), and153.35 (46.44-423.31) ng/ml, respectively. The median times of progression to CRPC in groups 1, 2,and 3 were 30, 26, and 26 months, respectively. Compared to patients with PSA nadir >0.2ng/ml, patients with PSA nadir <0.2ng/ml presented with longer PFS (p= 0.048).Our results suggested that, in patients with locally advanced or metastatic PCa, the time to progression to CRPC was longer after radical prostatectomy when PSA decreased below 0.2ng/ml using neoadjuvant ADT plus AA.

A phase I study of capivasertib in combination with abiraterone acetate in patients with metastatic castration-resistant prostate cancer.

85 Background: Androgen receptor (AR) targeting therapies prolong survival of patients with metastatic castration-resistant prostate cancer (mCRPC); however, in many cases, resistance develops, resulting in disease progression. Activation of the PI3K/AKT/mTOR signaling pathway is common in mCRPC and contributes to resistance, mostly due to loss of PTEN, which occurs in 40–60% of patients. Preclinical studies have demonstrated reciprocal regulation between the AR and PI3K/AKT/mTOR pathways and significant anti-tumor activity when both pathways are inhibited, particularly in models with PTEN-loss. Thus, a rationale exists to inhibit both pathways in mCRPC patients. We report interim results of a phase 1 multicohort study (NCT04087174) to confirm the acceptable dose of capivasertib, a potent, selective pan-AKT inhibitor in combination with the androgen synthesis inhibitor abiraterone acetate (AA) in mCRPC patients. Methods: Patients who had received at least one prior systemic therapy (chemotherapy or novel hormonal agent) for mCRPC were given AA (1000 mg, once daily) with capivasertib (400 mg, twice daily, 4 days on/3 days off) until unacceptable toxicity or disease progression. Dose-limiting toxicity in the first 28 days of treatment and adverse events were recorded. Results: 15 patients, median age 67 (range 49–82) years, were recruited in the USA and Spain. Twelve patients had received prior chemotherapy; 7 had two or more prior lines. Seven patients had received prior AA and 10 had received prior enzalutamide. No dose-limiting toxicities were recorded. Eight patients reported at least one grade ≥ 3 adverse event (AE). Grade ≥ 3 AEs in 7 patients were related to capivasertib: allergic reaction to medication, asthenia, type 2 diabetes mellitus, diarrhea and fatigue were each reported in 1 patient, maculopapular rash − in 2 patients, both hypokalemia and acquired Fanconi syndrome − in 1 patient. Acute kidney injury was reported in 4 patients but was not considered related to capivasertib. The most common AEs of any grade related to capivasertib were: diarrhea, 6/15 patients (40%); maculopapular rash, 5/15 (33%); fatigue, 4/15 (27%); hyperglycemia/type 2 diabetes mellitus, 4/15 (27%); nausea, 3/15 (20%); hypokalemia, 2/15 (13%); hypophosphatemia, 2/15 (13%). Capivasertib was discontinued in 4/15 patients (27%) due to AEs. Between initial screening and day 29 of treatment, 5 patients had reduced (&gt; 20%) PSA levels, with 3 patients showing sustained falls in PSA over 12 weeks. Conclusions: In this phase 1 study combined capivasertib and AA exhibits an acceptable safety and tolerability profile. Further data on the clinical efficacy and safety of the combination are being collected in the phase 3 CAPItello-281 trial. Acknowledgments: We thank Adam Errington, PhD, of Oxford PharmaGenesis, for medical writing assistance. Funding: This trial is funded by AstraZeneca. Clinical trial information: NCT04087174.

Abiraterone acetate in patients with metastatic castration-resistant prostate cancer, chemo-naive, who received a prior diethylstilbestrol therapy.

