Abiraterone in metastatic castration-resistant prostate cancer: Efficacy and safety in unselected patients

Real-world outcomes for first line next-generation hormonal agents in metastatic prostate cancer: a systematic review

Aim: This review aims to summarize published evidence on the real-world (RW) outcomes of abiraterone or enzalutamide in first-line metastatic castration-resistant prostate cancer. Materials & methods: Studies reporting on RW effectiveness, safety, economic and/or health-related quality of life outcomes were identified by systematic literature review (2011-2021, incl. Embase®, MEDLINE®) and presented in a qualitative synthesis. Risk of bias was assessed using ROBINS-I or the Molinier checklist. Results: 88 studies (n = 83,427 patients) were included. Median progression-free (40 studies) and overall survival (38 studies) ranged from 3.7 to 20.9 months and 9.8 to 45 months, respectively. Survival, safety and economic outcomes were similar across individual treatments, while limited health-related quality of life evidence suggested improvements with abiraterone. Risk of bias was moderate to high. Conclusion: RW outcomes in first-line metastatic castration-resistant prostate cancer remain poor despite treatment, highlighting an unmet need for new regimens. This review was supported by AstraZeneca and Merck Sharp & Dohme.

Real-life data of abiraterone acetate and enzalutamide treatment in post-chemotherapy metastatic castration-resistant prostate cancer in Poland

Background

Abiraterone acetate (ABI) and Enzalutamide (ENZA) are second-generation hormone drugs that show breakthrough activity in post-chemotherapy, metastatic castration-resistant prostate cancer (mCRPC). The leading oncological and urological guidelines indicate both drugs with the same strong recommendation. There is a lack of randomized trials which compare the efficacy of ABI and ENZA. The current study aimed to compare the effectiveness of the drugs with an analysis of prognostic factors related to those drugs.

Patients and methods

The study included 420 patients with docetaxel (DXL) pretreated mCRPC from seven Polish cancer centers. Patients were treated according to inclusion and exclusion criteria in the Polish national drug program (1000 mg ABI and 10 mg prednisone, n=76.2%; ENZA, 160 mg; n=23.8%). The study retrospectively analyzed the overall survival (OS), time to treatment failure (TTF), PSA 50% decline rate (PSA 50%) and selected clinic-pathological data.

Results

In the study group, the median OS was 17 months (95% CI: 15.6-18.3). The median OS (26.1 vs. 15.7 mo.; p<0.001), TTF (14.2 vs. 7.6 mo.; p<0.001) and PSA 50% (87.5 vs. 56%; p<0.001) were higher in ENZA than in ABI treatment. Multivariate analysis shows that ENZA treatment and PSA nadir <17.35 ng/mL during or after DXL treatment were related to longer TTF. ENZA treatment, DXL dose ≥750 mg, PSA nadir <17.35 ng/mL during or after DXL treatment was related to longer OS.

Conclusions

ENZA treatment may be related to more favorable oncological outcomes than ABI treatment in the studied Polish population of patients. A 50% decline in PSA is an indicator of longer TTF and OS. Due to the non-randomized and retrospective nature of the analysis, the current results require prospective validation.

Comparison of real-life data of abiraterone acetate and enzalutamide in metastatic castration-resistant prostate cancer

To compare enzalutamide (E) and abiraterone acetate (AA) in terms of efficacy, survival and to characterize prognostic factors affecting survival in metastatic castration-resistant prostate cancer (mCRPC) patients. A total of 250 patients treated with E or AA in 5 centers were included. The number of patients with no prostate specific antigen (PSA) decline was higher in the AA group than that in the E group, and the proportion of patients with a PSA decline of ≥ 50% was higher in the E group (p = 0.020). Radiological progression free survival (rPFS) and overall survival (OS) were significantly longer in the E group when compared to that in the AA group (p < 0.001 and p = 0.027, respectively). In the E group, rPFS was significantly longer than that in the AA group in both pre- and post-docetaxel settings (p = 0.010 and p = 0.003, respectively). OS was similar in the pre-docetaxel setting; but in the post-docetaxel setting, E group had a significantly longer OS than the AA group (p = 0.021). In the multivariate analysis performed in the whole patient group, we found that good prognostic factors for rPFS were E treatment, being ≥ 75 years and a PSA decline of ≥ 50% while there was no factor affecting OS. With longer OS and PFS, E seems to be more suitable for mCRPC patients in the post-docetaxel setting than AA.

