Bone-Modifying Agents in Patients With High-Risk Metastatic Castration-Sensitive Prostate Cancer Treated With Abiraterone Acetate

Importance

The association between the use of bone-modifying agents (BMAs) and the outcomes among patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with abiraterone acetate plus prednisone (AAP) remains unclear.

Objective

To investigate the association between BMA use and the outcomes of patients with mCSPC receiving AAP.

Design, Setting, and Participants

In this cohort study, a post hoc analysis of individual participant data from the LATITUDE trial was performed. The LATITUDE trial, a phase 3 randomized clinical trial, aimed to assess the efficacy of AAP and androgen deprivation therapy (ADT) vs dual-placebo and ADT in patients with high-risk mCSPC (data cutoff, August 15, 2018). Eligible patients had newly diagnosed prostate cancer with metastases and at least 2 of 3 high-risk factors (Gleason score ≥8, presence of ≥3 lesions on bone scan, or presence of measurable visceral metastasis). The trial was conducted at 235 sites in 34 countries. Data for the present study were evaluated from July 18 to September 23, 2023.

Exposures

Use of BMAs was defined as the administration of bisphosphonates and denosumab within 90 days before and after randomization.

Main Outcomes and Measures

The primary outcomes were time to skeletal-related events (SREs) and overall survival (OS). An SRE was defined as a clinical or pathological fracture, spinal cord compression, palliative radiation to bone, or surgery involving bone. Differences in these outcomes were examined using the restricted mean survival time from inverse probability of treatment weighting-adjusted Kaplan-Meier curves, estimated until the last event was observed (longest time observed, 63.9 months). Treatment × covariate interactions were analyzed using weighted Cox proportional hazards regression models for the total cohort.

Results

In the total cohort of 1199 patients (956 [79.7%] younger than 75 years), 597 (49.8%) received AAP and ADT, including 474 (79.4%) younger than 75 years and 384 (64.3%) with more than 10 bone metastases (AAP cohort); 602 (50.2%) were treated with dual placebo and ADT, including 482 (80.1%) younger than 75 years and 377 (62.6%) with more than 10 bone metastases (ADT cohort). In the AAP cohort, 132 patients (22.1%) received BMAs, while in the ADT cohort, 131 (21.8%) did. Zoledronic acid was the most frequently administered BMA in both the AAP (93 [70.5%]) and the ADT (88 [67.2%]) cohorts. During the median follow-up of 51.8 (IQR, 47.2-57.0) months in the AAP cohort, BMA use was associated with a longer time to SRE (difference, 7.8 [95% CI, 4.2-11.3] months) but not with OS (difference, 1.6 [95% CI, -2.5 to 5.8] months). In the ADT cohort, BMA use was associated with both time to SRE (difference, 9.3 [95% CI, 5.2-13.3] months) and OS (difference, 5.5 [95% CI, 3.2-9.8] months). No evidence was found that the outcomes of BMA varied by AAP or ADT (hazard ratio for time to SRE, 0.99 [95% CI, 0.48-2.08]; P = .99 for interaction; hazard ratio for OS, 1.31 [95% CI, 0.88-1.96]; P = .18 for interaction).

Conclusions and Relevance

The findings of this cohort study suggest that use of BMAs was associated with a longer time to SRE in patients with high-risk mCSPC treated with ADT, with or without AAP, suggesting that BMA use might provide benefits to this population.

The impact of locoregional treatments for metastatic castration resistant prostate cancer on disease progression: real life experience from a multicenter cohort

BACKGROUND

Available data on medical treatment of metastatic castration resistant prostate cancer (mCRPC) support the use of more than one therapy line to delay chemotherapy. We evaluate in a longitudinal real life multicenter cohort, the oncological outcome of mCRPC patients treated with Abiraterone Acetate (AA) and Enzalutamide (EZ) in a chemo-naïve setting, who received locoregional treatments for subsequent development of oligorecurrent disease.

METHODS

We prospectively collected data on chemo-naïve mCRPC patients, who received either AA or EZ as first or second line treatment between Oct-2012 and Nov-2020 at 5 centers. High-volume disease at mCRPC onset was defined as bulky positive nodes (≥5 cm) or more than 6 bone metastases. Survival probabilities were computed at 12, 24, 48 and 60 months after treatment start. The impact of loco-regional treatments on progression free survival (PFS) were assessed with the Kaplan-Meier method and the log-rank test was applied.

RESULTS

Overall, 117 chemo-naive mCRPC patients received a first line therapy. Fifty-seven (48.7%) patients received AA and 60 (51.3%) received EZ. Eight (6.7%) patients underwent salvage chemotherapy after first line failure. Overall, 28 patients shifted to a second line therapy. Two-yr progression-free, cancer-specific and overall survival probabilities were 65.5%, 82.2% and 78.4% respectively. Since diagnosis of mCRPC, oligo progression occurred in 25 patients who received stereotactic radiation therapy (23/25, 92%) focused on metastasis (4 nodal sites and 19 bones) or salvage lymph node dissection (2/25, 8%). At Kaplan-Meier analysis, patients with low volume disease displayed higher PFS probabilities (log rank p = 0.009) and in this subgroup of patients loco-regional treatments had a significant impact on PFS (p = 0.048), while it was negligible in the whole cohort and in patients with high volume disease (p = 0.6 and p = 0.75).

CONCLUSIONS

Low-volume mCRPC patients are exposed to improved PFS and seem to benefit from locoregional treatments.

Effect of Concomitant Medications on Treatment Response and Survival in De Novo Metastatic Prostate Cancer: Secondary Analysis of the LATITUDE Study

PURPOSE

It is unclear whether exposure to commonly prescribed medications influences survival and treatment response in patients with de novo high-risk metastatic prostate cancer (mPCa) treated with androgen receptor pathway inhibitors (ARPIs).

METHODS

We performed a secondary analysis of the LATITUDE trial to determine whether receipt of concomitant medications influenced the effect of abiraterone acetate and prednisone, in addition to androgen deprivation therapy (ADT), on overall survival (OS) and prostate cancer-specific mortality (PCSM) in patients with de novo mPCa. We focused on 7 commonly prescribed classes of medications: metformin, statins, proton pump inhibitors (PPIs), cyclooxygenase 2 (COX-2) inhibitors, aspirin, acetaminophen, and NSAIDs (nonselective COX inhibitors). To account for multiple testing, a two-sided p < 0.0024 was set as the threshold for statistical significance.