130 Background: The use of diethylstilbestrol (DES) for the treatment of metastatic castration resistant prostate cancer (mCRPC) is very common in developing countries. Retrospective data suggests that abiraterone acetate (AA) is active in patients that progressed to DES. This phase II study evaluated the efficacy and safety of abiraterone acetate in chemotherapy-naïve patients with metastatic CRPC who have progressed to DES. Methods: Patients with DES−refractory metastatic CRPC with ongoing ADT, serum testosterone level &lt; 50 ng/dL and ECOG of 0-2 were included. All patients received AA 1,000 mg with prednisone 5 mg once daily in a 28 days cycles. The primary endpoint was the time to PSA progression (PSAP) by PCWG2 and was previously reported. We present here secondary endpoints: overall survival, PSA response, maximum PSA change from baseline and safety. Results: A total of 46 patients were enrolled, median age was 69.8 years, 76% had gleason &gt; = 7 at diagnosis, median time from metastatic disease to DES discontinuation was 25.9 months, and a median duration of prior DES of 7.2 months. AA treatment resulted in median time to PSA progression of 7.3 months. PSA response rate (³ 50%) was 47.5% (95% CI: 36,1% to 68,5%) at 12 weeks and 57.5% (95% CI: 27.0% to 59.1%) at any time. 93.4% received chemotherapy after progression to AA. The median overall survival was 29.6 months. Substantial declines in serum androgens from baseline to week 12 occurred and in this group a higher proportion of PSA responses occurred. The incidence of adverse events (AEs) related to AA was 74% and prednisone 59%. Hypertension (21.7%), fatigue (19.6%) and oedema peripheral (13.0%) were the most frequent AA related AEs. The most frequent prednisone related AEs were hyperglycaemia (15.2%) hypertension (10.9%). Serious AEs occurred in 23.9% of subjects and 3 subjects (6.5%) died of AEs not related to study drugs. Conclusions: AA is well tolerated and demonstrated activity in mCRPC patients previously treated with DES, therefore it should be considered an option in chemo-naïve patients. Serum androgens levels tend to decrease with AA treatment and are associated with PSA responses. Clinical trial information: NCT02217566.

The efficacy and safety of abiraterone acetate in patients with high-risk prostate cancer: a meta-analysis based on six randomized control trials.

BackgroundAbiraterone acetate, a CYP17 enzyme inhibitor, can block the synthesis of androgens in the adrenal gland, prostate, and testis. The purpose of this study was to investigate the efficacy and safety of abiraterone acetate in high-risk prostate cancer patients, including metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC).MethodsA meta-analysis based on 6 randomized controlled trials (RCTs) was undertaken in compliance with the guidelines of systematic reviews and meta-analyses. Databases including PubMed, EMBASE, and Cochrane library were searched for relevant literature through to September 2019.ResultsThe pooled analysis reported abiraterone acetate showed significant efficacy in high-risk prostate cancer patients, including overall survival (OS) [HR 0.66, 95% confidence interval (CI), 0.61–0.73, P<0.001], the time to prostate-specific antigen (PSA) progression (HR 0.45, 95% CI, 0.34–0.59, P<0.001), progression-free survival (PFS) (according to radiographic evidence) (HR 0.55, 95% CI, 0.45–0.68, P<0.001) and PSA response rate (RR 2.49, 95% CI, 1.47–4.22, P<0.001). A subgroup analysis was carried out due to the significant heterogeneity between the studies. The incidence of arthralgia (RR 1.19), hypokalemia (RR 2.47), cardiac disorder (RR 1.48), and hypertension (RR 1.57) in the abiraterone acetate group was moderately higher than the control group.ConclusionsThe efficacy and safety of abiraterone acetate as an androgen receptor (AR) pathway targeted drug in high-risk prostate cancer patients was confirmed.

A tertiary care audit of using abiraterone acetate in patients of metastatic castrate-resistant prostate cancer.

Introduction:This is a retrospective analysis to assess the safety and efficacy of abiraterone acetate (AA) in metastatic castrate-resistant prostate cancer (mCRPC) patients treated at tertiary care institute.Materials and Methods:The clinical records of mCRPC patients treated with AA at our tertiary care institute between July 2013 and December 2015 were reviewed. The treatment efficacy, toxicities, and its determinants were analyzed.Results:A total of 59 mCRPC patients treated with AA were reviewed, of whom 37 were chemo-naive and 22 had received prior chemotherapy (postchemo). The median follow-up duration was 10.0/15.0 months for chemo-naïve/postchemotherapy patients. 43.2%/36.36% of chemo-naive/postchemo patients had visceral metastases. The median overall survival (OS) and progression-free survival (PFS) were 15/7.8 months and 10/5.3 months for chemo-naive/postchemo patients, respectively. Median time to best prostate-specific antigen response was 3.4 months. Abiraterone was relatively well tolerated with no grade 4 toxicity or treatment-related death. We found the presence of previous taxene use and baseline symptoms to be significantly determinant of OS with abiraterone.Conclusion:The present study reported the efficacy of abiraterone in both chemo-naïve and postchemo patients of mCRPC outside clinical trial setting. We found lower OS and PFS with abiraterone as compared to that reported in the clinical trial setting in both chemo-naïve and postchemo patients, and particularly in those patients with the visceral disease, and further clinical trial for abiraterone in this subgroup of patients is warranted.