Hospitalization for adverse events under abiraterone or enzalutamide exposure in real-world setting: A French population-based study on prostate cancer patients

AIMS

Safety profiles of abiraterone and enzalutamide rely mainly on Phase III clinical trials. Our objective was to estimate the incidence rate ratio (IRR) for certain adverse events leading in real life to hospitalization (atrial fibrillation, acute heart failure, ischaemic heart disease, acute kidney injury [AKI], ischaemic stroke, torsade de pointe/QT interval prolongation, hepatitis and seizure), comparing abiraterone to enzalutamide. We also set out to discuss previously identified safety signals.

METHOD

Using the French National Health Insurance System database, all patients newly exposed to abiraterone or enzalutamide between 2013 and 2017 and followed until 31 December 2018 were targeted. IRRs for each event were estimated using a Poisson model in a sub-population of patients without contraindications or precautions for use for either treatment.

RESULTS

Among 11 534 new users of abiraterone and enzalutamide, AKI (IRR 1.42, 95% CI: 1.01-2.00), liver monitoring suggestive of hepatic damage (IRR 3.06, 95% CI: 2.66-3.53) and atrial fibrillation (IRR 1.12, 95% CI: 1.05-1.19) were significantly more often observed with abiraterone than with enzalutamide.

CONCLUSION

Our study provides knowledge on abiraterone and enzalutamide real-life safety profiles, especially for events leading to hospitalization. Despite several limitations, including the lack of clinical data, the safety signal for AKI under abiraterone is in line with results of an analysis of the French pharmacovigilance database, which requires further specific investigations. Enlightening the clinicians' therapeutic choices for patients treated for prostate cancer, our study should lead to clinicians being cautious in the use of abiraterone.

Efficacy of abiraterone acetate in castration-resistant metastatic prostate cancer: A real-world data analysis

PURPOSE

The aim of this study was to evaluate the efficacy of abiraterone in patients with castration-resistant metastatic prostate cancer.

MATERIALS AND METHODS

We retrospectively analyzed 51 patients with mCRPC treated with abiraterone acetate from January 2014 to August 2018. Clinicopathological information, treatment modalities, treatment responses, and survival times were retrospectively reviewed.

RESULTS

A total of 51 patients who received abiraterone 1000 mg/day + prednisone 10 mg/day between January 2014 and August 2018 were included in the study. Of these patients, 33 (64.7%) had post-chemotherapy (CT) and 18 (35.3%) had CT-naive abiraterone receipt. Median overall survival (OS) was 17.3 months (range 9.3-33.1). Median OS was found to be 12.7 months (range 9.4-18.3) and 29.4 months (range 9.3-33.0) in the CT-naive and post-CT group, respectively (P = .236). Median radiographic PFS (rPFS) was 10.1 months (range 4.5-18.4). In the CT-naive group, rPFS was 10.1 months (IQR 6.0-14.7) and in the post-CT group, it was 9.7 months (range 4.0-18.4) (P = .808). PSA progression-free survival (PSA-PFS) was 9.1 months (range 4.6-13.1). In the CT-naive group, PSA-PFS was 7.4 months (range 4.6-13.4) and in post-CT, it was 9.1 months (range 4.8-13.1) (P = .843).

CONCLUSIONS

These results show that abiraterone acetate is an effective and reliable agent in real-life data.