RESULTS

Overall, 1135 patients were eligible. There was some evidence of a differential treatment effect from abiraterone among patients who received concomitant NSAIDs (hazard ratio [HR] for OS: 0.54; 95% CI: 0.42-0.70) versus those who did not (HR: 0.74; 95% CI: 0.60-0.91), though this did not reach significance (interaction p = 0.05). A similar non-significant finding of heterogeneity of effect from abiraterone was noted among patients who received concomitant aspirin (HR for OS: 0.93 [0.63-1.36]) versus those who did not (HR: 0.61 [0.51-0.73]) (interaction p = 0.04). Receipt of NSAIDs was independently associated with a significantly inferior OS (HR: 1.37 [1.15-1.62]; p < 0.001) and higher relative incidence of PCSM (sHR: 1.47 [1.21-1.78]; p < 0.001).

CONCLUSIONS

This exploratory analysis did not find statistically significant evidence of differences in treatment effects from ADT plus abiraterone in de novo high-risk mPCa based on the receipt of concurrent medications. The receipt of NSAIDs was independently associated with increased PCSM and inferior OS.

FDA Approval Summary: Olaparib in Combination With Abiraterone for Treatment of Patients With BRCA-Mutated Metastatic Castration-Resistant Prostate Cancer

PURPOSE

This article summarizes the US Food and Drug Administration (FDA) review of the data leading to approval of olaparib plus abiraterone for the treatment of patients with deleterious or suspected deleterious BRCA-mutated (BRCAm) metastatic castration-resistant prostate cancer (mCRPC), as determined by an FDA-approved companion diagnostic test.

PATIENTS AND METHODS

Approval was based on the results from PROpel, a double-blind trial that randomly assigned 796 patients with mCRPC to abiraterone plus prednisone or prednisolone with either olaparib or placebo. The primary end point was radiographic progression-free survival (rPFS) per investigator assessment.

RESULTS

There was a statistically significant improvement in rPFS for olaparib plus abiraterone versus placebo plus abiraterone, with a median rPFS of 25 versus 17 months and a hazard ratio (HR) of 0.66 (95% CI, 0.54 to 0.81) in the intention-to-treat population. In an exploratory analysis of the subgroup of 85 patients with BRCAm mCRPC, the HR for rPFS was 0.24 (95% CI, 0.12 to 0.45) and the HR for overall survival (OS) was 0.30 (95% CI, 0.15 to 0.59). In an exploratory analysis of the subgroup of 711 patients without an identified BRCA mutation, the HR for rPFS was 0.77 (95% CI, 0.63 to 0.96) and the HR for OS was 0.92 (95% CI, 0.74 to 1.14). Adding olaparib to abiraterone resulted in increased toxicity, including anemia requiring transfusion in 18% of patients.

CONCLUSION

In patients with mCRPC, efficacy of the combination of olaparib plus abiraterone was primarily attributed to the treatment effect in the BRCAm subgroup, the indicated population for the approval. For patients without BRCAm, the FDA determined that the modest rPFS improvement, combined with clinically significant toxicities, did not demonstrate a favorable risk/benefit assessment.

Effect of BMI and hemoglobin A1c on survival of veterans with metastatic castration-resistant prostate cancer treated with abiraterone or enzalutamide

BACKGROUND

Abiraterone acetate and enzalutamide are two common therapies for metastatic castration-resistant prostate cancer (mCRPC) that have shown improved overall survival (OS). The drugs have different mechanisms of action with limited comparative trials to evaluate treatment in patients with comorbidities such as obesity and diabetes. This is important since abiraterone requires the co-administration of prednisone. We assessed the relationship between body mass index (BMI), hemoglobin A1c (HbA1c), treatment, and survival in mCRPC.

METHODS

Veterans treated with abiraterone or enzalutamide within the Veterans Health Administration between September 10, 2014 and June 2, 2017 with BMI and HbA1c were identified. Additional variables included age, baseline prostate-specific antigen at first treatment for mCRPC, race, and the Charlson comorbidity index. Differences in survival were compared using the Kaplan-Meier method. Cox proportional hazards regression modeling was used to assess the association between initial treatment, BMI, and HbA1c while adjusting for confounding variables.

RESULTS

A total of 5231 patients were identified with a mean age of 75.2 years and 1241 (23.7%) were of black race. BMI was associated with OS with longest median survival of 29.8 months in BMI ≥ 30 (n = 1903), 23.9 months in BMI 25-30 (n = 1879), 15.9 months in BMI 18.5-25 (n = 1336), and 9.2 months in BMI < 18.5 (n = 113, p < 0.001). In a multivariable model compared to normal BMI, increased mortality was observed in BMI < 18.5 (adjusted hazard ratio (aHR) = 1.583, 95% confidence interval [CI]: 1.29-1.94) and a decreased mortality in BMI 25-30 (aHR = 0.751, 95% CI: 0.69-0.81) and BMI > 30 (aHR = 0.644, 95% CI: 0.59-0.70). In 3761 patients with BMI > 25, there was longer OS in patients treated with enzalutamide (28.4 months, n = 1615) compared to abiraterone (25.8 months, n = 2146, p = 0.002). In 1470 patients with BMI < 25, there was no difference in OS between patients treated with enzalutamide (16.0 months, n = 597, p = 0.513) or abiraterone (16.1 months, n = 873). In 1333 veterans with HbA1c ≥ 6.5%, initial prescription of enzalutamide was associated with longer OS compared with abiraterone (24.4 vs. 20.5 months, p = 0.0005). In 2088 patients with HbA1c < 6.5%, there was no difference in OS in patients who were initially prescribed enzalutamide versus abiraterone (25.7 vs. 23.5 months, p = 0.334).

CONCLUSIONS

In veterans with mCRPC, increased BMI was associated with longer survival. Veterans with BMI > 25 had longer survival with enzalutamide compared to abiraterone. In patients with HbA1c ≥ 6.5%, enzalutamide was associated with longer survival compared to abiraterone. These results may facilitate prognostication of survival and improve treatment selection based on patient comorbidities.

Predictive significance of inflammatory markers and mGPS in metastatic castration-resistant prostate cancer treated with abiraterone or enzalutamide

BACKGROUND

Prostate cancer is a prevalent cancer in men worldwide, and castration-resistant prostate cancer (CRPC) is characterized by disease progression despite androgen deprivation therapy. While clinical and prognostic biomarkers have been identified in CRPC, the significance of serum inflammatory markers remains unclear.

MATERIALS AND METHODS

This retrospective study included 79 CRPC patients treated with abiraterone or enzalutamide. Inflammatory markers, including the modified Glasgow prognostic score (mGPS), systemic immune-inflammation index (SII), and neutrophil-to-lymphocyte ratio (NLR), were assessed as predictive tools for treatment response. Patient data were obtained from medical charts, and statistical analyses were performed.