Serum DHEA-S Is a Predictive Parameter of Abiraterone Acetate in Patients with Castration-resistant Prostate Cancer.

There is no definitive biomarker that predicts the effectiveness of abiraterone acetate. The objective of this study was to investigate whether dehydroepiandrosterone sulfate (DHEA-S) predicts the effectiveness of abiraterone acetate. This study included a total of 28 consecutive patients. The optimal cutoff value of DHEA-S for predicting the PSA response was calculated by receiver operating characteristic (ROC) analysis. The Cox proportional hazards model was performed to determine the predictive factors for the susceptibility to abiraterone acetate. Serum DHEA-S at baseline intercorrelated with the PSA response (correlation coefficient: -0.516). The optimal cutoff value of serum DHEA-S at baseline was 47.4 ug/dl in predicting >50% PSA decline. Serum PSA and serum DHEA-S at baseline were identified as significant factors for predicting PSA progression-free survival (p=0.010 and p=0.003, respectively). Serum DHEA-S at baseline may be a biomarker for predicting the prognosis of CRPC patients treated with abiraterone acetate.

Effectiveness, safety and cost of abiraterone acetate in patients with metastatic castration-resistant prostate cancer: a real-world data analysis.

New therapies with diverse mechanisms of action are available for metastatic castration-resistant prostate cancer (mCRPC). This study aims to evaluate the effectiveness, safety and cost of abiraterone acetate (AA) in patients with mCRPC. Observational retrospective cohort study in which mCRPC patients who initiated AA between January 1, 2012 and December 31, 2017, were included. The patients were followed-up until death or March 31, 2018. Demographic, clinical and economic data were collected from the corporate electronic information systems. Survival distributions were estimated using the Kaplan-Meier method and compared using the log-rank test. A total of 69 mCRPC patients were started on AA, of whom 18 (26.1%) received prior chemotherapy (post-CT) and 51 (73.9%) did not receive it (CT-naïve). A PSA decline of ≥ 50% was achieved in five (27.8%) post-CT and 32 (62.7%) CT-naïve patients (p = 0.011). Median time to PSA progression, progression-free survival (PFS) and overall survival (OS) were 4.4/7.9months (p = 0.003), 5.1/7.5months (p = 0.034) and 12.1/21.3months (p = 0.119), respectively, for post-CT/CT-naïve patients. Treatment-related adverse events (AEs) occurred in 10 (55.6%) post-CT and 11 (21.6%) CT-naïve patients (p = 0.007). The most common AEs were hypokalaemia (11.6%), hypertension (8.7%) and fatigue (5.8%). The cost per median PFS month and per median OS month was €2818.4/€2784.3 and €1187.9/€980.4 for post-CT/CT-naïve patients, respectively. CT-naïve patients treated with AA obtained a better clinical benefit in terms of effectiveness, safety and cost-effectiveness ratio than post-CT patients. The effectiveness outcomes were poorer than those reported previously in the clinical trial setting.

Prior switching to a second-line nonsteroidal antiandrogen does not impact the therapeutic efficacy of abiraterone acetate in patients with metastatic castration-resistant prostate cancer: a real-world retrospective study.

Even in the era of novel targeted agents, switching to a second-line nonsteroidal antiandrogen (NSAA) is still widely used in treating metastatic castration-resistant prostate cancer (mCRPC), especially in undeveloped countries. However, whether prior treatment with a second-line NSAA would impact the efficacy of abiraterone acetate (Abi) remains uncertain. In the current study, 87 mCRPC patients treated with Abi were analyzed. Among them, 21 were treated with a second-line NSAA (from bicalutamide to flutamide) before receiving abiraterone, while the remaining 66 received Abi directly. Therapeutic efficacy of Abi was compared between those with and without prior second-line NSAA using Kaplan–Meier curves, log-rank test, and Cox regression models. The therapeutic efficacy of Abi was similar between those with or without the prior switching treatment of flutamide, in terms of either prostate-specific antigen progression-free survival (PSA-PFS, 5.5 vs 5.6 months, P = 0.967), radiographic progression-free survival (rPFS, 12.8 vs 13.4 months, P = 0.508), overall survival (OS, not reached vs 30.6 months, P = 0.606), or PSA-response rate (71.4% [15/21] vs 60.6% [40/66], P = 0.370). This is the first time that the impact of prior switching of treatment to a second-line NSAA on the efficacy of Abi in mCRPC patients has been addressed. Our data support that, use of prior sequential bicalutamide and flutamide does not seem to preclude response to abiraterone, although larger cohort studies and, ideally, a randomized controlled trial are needed. These findings will facilitate doctors’ decision-making in the treatment of mCRPC patients, especially for those with previous experience of switching NSAA second-line treatments in the clinic.

Real-world safety profile of abiraterone acetate in patients with castration-resistant prostate cancer and cardiovascular comorbidities: a retrospective, single center study

Background: Abiraterone acetate became a referral treatment for metastatic castration-resistant prostate cancer (mCRPC) in a post-docetaxel setting despite a remarkable percentage of cardiovascular adverse events (AEs). As a consequence, the evaluation of cardiovascular safety in patients at risk should be mandatory. We aimed to assess the cardiovascular safety of abiraterone acetate in a real-world series of mCRPC patients treated at our institution.&#x0D; Materials and Methods: We retrospectively included mCRPC patients with at least 1 active cardiovascular comorbidity or risk factor according to the European Society of Cardiology (ESC) guidelines and who started treatment with abiraterone acetate from April 2011 to July 2012. Cardiac assessment with electrocardiogram and echocardiogram was performed at baseline and at treatment discontinuation. AEs were defined according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Statistical analyses were performed by descriptive statistics as appropriate.&#x0D; Results: We included 51 patients of whom 18% had an ESC score risk for a major cardiovascular event ≥4%. At a median follow-up of 36 months, no cardiac AEs (rhythm abnormalities or left ventricular function decrease) were observed. The most frequent grade 1-2 AE reported was fluid retention (18%) followed by hypertension and asthenia (16%). The most frequent grade 3-4 AEs were asthenia and pruritus/rash. No patients discontinued abiraterone because of toxicity.&#x0D; Conclusions: Abiraterone acetate showed a favorable safety profile in mCRPC patients with cardiovascular comorbidities or risk factors in a post-docetaxel setting, but further studies are needed to confirm our findings and to explore other settings of disease.

Randomized phase 2 therapeutic equivalence study of abiraterone acetate fine particle formulation vs. originator abiraterone acetate in patients with metastatic castration-resistant prostate cancer: The STAAR study

BackgroundThis multicenter, randomized, open-label, active-controlled study evaluated therapeutic equivalence, steady-state pharmacokinetics, and safety of a novel abiraterone acetate fine particle formulation (AAFP) 500mg plus methylprednisolone vs. the originator AA (OAA) 1000mg plus prednisone in men with metastatic castrate-resistant prostate cancer (mCRPC). The primary endpoint was a comparison of average of serum testosterone levels on treatment days 9 and 10 between groups. MethodsMen with progressive mCRPC, receiving gonadotropin-releasing hormone agonist or antagonist therapy, and with a serum testosterone level of <50ng/dl were randomized 1:1 to either AAFP 500mg daily plus 4mg methylprednisolone orally twice daily (BID), or OAA 1000mg daily plus 5mg prednisone BID for 84 days. Serum testosterone, serum prostate-specific antigen (PSA), steady-state (trough) abiraterone pharmacokinetics, and safety were evaluated. ResultsFifty-three patients were enrolled (n = 24, AAFP; n = 29, OAA). Mean age was 75.1 years and 54.7% had Gleason>7. Over 90% of patients in each group achieved absolute testosterone levels of ≤1ng/dl during the study. The averaged absolute testosterone levels ≤0.1ng/dl were achieved in 25% of AAFP-treated patients and 17% of OAA-treated patients. A PSA-50 response was observed in>65% of patients in both groups on days 28, 56, and 84 (P = NS, all timepoints). Days 9 and 10 averaged rounded-up least squares (LS) mean (SE) serum testosterone levels were comparable (1.05ng/dl [0.04], AAFP; 1.02ng/dl [0.03], OAA; P = 0.4703 for LS mean difference). The geometric mean ratio between groups was 1.021 (90% CI: 0.965–1.081); the 90% CI fell within 80.0% to 125.0% equivalence limits. The LS mean differences in abiraterone trough plasma concentrations were not statistically significant at any visit. Adverse event frequency was comparable between arms (75.0%, AAFP; 82.8%, OAA). Musculoskeletal events were more common among OAA-treated patients (37.9% vs. 12.5%). ConclusionTherapeutic equivalence between AAFP 500mg daily and OAA 1000mg daily based on serum testosterone levels was confirmed in mCRPC patients. Both agents led to similar PSA-50 response rates. Abiraterone trough levels were similar between treatments. No new safety concerns were observed.