RESULTS

The median age of the patients was 67 years, with most having a Gleason score of 8-10. The median values for NLR, PLR, and SII were 2.9, 168.5, and 713.5, respectively. The objective response rate (ORR) to abiraterone or enzalutamide therapy was 55.1%. mGPS showed a significant association with ORR, with the mGPS 0 group having the highest response rate (59.5%). Median progression-free survival (PFS) was 12.8 months, and median overall survival (OS) was 35.4 months. Palliative radiotherapy during therapy and PSA doubling time were independent prognostic factors for PFS.

CONCLUSIONS

mGPS and PSA doubling time significantly impacted survival, and mGPS significantly predicted the treatment response in mCRPC, which may lead to further prospective studies.

Stereotactic Body Radiation Therapy and Abiraterone Acetate for Patients Affected by Oligometastatic Castrate-Resistant Prostate Cancer: A Randomized Phase II Trial (ARTO)

PURPOSE

ARTO (ClinicalTrials.gov identifier: NCT03449719) is a multicenter, phase II randomized clinical trial testing the benefit of adding stereotactic body radiation therapy (SBRT) to abiraterone acetate and prednisone (AAP) in patients with oligometastatic castrate-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

All patients were affected by oligometastatic CRPC as defined as three or less nonvisceral metastatic lesions. Patients were randomly assigned 1:1 to receive either AAP alone (control arm) or AAP with concomitant SBRT to all the sites of disease (experimental arm). Primary end point was the rate of biochemical response (BR), defined as a prostate-specific antigen (PSA) decrease ≥50% from baseline measured at 6 months from treatment start. Complete BR (CBR), defined as PSA < 0.2 ng/mL at 6 months from treatment, and progression-free survival (PFS) were secondary end points.

RESULTS

One hundred and fifty-seven patients were enrolled between January 2019 and September 2022. BR was detected in 79.6% of patients (92% v 68.3% in the experimental v control arm, respectively), with an odds ratio (OR) of 5.34 (95% CI, 2.05 to 13.88; P = .001) in favor of the experimental arm. CBR was detected in 38.8% of patients (56% v 23.2% in the experimental v control arm, respectively), with an OR of 4.22 (95% CI, 2.12 to 8.38; P < .001). SBRT yielded a significant PFS improvement, with a hazard ratio for progression of 0.35 (95% CI, 0.21 to 0.57; P < .001) in the experimental versus control arm.

CONCLUSION

The trial reached its primary end point of biochemical control and PFS, suggesting a clinical advantage for SBRT in addition to first-line AAP treatment in patients with metastatic castration-resistant prostate cancer.

Survival of veterans treated with enzalutamide and abiraterone for metastatic castrate resistant prostate cancer based on comorbid diseases

BACKGROUND

Comorbid diseases influence patient outcomes, yet little is known about how comorbidities interact with treatments for metastatic castrate-resistant prostate cancer (mCRPC). No head-to-head trials have compared the efficacy of abiraterone and enzalutamide - oral androgen-receptor targeted agents (ARTAs) for mCRPC. In patients with comorbid disease, outcomes with ARTAs may differ due to disparate mechanisms of action, adverse events, and drug interactions.

METHODS

Retrospective observational study of US veterans initiating treatment for mCRPC with abiraterone or enzalutamide between September 2014 and June 2017. Treatment duration and overall survival (OS) was compared based on age and comorbid diseases. The association between ARTA and OS was assessed using Cox proportional hazards and propensity-score matched modeling while adjusting for potential confounders. Sensitivity analyses were performed based on patient age, comorbidities, and subsequent treatments for mCRPC.

RESULTS

Of 5822 veterans treated for mCRPC, 43.0% initially received enzalutamide and 57.0% abiraterone. Veterans initially treated with enzalutamide versus abiraterone were older (mean 75.8 vs. 75.0 years) with higher mean Charlson comorbidity index (4.4 vs. 4.1), and higher rates of cardiovascular disease or diabetes (74.2% vs. 70.6%). In the entire population, veterans initially treated with enzalutamide had longer median OS compared to those initially treated with abiraterone (24.2 vs. 22.1 months, p = 0.001). In veterans with cardiovascular disease or diabetes, median treatment duration with enzalutamide was longer (11.4 vs. 8.6 months, p < 0.001) with longer median OS compared to abiraterone (23.2 vs. 20.5 months, p < 0.001). In a propensity score matched cohort, enzalutamide was associated with decreased mortality compared to abiraterone (HR 0.90, 95% CI 0.84-0.96).

CONCLUSIONS

Veterans with cardiovascular disease or diabetes had longer treatment duration and OS with enzalutamide compared to abiraterone. Further study of ARTA selection may benefit men with metastatic castrate resistant prostate cancer and likely hormone sensitive prostate cancer, especially among patients with comorbid diseases.

Cortisol as Biomarker for CYP17-Inhibition is Associated with Therapy Outcome of Abiraterone Acetate

BACKGROUND

Abiraterone acetate is an irreversible 17α-hydroxylase/C17, 20-lyase (CYP17) inhibitor approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients. Inhibition of this enzyme leads to low testosterone and cortisol levels in blood. There is growing evidence that clinical efficacy of abiraterone is related to the rate of suppression of serum testosterone. However, quantification of very low levels of circulating testosterone is challenging. We therefore aimed to investigate whether circulating cortisol levels could be used as a surrogate biomarker for CYP17 inhibition in patients with mCRPC treated with abiraterone acetate.

PATIENTS AND METHODS

mCRPC patients treated with abiraterone acetate were included. Abiraterone and cortisol levels were measured with a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS). On treatment cortisol and abiraterone concentrations were related to treatment response and progression free survival.

RESULTS

In total 117 patients were included with a median cortisol concentration of 1.13 ng/ml (range: 0.03 - 82.2) and median abiraterone trough concentration (Cmin) of 10.2 ng/ml (range: 0.58 - 92.1). In the survival analyses, abiraterone Cmin ≥ 8.4 ng/mL and cortisol  < 2.24 ng/mL were associated with a longer prostate-specific antigen (PSA) independent progression-free survival than patients with an abiraterone concentration  ≥ 8.4 ng/mL and a cortisol concentration ≥ 2.24 ng/mL (13.8 months vs. 3.7 months).

CONCLUSION

Our study shows that cortisol is not an independent predictor of abiraterone response in patients with mCRPC, but it is of added value in combination with abiraterone levels, to predict a response on abiraterone.

Randomized Phase II Multicenter Trial of Abiraterone Acetate With or Without Cabazitaxel in the Treatment of Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Improving clinical outcomes with novel drug combinations to treat metastatic castration-resistant prostate cancer (mCRPC) is challenging. Preclinical studies showed cabazitaxel had superior antitumor efficacy compared with docetaxel. Gene expression profiling revealed divergent effects of these taxanes in cycling cells. mCRPC are RB deficient rendering them hypersensitive to taxanes. These data suggested that upfront treatment with cabazitaxel with abiraterone may affect therapeutic response. We designed a phase II randomized noncomparative trial of abiraterone acetate/prednisone (AAP) or AAP and cabazitaxel (AAP + C) in men with mCRPC to address this hypothesis.

METHODS

This trial of 81 men with mCRPC determined the radiographic progression-free survival (rPFS), prostate-specific antigen (PSA) progression-free survival, overall objective response, and safety of AAP or AAP + C. Equally allocated patients received AAP followed by switching to cabazitaxel upon radiographic progression (arm 1) or upfront with AAP + C (arm 2). Patients were stratified into high-/low-risk groups by the Halabi nomogram. Real-time assessment of RB status and circulating tumor cell (CTC) analysis to correlate with clinical outcomes was exploratory.

RESULTS

Both treatment arms were well-tolerated. Median rPFS in AAP was 6.4 months (95% CI, 3.8 to 10.6) and median overall survival (OS) 18.3 months (95% CI, 14.4 to 37.6), respectively. Fifty-six percent of patients showed ≥50% decline in PSA. Median rPFS in AAP + C was 14.8 months (95% CI, 10.6 to 16.4), and median OS 24.5 months (95% CI, 20.4 to 35.0). There was a ≥50% decline in PSA in 92.1% of men. Neither RB expression in pretherapy tumor biopsy, CTC, or tissue explants identified those who may benefit from AAP + C.

CONCLUSION

AAP + C was safe with improved rPFS, OS duration, and a higher proportion of PSA declines. This suggests that AAP + C given earlier rather than sequentially may benefit some men. Further work is needed to identify this population.

Cost-effectiveness analysis of 7 treatments in metastatic hormone-sensitive prostate cancer: a public-payer perspective

BACKGROUND

Recently, several new treatment regimens have been approved for treating metastatic hormone-sensitive prostate cancer, building on androgen deprivation therapy alone. These include docetaxel androgen deprivation therapy, abiraterone acetate-prednisone androgen deprivation therapy, apalutamide androgen deprivation therapy, enzalutamide androgen deprivation therapy, darolutamide-docetaxel androgen deprivation therapy, and abiraterone-prednisone androgen deprivation therapy with docetaxel. There are no validated predictive biomarkers for choosing a specific regimen. The goal of this study was to conduct a health economic outcome evaluation to determine the optimal treatment from the US public sector (Veterans Affairs).

METHODS

We developed a partitioned survival model in which metastatic hormone-sensitive prostate cancer patients transitioned between 3 health states (progression free, progressive disease to castrate resistance state, and death) at monthly intervals based on Weibull survival model estimated from published Kaplan-Meier curves using a Bayesian network meta-analysis of 7 clinical trials (7208 patients). The effectiveness outcome in our model was quality-adjusted life-years (QALYs). Cost input parameters included initial and subsequent treatment costs and costs for terminal care and for managing grade 3 or higher drug-related adverse events and were obtained from the Federal Supply Schedule and published literature.

RESULTS

Average 10-year costs ranged from $34 349 (androgen deprivation therapy) to $658 928 (darolutamide-docetaxel androgen deprivation therapy) and mean QALYs ranged from 3.25 (androgen deprivation therapy) to 4.57 (enzalutamide androgen deprivation therapy). Treatment strategies docetaxel androgen deprivation therapy, enzalutamide androgen deprivation therapy docetaxel, apalutamide androgen deprivation therapy, and darolutamide-docetaxel androgen deprivation therapy were eliminated because of dominance (ie, they were more costly and less effective than other strategies). Of the remaining strategies, abiraterone acetate-prednisone androgen deprivation therapy was the most cost-effective strategy at a willingness-to-pay threshold of $100 000/QALY (incremental cost-effectiveness ratios = $21 247/QALY).

CONCLUSIONS

Our simulation model found abiraterone acetate-prednisone androgen deprivation therapy to be an optimal first-line treatment for metastatic hormone-sensitive prostate cancer from a public (Veterans Affairs) payer perspective.

Causal inferences and real-world evidence: A comparative effectiveness evaluation of abiraterone acetate against enzalutamide

Regulatory authorities are recognizing the need for real-world evidence (RWE) as a complement to randomized controlled trials in the approval of drugs. However, RWE needs to be fit for regulatory purposes. There is an ongoing discussion regarding whether pre-publication of a protocol on appropriate repositories, e.g. ClinicalTrials.gov, would increase the quality of RWE or not. This paper illustrates that an observational study based on a pre-published protocol can entail the same level of detail as a protocol for a randomized experiment. The strategy is exemplified by designing a comparative effectiveness evaluation of abiraterone acetate against enzalutamide in clinical practice. These two cancer drugs are prescribed to patients with advanced prostate cancer. Two complementary designs, including pre-analysis plans, were published before data on outcomes and proxy-outcomes were obtained. The underlying assumptions are assessed and both analyses show an increased mortality risk from being prescribed abiraterone acetate compared to enzalutamide.

Real-world survival outcome comparing abiraterone acetate plus prednisone and enzalutamide for nonmetastatic castration-resistant prostate cancer

BACKGROUND

There is little evidence of abiraterone acetate (AA) plus prednisone for patients with non-metastatic castration-resistant prostate cancer (nmCRPC). In this study, we conducted a comparative analysis of real-world survival outcomes between AA plus prednisone and enzalutamide (Enz) in patients with nmCRPC, utilizing our consortium dataset.

MATERIALS AND METHODS

The clinical records of 133 nmCRPC patients treated with first-line Enz or AA plus prednisone were analyzed. The primary endpoints of the study were overall survival (OS) and cancer-specific survival (CSS). Cumulative incidence function (CIF) using Fine and Gray models was also utilized to assess non-cancer-caused death considering the competing risk of cancer-caused death.

RESULTS

During a median follow-up of 36 months, 34 patients (25.6%) had deceased, with a median OS of 99 months in the entire cohort. There were no significant differences in comorbidities between the Enz and AA groups. Time to PSA progression (TTPP: HR 0.81, 95% CI 0.51-1.30, P = 0.375) and CSS (HR 1.32, 95% CI 0.55-3.44, P = 0.5141) were comparable between the two groups. However, intriguingly, there was a trend towards shorter OS in patients treated with AA plus prednisone compared to Enz (HR 0.57, 95% CI 0.29-1.12, P = 0.0978, median of 99 and 69 months in Enz and AA groups, respectively). CIF analysis revealed that nmCRPC patients treated with AA plus prednisone were more likely to result in non-cancer-caused death than those treated with Enz (HR 5.22, 95% CI 1.88-14.50, P = 0.0014).

CONCLUSIONS

Our real-world survival analysis suggests that while AA plus prednisone may demonstrate comparable treatment efficacy to Enz in the context of nmCRPC, there may be an increased risk of non-cancer-caused death. Physicians should take into consideration this information when making treatment decisions for patients with nmCRPC.