Safety and Efficacy of Abiraterone Acetate in Patients (pts) aged 75 or more with Metastatic Castration Resistant Prostate Cancer (mCRPC) in Both Pre-chemotherapy and Post-chemotherapy Settings: The Real Life Experience of Our Institution

Safety and Efficacy of Abiraterone Acetate in Patients (pts) aged 75 or more with Metastatic Castration Resistant Prostate Cancer (mCRPC) in Both Pre-chemotherapy and Post-chemotherapy Settings: The Real Life Experience of Our Institution

1107TiP - Phase II trial of abiraterone acetate in patients with relapsed and/or metastatic, castration resistant AR expressing salivary glands carcinomas (SGCs)

1107TiP - Phase II trial of abiraterone acetate in patients with relapsed and/or metastatic, castration resistant AR expressing salivary glands carcinomas (SGCs)

The impact of statin use on the efficacy of abiraterone acetate in patients with castration-resistant prostate cancer.

Statins compete with DHEAS for influx through the SLCO2B1 transporter, which may prolong time to progression (TTP) on androgen deprivation therapy. Abiraterone acetate (AA) may also undergo SLCO-mediated transport. Based on preclinical findings showing antagonism, we hypothesized that statins may compete with AA for influx via SLCO2B1 and could negatively impact drug efficacy. We queried two institutional clinical databases (Dana-Farber Cancer Institute [DFCI], Johns Hopkins University [JHU]) for CRPC patients treated with AA. Treatment duration was a surrogate for TTP. Associations between statin use and AA duration were estimated using the Kaplan-Meier method. Multivariable Cox regression modeling adjusted for known prognostic factors. Of the 224 DFCI and 270 JHU patients included, the majority (96%) had metastatic disease. Nearly half (41% and 45%) were statin users. In the DFCI cohort, there was a trend toward longer AA duration in statin users: 14.2 versus 9.2 months (HR 0.79, 95%CI: 0.57-1.09, P = 0.14). There was no association between statin use and AA duration in the JHU cohort: 8.3 versus 8.0 months (HR 0.89, 95%CI: 0.69-1.16, P = 0.38) in the statin users versus non-users, except for a trend in patients that had not previously received docetaxel or enzalutamide (HR 0.79; 95%CI: 0.57-1.10). Contrary to our initial hypothesis, there was a trend toward longer (rather than shorter) AA duration in statin users in the entire DFCI cohort and in the enzalutamide- and docetaxel-naïve JHU patients. Together, these results do not support the hypothesis that statins interfere with AA efficacy.

Real-world treatment with abiraterone acetate in patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC).

239 Background: In the COU-AA-302 trial, abiraterone acetate plus prednisone (AAP) resulted in extension of radiographic progression-free survival (rPFS) and overall survival in chemotherapy-naïve mCRPC patients compared to prednisone alone. However, limited data on AAP treatment and outcomes is available in the real-world in this setting. The aim of this study is to describe the duration of AAP treatment in routine clinical practice in mCRPC patients prior to chemotherapy. Methods: The study was designed as a retrospective chart review of mCRPC patients identified through oncology and urology practice in Belgium, France, Germany and the UK. This first analysis reports baseline patient characteristics at AAP initiation for the first 224 patients. Treatment duration, PFS and rPFS were estimated using Kaplan-Meier curves. Potential factors associated with treatment duration were explored using the log-rank test. Results: Data from 224 mCRPC patients treated with AAP (Belgium: 67; Germany: 150; UK: 7; none from France) across 19 centres was considered in this initial analysis. At baseline, the median age was 75.5 years (interquartile range [IQR]: 69.0-82.0) and the median PSA level was 50.0 ng/mL (IQR: 21.0-121.0). Patients with visceral metastases (9.8%) and ECOG 2-3 (9.4%) were included in this study, in contrast to those included in the COU-AA-302 study. Median duration of AAP treatment was 11.6 months (95% confidence interval [CI]: 10.2-12.8), whilst median PFS and rPFS were 11.9 months (95% CI: 10.8-13.3) and 16.5 months (95% CI: 13.5-20.0), respectively. Reasons for discontinuing AAP involved PSA progression (52.2%), radiographic progression (38.9%), symptomatic progression (27.8%), non-toxic death (19.4%) and toxicity (2.2%). Treatment duration was significantly longer in mCRPC patients with either baseline ECOG status 0, lower PSA, alkaline phosphatase, aspartate aminotransferase, or lactate dehydrogenase levels (p &lt; 0.05). Conclusions: The results of this study suggest similar treatment duration and rPFS for mCRPC patients in this real-life cohort with poorer clinical features compared to those observed in the COU-AA-302 trial population.