Real-World Treatment Patterns Among French Patients With Metastatic Castration-Resistant Prostate Cancer Under Abiraterone or Enzalutamide

PURPOSE

Using large French retrospective study cohort of chemotherapy-naïve metastatic castration-resistant prostate cancer patients (mCRPC; n = 10,308) comparing survival between patients who initiated abiraterone (ABI; 64%) and those initiating enzalutamide (ENZ; 36%), the present objective was to describe treatment patterns in the 2 years following initiation.

METHOD

Using the national health data system (SNDS) from 2014 to 2018, we first explored the number of treatment lines, and secondly, patterns of patient management using state sequence analysis; cluster analyses were performed on the 0 to 12 month and 13 to 24 month periods. Age, Charlson score, and duration of androgen deprivation therapy (ADT) were obtained for each cluster in the first year of follow-up.

RESULTS

Patients with only 1 treatment line accounted for 52%. In the 0 to 12 month sequence analysis, the main clusters among ABI/ENZ new users involved patients who continued the initial treatment (54% of 65% respectively) and discontinued active treatment (14.5% for both). Less than 2 years exposure to ADT prior to ABI/ENZ initiation was frequently observed for noncontrolled mCRPC, as shown in the death and switch from ABI/ENZ to docetaxel clusters. The clusters for a switch ABI/ENZ to ENZ/ABI involved 6% to 11% of the patients.

CONCLUSION

Our study suggested fairly similar patterns between ABI and ENZ initiation. The cluster of patients with active treatment discontinuation needs to be further investigated, as well as factors influencing therapeutic choice. Better understanding for the use of second-generation hormone therapy in mCRPC in real life, could improve its implementation by clinicians in the early stages of prostate cancer.

Second generation anti-androgens and androgen deprivation therapy with radiation therapy in the definitive management of high-risk prostate cancer

BACKGROUND

Evolving data suggest that men with high-risk localized prostate cancer may benefit from more potent androgen receptor inhibition in the context of curative intent radiotherapy. Recently updated American Society for Clinical Oncology (ASCO) evidence-based guidelines and the National Comprehensive Cancer Network (NCCN) Guidelines have updated recommendations for the consideration of adding second generation anti-androgens to androgen deprivation therapy (ADT) in men receiving radiation therapy (RT) for noncastrate locally advanced high and very high risk nonmetastatic or node positive prostate cancer.

METHODS AND RESULTS

We conducted a comprehensive review of existing published and abstract presented evidence behind RT with ADT for the definitive management of high-risk prostate cancer, particularly focused on the current phase II and III trial evidence for the addition of second generation anti-androgens to ADT in definitive RT treatment of high-risk prostate cancer and specifically focused on the recent STAMPEDE trial results with abiraterone acetate. We review the biological mechanisms in which second generation anti-androgens may help mitigate ADT resistance and provide radiosensitization through inhibition of DNA repair. Finally, we discuss ongoing clinical trials of potent androgen receptor (AR) inhibitors with ADT in this non-metastatic high-risk radiotherapy setting that may inform on future treatment guidelines.

CONCLUSIONS

Recent data suggest an overall survival benefit as well as increased probabilities of disease free and metastasis free survival in men with high and very high-risk localized, node positive, and oligometastatic hormone sensitive prostate cancer with abiraterone acetate and prednisone and support the use of potent AR inhibitors in this setting after informed decision making.

Plasma progastrin-releasing peptide level shows different predictive profiles for treatment response by androgen receptor axis-targeted agents in patients with metastatic castration-resistant prostate cancer

BACKGROUND

The neuroendocrine (NE) pathway cannot be ignored as a mechanism for castration-resistant prostate cancer (CRPC) progression. The neuromediator, gastrin-releasing peptide (GRP) may be involved in the aberrant activation of the normal androgen receptor (AR) and increased AR variants. This study focused on plasma levels of progastrin-releasing peptide (ProGRP) and examined the treatment outcomes with androgen receptor axis-targeted (ARAT) agents.

METHODS

One hundred patients with metastatic CRPC were enrolled. Enzalutamide (ENZ) or abiraterone acetate/prednisone (AA/P) were administered to 50 patients each in a nonrandomized manner as a first-line or later choice. Plasma ProGRP levels were determined using a chemiluminescent enzyme immunoassay, and data were collected prospectively. The study endpoints were prostate-specific antigen (PSA) response and survival estimates.

RESULTS

In the ENZ series, ProGRP levels correlated with the maximum PSA change from baseline (high ProGRP: -34.5% vs. low ProGRP: -85.7% p = .033). PSA progression-free survival (PFS), radiographic/symptomatic (r/s) PFS, and overall survival (OS) in patients with high ProGRP were significantly worse than those in patients with low ProGRP (median PSA-PFS: 3.3 vs. 10.0 months, p = .001, r/s PFS: 5.0 vs. 15.0 months, p < 0.001, and OS 17.5 vs. 49.0 months, p < .001, respectively). In addition, ProGRP showed an independent predictive value for all survival estimates in multivariate analyses. In the AA/P series, ProGRP levels did not correlate with the PSA change or predict PSA-PFS and r/s PFS, but they maintained a significant difference in OS (19.0 vs. 48.0 months, p = .003).

CONCLUSIONS

Plasma ProGRP provides a consistent predictive value for OS in metastatic CRPC patients who underwent therapy with ARAT agents. Meanwhile, ProGRP showed different predictive profiles for PSA- and r/s PFS between ENZ and AA/P. These findings clinically suggest a mechanism for CRPC progression involving the NE pathway via the GRP. The underlying mechanism of different predictive profiles by the ARAT agent should be explored in future research.

Body composition parameters were associated with response to abiraterone acetate and prognosis in patients with metastatic castration-resistant prostate cancer

OBJECTIVE

To investigate the predictive value of body composition parameters for biochemical response to abiraterone acetate (AA) in metastatic castration-resistant prostate cancer (mCRPC) patients with prior chemohormonal therapy.

METHODS

We retrospectively evaluated the clinicopathologic information of 132 mCRPC cases receiving AA treatment after chemohormonal therapy at hormone-sensitive stage from July 2018 to June 2021. All patients were divided into AA responders and non-responders according to the biochemical response to AA (prostate-specific antigen (PSA) reduction ≥50% than pretreatment). Multivariate Logistic analysis was used to determine the independent predictors and develop predictive model of biochemical response to AA. Cox regression analysis was utilized to investigate the prognostic factors for time to biochemical progression (TTBP), radiological progression-free survival (rPFS), failure-free survival (FFS), and overall survival (OS) after AA treatment.

RESULTS

There were 57 AA responders and 75 AA non-responders. Periprostatic fat area/prostate area (PPFA/PA) was decreased and skeletal muscle index (SMI) was increased in AA responders compared with AA non-responders. Multivariable logistic analysis demonstrated that ADT duration ≥12 months, bone metastasis only, high SMI and low PPFA/PA were independent predictors of biochemical response to AA treatment. The FFS, TTBP, rPFS, and OS of patients with lower SMI or higher PPFA/PA was decreased compared with that of patients with higher SMI or lower PPFA/PA, respectively. Combining SMI, PPFA/PA, ADT duration and metastatic sites performed well in differentiating AA responders from non-responders.

CONCLUSIONS

High SMI and low PPFA/PA could predict biochemical response to AA treatment and preferable prognosis in mCRPC patients with prior chemohormonal therapy at hormone-sensitive stage.

Clinical impact of volume of disease and time of metastatic disease presentation on patients receiving enzalutamide or abiraterone acetate plus prednisone as first-line therapy for metastatic castration-resistant prostate cancer

BACKGROUND

Metastatic castration-resistant prostate cancer remains a challenging condition to treat. Among the available therapeutic options, the androgen receptor signaling inhibitors abiraterone acetate plus prednisone (AA) and enzalutamide (Enza), are currently the most used first-line therapies in clinical practice. However, validated clinical indicators of prognosis in this setting are still lacking. In this study, we aimed to evaluate a prognostic model based on the time of metastatic disease presentation (after prior local therapy [PLT] or de-novo [DN]) and disease burden (low volume [LV] or high-volume [HV]) at AA/Enza onset for mCRPC patients receiving either AA or Enza as first-line.

METHODS

A cohort of consecutive patients who started AA or Enza as first-line treatment for mCRPC between January 1st, 2015, and April 1st, 2019 was identified from the clinical and electronic registries of the 9 American and European participating centers. Patients were classified into 4 cohorts by the time of metastatic disease presentation (PLT or DN) and volume of disease (LV or HV; per the E3805 trial, HV was defined as the presence of visceral metastases and/or at least 4 bone metastases of which at least 1 out the axial/pelvic skeleton) at AA/Enza onset. The endpoint was overall survival defined as the time from AA or Enza initiation, respectively, to death from any cause or censored at the last follow-up visit, whichever occurred first.

RESULTS

Of the 417 eligible patients identified, 157 (37.6%) had LV/PLT, 87 (20.9%) LV/DN, 64 (15.3%) HV/PLT, and 109 (26.1%) HV/DN. LV cohorts showed improved median overall survival (59.0 months; 95% CI, 51.0-66.9 months) vs. HV cohorts (27.5 months; 95% CI, 22.8-32.2 months; P = 0.0001), regardless of the time of metastatic presentation. In multivariate analysis, HV cohorts were confirmed associated with worse prognosis compared to those with LV (HV/PLT, HR = 1.87; p = 0.029; HV/DN, HR = 2.19; P = 0.002).

CONCLUSION

Our analysis suggests that the volume of disease could be a prognostic factor for patients starting AA or Enza as first-line treatment for metastatic castration-resistant prostate cancer, pending prospective clinical trial validation.

The safety of radium-223 combined with new-generation hormonal agents in bone metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

Patients with bone metastatic castration-resistant prostate cancer (mCRPC) might benefit from radium-223 (223Ra) combined with new-generation hormonal agents (NHAs) in terms of survival and quality of life (QoL). However, the safety of combination therapies remains unclear. Therefore, we aimed to perform a network meta-analysis by reviewing the literature about the combination of 223Ra with abiraterone acetate plus prednisone (AAP) or enzalutamide and to evaluate the safety of combination therapy in bone mCRPC patients. Ultimately, ten studies (2835 patients) were selected, including four randomized controlled trials (RCTs), five retrospective cohort studies, and one single-arm study. Overall, there was no difference in the incidence of fracture between the 223Ra+NHA combination group and the 223Ra monotherapy group (odds ratio [OR]: 1.46, 95% confidence interval [CI]: 0.91-2.34, P = 0.66), but the incidences in both the 223Ra+NHA combination group (OR: 3.22, 95% CI: 2.24-4.63, P < 0.01) and the 223Ra monotherapy group (OR: 2.24, 95% CI: 1.23-4.08, P < 0.01) were higher than that in the NHA monotherapy group. However, in the meta-analysis involving only RCTs, there was no difference between the 223Ra monotherapy group and the NHA monotherapy group (OR: 1.14, 95% CI: 0.22-5.95, P = 0.88), while the difference between the 223Ra+NHA combination group and the NHA monotherapy group remained significant (OR: 3.22, 95% CI: 2.24-4.63, P < 0.01). Symptomatic skeletal events (SSEs), SSE-free survival (SSE-FS), all grades of common adverse events (AEs), and ≥grade 3 AEs among all groups did not show any significant difference. Our results indicate that the combination of 223Ra with NHAs was well tolerated in bone mCRPC patients compared to 223Ra monotherapy, even though the incidence of fracture was higher in patients who received 223Ra than that among those who received NHA monotherapy. More evidence is needed to explore the safety and efficiency of 223Ra combination therapies.

Predictive factors for the efficacy of abiraterone acetate therapy in high-risk metastatic hormone-sensitive prostate cancer patients

PURPOSE

There is a discrepancy in the efficacy of abiraterone acetate for overall survival (OS) in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC). This study aimed to identify predictive factors for the efficacy of abiraterone acetate for OS in high-risk mHSPC patients by analyzing them over a longer observation period.

METHODS

Five hundred high-risk mHSPC patients were retrospectively identified at our hospital and affiliated hospitals in the Kindai Oncology Study Group and Kyoto Prefectural University of Medicine Oncology Study Group between December 2013 and March 2022. Two hundred patients were treated with abiraterone acetate (1000 mg/day) plus prednisolone (5 mg/day) combined with androgen deprivation therapy (ADT). A total of 300 patients were treated with bicalutamide (80 mg/day) in combination with ADT.

RESULTS

OS was not significantly different between the two treatments in the overall cohort (p = 0.1643). In the subgroup without Gleason pattern 5 at the primary lesion, OS was significantly better in patients treated with abiraterone acetate than in those treated with bicalutamide (p = 0.0192). In the subgroup with Gleason pattern 5 at the primary lesion, no significant difference was found between the two treatments (p = 0.1799). Univariate and multivariate analyses in the subgroup without Gleason pattern 5 at the primary lesion suggested that abiraterone therapy may be an important and independent predictor of OS in high-risk mHSPC patients.

CONCLUSION

The presence of Gleason pattern 5 at the primary lesion may be a predictor for high-risk mHSPC patients who could benefit from abiraterone acetate treatment.