718O - PTEN loss as a predictive biomarker for the Akt inhibitor ipatasertib combined with abiraterone acetate in patients with metastatic castration-resistant prostate cancer (mCRPC)

718O - PTEN loss as a predictive biomarker for the Akt inhibitor ipatasertib combined with abiraterone acetate in patients with metastatic castration-resistant prostate cancer (mCRPC)

Safety of long-term exposure to abiraterone acetate in patients with castration-resistant prostate cancer and concomitant cardiovascular risk factors

We aimed to evaluate the long-term safety profile of abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC) with controlled cardiovascular comorbidities or risk factors. We retrospectively analysed the clinical charts of consecutive mCRPC patients with cardiac disorders/risk factors who had been treated with abiraterone 1000 mg once daily plus prednisone 5 mg twice daily for a median duration of 16 months at an oncology referral centre between April 2011 and July 2015. Patients underwent an electrocardiogram (ECG) and echocardiographic assessments, including measurement of left ventricular ejection fraction (LVEF) at baseline and at the end of treatment. Blood pressure (BP) was measured daily at home. During follow up (median 24 months), all adverse events were recorded. Cardiac events (CEs) were defined, according to Common Terminology Criteria for Adverse Events version 4.0, as the appearance of a symptomatic CE that required medical intervention. A total of 51 patients (median age 71 years) were evaluated. Pre-existing cardiovascular conditions included hypertension (41%), cardiac ischaemia (12%), stroke (9%), dyslipidaemia (18%) and type 2 diabetes mellitus (12%). No CEs were recorded and no changes in LVEF were observed. The most frequently reported adverse events were Grade 1-2 fluid retention (18%), hypertension (16%) and asthenia (16%). No patients permanently discontinued abiraterone due to cardiac events. Long-term abiraterone treatment was well tolerated in mCRPC patients with controlled cardiovascular comorbidities/risk factors, with no apparent worsening of cardiovascular conditions from baseline over an extended observation period.

Common Genetic Variation in CYP17A1 and Response to Abiraterone Acetate in Patients with Metastatic Castration-Resistant Prostate Cancer.

Treatment with abiraterone acetate and prednisone (AA/P) prolongs survival in metastatic castration-resistant prostate cancer (mCRPC) patients. We evaluated the genetic variation in CYP17A1 as predictive of response to AA/P. A prospective collection of germline DNA prior to AA/P initiation and follow-up of a mCRPC cohort was performed. Five common single-nucleotide polymorphisms (SNPs) in CYP17A1 identified using a haplotype-based tagging algorithm were genotyped. Clinical outcomes included biochemical response and time to biochemical progression on AA/P. Logistic regression was used to assess the association between tag SNPs and biochemical response. Proportional hazards regression was used to assess the association between tag SNPs and time to biochemical progression. Odds or hazard ratio per minor allele were estimated and p-values below 0.05 were considered statistically significant. Germline DNA was successfully genotyped for four tag SNPs in 87 patients. The median age was 73 years (54–90); the median prostate-specific antigen was 66 ng/dL (0.1–99.9). A single SNP, rs2486758, was associated with lower odds of experiencing a biochemical response (Odds ratio 0.22, 95% confidence interval 0.07–0.63, p = 0.005) and a shorter time to biochemical progression (Hazard ratio 2.23, 95% confidence interval 1.39–3.56, p < 0.001). This tag SNP located in the promoter region of CYP17A1 will need further validation as a predictive biomarker for AA/P therapy.