Prognostic role of pan-immune-inflammation value in patients with metastatic castration-resistant prostate cancer treated with androgen receptor-signaling inhibitors

AIM

To assess the prognostic effect of pan-immune inflammation value (PIV) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA) or enzalutamide.

METHODS

Patients with mCRPC treated with AA or enzalutamide between January 2010 and June 2021 were included in this study. The most recently examined complete blood count values in the 1-month period before treatment were used for calculating PIV. The relationship between overall survival (OS) and PIV was evaluated by multivariate analysis. By using PIV and lactate dehydrogenase (LDH) levels which had shown survival effect at multivariate analysis, PIV-LDH combined score was established.

RESULTS

A total of 114 patients were included in this study. At the median follow-up of 34.6 months (95% confidence interval [CI]: 32.4-36.8), the median OS was 21 months (95% CI: 17.6-21.3). The median OS in the low-PIV group was significantly higher than in the high-PIV group (34.4 months (95% CI: 21.3-47.5) vs. 14.3 months (95% CI: 10.0-18.7), p < 0.001). In the multivariate analysis for OS, high PIV (hazard ratio [HR]: 1.86, 95% CI: 1.11-3.13, p = 0.018) and LDH value 1.5 times the upper limit of normal and above (HR: 3.65 95%, CI: 1.86-7.16, p < 0.001) were associated with shorter OS. When survival analysis was performed according to the PIV-LDH combined score, the median OS was 34.4 months (95% CI: 22.2-46.6) in the low-risk group, 17.7 months (95% CI: 11.7-23.6) in the intermediate-risk group, and 8.4 months (95% CI: 5.1-11.7) in the high-risk group (p < 0.001). The C-index of the combined PIV-LDH score was higher than the C-index of PIV (0.65 vs. 0.61).

CONCLUSION

In this study, we demonstrated that PIV was an independent prognostic factor for OS in patients with mCRPC treated with AA or enzalutamide. Additionally, PIV-LDH combined score may be considered a promising composite peripheral blood-based biomarker to predict OS in those patients.

Does Clinical Evidence of Heterogeneity Impact Treatment Selection? A Case Study of Abiraterone for Metastatic Prostate Cancer

BACKGROUND

Two pivotal randomized controlled trials (RCTs) demonstrate that abiraterone acetate + prednisone (AAP) combined with androgen deprivation therapy (ADT) significantly extends the survival of men with metastatic hormone-sensitive prostate cancer (mHSPC) compared with ADT alone. Their subgroup analyses indicate that the survival benefit is significant for younger men but not older men. We aimed to assess whether publication of the RCTs was associated with differential real-world AAP utilization by age groups.

METHODS

Using TriNetX electronic medical records data collected from 43 healthcare organizations across the United States, we performed a difference-in-differences event study among men with newly diagnosed mHSPC observed from June 2014 to June 2019. Eligible subjects were identified based on a comprehensive published algorithm. We analyzed the change in utilization rate of AAP before versus after publication of the RCTs among men aged &lt;70 years versus ≥70 years, adjusting for demographic factors and clinical conditions.

RESULTS

Our study included 6,888 men with newly diagnosed mHSPC with 12,738 observations, of whom 46% were aged &lt;70 years. The prepublication trends of AAP utilization were similar between the age groups, whereas publication of the RCTs was associated with a 3.5% higher adjusted uptake rate of AAP among younger men (95% CI, 1.2%-5.8%) relative to older men. This estimate reflects an uptake rate nearly 3 times higher than would have been expected had younger men followed the same utilization trends as older men. The estimates remained consistent throughout the postpublication period.

CONCLUSIONS

Our study suggests that publication of the RCTs was associated with faster uptake of AAP among younger versus older men with newly diagnosed mHSPC, despite the absence of clinical guidance for differential treatment selection. This finding highlights the importance of confirmatory studies among older men, considering the uncertainties of subgroup analyses in RCTs.

Serum prolactin level as a predictive factor for abiraterone response in patients with metastatic castration-resistant prostate cancer

BACKGROUND

To investigate the prognostic value and potential therapeutic target of the baseline serum hormones in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone.

METHODS

This retrospective study was performed in patients with mCRPC receiving abiraterone acetate (AA) from July 2016 to September 2020. Patients who had serum hormone tests within 2 weeks before AA treatment were included. Univariate analysis and Cox regression were performed to evaluate the correlation of sex hormones with progression-free survival (PFS) and overall survival (OS). Prolactin (PRL) expression in the clinical specimens was evaluated by immunohistochemistry. Bone metastases were quantified by automated Bone Scan Index (aBSI).

RESULTS

The study included 61 patients with a median follow-up of 19.0 months. Patients with lower baseline PRL levels (median) responded better to AA than those with higher baseline PRL levels as indicated by prostate-specific antigen (PSA) reduction (PSA90, 66.7% vs. 25.8%, p = 0.001), PFS (19.6 vs. 7.9 months), and OS (52.8 vs. 19.2 months). Cox regression adjusted for clinical factors also confirmed that baseline PRL level was an independent predictive factor for PFS (hazard ratio = 1.096, p = 0.007). Prostatic PRL expression increased as the disease progressed. PRL expression was also detected in biopsy samples from bone metastasis but not in normal bone tissue, and the serum PRL levels were positively correlated with aBSIs (r = 0.28, p = 0.037).

CONCLUSIONS

Serum PRL levels are predictive of response to AA in patients with mCRPC. Serum PRL levels are positively correlated with the volume of metastatic bone disease.

Abiraterone acetate plus prednisolone for metastatic patients starting hormone therapy: 5-year follow-up results from the STAMPEDE randomised trial (NCT00268476)

Abiraterone acetate plus prednisolone (AAP) previously demonstrated improved survival in STAMPEDE, a multiarm, multistage platform trial in men starting long-term hormone therapy for prostate cancer. This long-term analysis in metastatic patients was planned for 3 years after the first results. Standard-of-care (SOC) was androgen deprivation therapy. The comparison randomised patients 1:1 to SOC-alone with or without daily abiraterone acetate 1000 mg + prednisolone 5 mg (SOC + AAP), continued until disease progression. The primary outcome measure was overall survival. Metastatic disease risk group was classified retrospectively using baseline CT and bone scans by central radiological review and pathology reports. Analyses used Cox proportional hazards and flexible parametric models, accounting for baseline stratification factors. One thousand and three patients were contemporaneously randomised (November 2011 to January 2014): median age 67 years; 94% newly-diagnosed; metastatic disease risk group: 48% high, 44% low, 8% unassessable; median PSA 97 ng/mL. At 6.1 years median follow-up, 329 SOC-alone deaths (118 low-risk, 178 high-risk) and 244 SOC + AAP deaths (75 low-risk, 145 high-risk) were reported. Adjusted HR = 0.60 (95% CI: 0.50-0.71; P = 0.31 × 10^-9 ) favoured SOC + AAP, with 5-years survival improved from 41% SOC-alone to 60% SOC + AAP. This was similar in low-risk (HR = 0.55; 95% CI: 0.41-0.76) and high-risk (HR = 0.54; 95% CI: 0.43-0.69) patients. Median and current maximum time on SOC + AAP was 2.4 and 8.1 years. Toxicity at 4 years postrandomisation was similar, with 16% patients in each group reporting grade 3 or higher toxicity. A sustained and substantial improvement in overall survival of all metastatic prostate cancer patients was achieved with SOC + abiraterone acetate + prednisolone, irrespective of metastatic disease risk group.

Prognostic nutritional index is an independent prognostic factor for treatment response, survival and drug choice in metastatic castration-resistant prostate cancer treated with abiraterone acetate or enzalutamide

PURPOSE

We designed this study to identify the prognostic value of baseline prognostic nutritional index (PNI) in metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone acetate or enzalutamide.

METHODS

101 mCRPC patients were included. PNI was calculated using formula 10 x serum albumin value (gr/dL) + 0.005 × total lymphocyte count (per mm3). ROC analysis was used for determining prognostic PNI value.

RESULTS

The statistically significant cut-off value for PNI was 46.62. Initial PSA response and PSA kinetics (early PSA response and 30 %-50%-90% PSA response at any time) were much better in PNI > 46.62 group than the PNI ≤ 46.62 group (p < 0.01). In multivariate analysis, baseline PNI level >46.62 was an independent predictor of PSA-PFS (HR: 0.42, p < 0.01), radiologic PFS (HR: 0.53, p < 0.01), and OS (HR: 0.42, p < 0.01). In the PNI ≤ 46.62 group, median OS was 7.4 months (95% CI: 4.1-10.7) for the abiraterone acetate subgroup vs. 17.6 months (95% CI: 10.1-25.1) for enzalutamide subgroups (p < 0.01).

CONCLUSION

PNI is a useful, independent prognostic marker for mCRPC patients treated with either abiraterone acetate or enzalutamide. Using pre-treatment PNI may help clinicians in the prediction of survival and decision making based on abiraterone acetate or enzalutamide.

Cost-Effectiveness of Systemic Treatments for Metastatic Castration-Sensitive Prostate Cancer: An Economic Evaluation Based on Network Meta-Analysis

OBJECTIVES

To assess the cost-effectiveness of systemic treatments for metastatic castration-sensitive prostate cancer from the US healthcare sector perspective with a lifetime horizon.

METHODS

We built a partitioned survival model based on a network meta-analysis of 7 clinical trials with 7287 patients aged 36 to 94 years between 2004 and 2018 to predict patient health trajectories by treatment. We tested parameter uncertainties with probabilistic sensitivity analyses. We estimated drug acquisition costs using the Federal Supply Schedule and adopted generic drug prices when available. We measured cost-effectiveness by an incremental cost-effectiveness ratio (ICER).

RESULTS

The mean costs were approximately $392 000 with androgen deprivation therapy (ADT) alone and approximately $415 000, $464 000, $597 000, and $959 000 with docetaxel, abiraterone acetate, enzalutamide, and apalutamide, added to ADT, respectively. The mean quality-adjusted life-years (QALYs) were 3.38 with ADT alone and 3.92, 4.76, 3.92, and 5.01 with docetaxel, abiraterone acetate, enzalutamide, and apalutamide, added to ADT, respectively. As add-on therapy to ADT, docetaxel had an ICER of $42 069 per QALY over ADT alone; abiraterone acetate had an ICER of $58 814 per QALY over docetaxel; apalutamide had an ICER of $1 979 676 per QALY over abiraterone acetate; enzalutamide was dominated. At a willingness to pay below $50 000 per QALY, docetaxel plus ADT is likely the most cost-effective treatment; at any willingness to pay between $50 000 and $200 000 per QALY, abiraterone acetate plus ADT is likely the most cost-effective treatment.

CONCLUSIONS

These findings underscore the value of abiraterone acetate plus ADT given its relative cost-effectiveness to other systemic treatments for metastatic castration-sensitive prostate cancer.

Synthesis and characterization of epoxide impurities of abiraterone acetate

Abiraterone acetate is an antiandrogen steroidal drug that is used to treat patients with metastatic prostate cancer. During the process development of abiraterone acetate, two process α and β-epoxy abiraterone acetate related impurities (2 and 3) were observed along with the final API. In the present work we describe the synthesis of these two known impurities using abiraterone acetate in the presence of hydrogen peroxide and acetic acid as oxidizing agent. The structure of these impurities fully characterized by NMR, Mass, CHN and HPLC analysis.

P2Y1 agonist HIC in combination with androgen receptor inhibitor abiraterone acetate impairs cell growth of prostate cancer

P2Y receptors belong to the large superfamily of G-protein-coupled receptors and play a crucial role in cell death and survival. P2Y1 receptor has been identified as a marker for prostate cancer (PCa). A previously unveiled selective P2Y1 receptor agonist, the indoline-derived HIC (1-(1-((2-hydroxy-5-nitrophenyl)(4-hydroxyphenyl)methyl)indoline-4-carbonitrile), induces a series of molecular and biological responses in PCa cells PC3 and DU145, but minimal toxicity to normal cells. Here, we evaluated the combinatorial effect of HIC with abiraterone acetate (AA) targeted on androgen receptor (AR) on the inhibition of PCa cells. Here, the presence of HIC and AA significantly inhibited cell proliferation of PC3 and DU145 cells with time-dependent manner as a synerfistic combination. Moreover, it was also shown that the anticancer and antimetastasis effects of the combinratorial drugs were noticed through a decrease in colony-forming ability, cell migration, and cell invasion. In addition, the HIC + AA induced apoptotic population of PCa cells as well as cell cycle arrest in G1 progression phase. In summary, these studies show that the combination of P2Y1 receptor agonist, HIC and AR inhibitor, AA, effectively improved the antitumor activity of each drug. Thus, the combinatorial model of HIC and AA should be a novel and promising therapeutic strategy for treating prostate cancer.

Quality of Life in Men With Prostate Cancer Randomly Allocated to Receive Docetaxel or Abiraterone in the STAMPEDE Trial

PURPOSE

Docetaxel and abiraterone acetate plus prednisone or prednisolone (AAP) both improve survival when commenced alongside standard of care (SOC) androgen deprivation therapy in locally advanced or metastatic hormone-sensitive prostate cancer. Thus, patient-reported quality of life (QOL) data may guide treatment choices.

METHODS

A group of patients within the STAMPEDE trial were contemporaneously enrolled with the possibility of being randomly allocated to receive either docetaxel + SOC or AAP + SOC. A mixed-model assessed QOL in those who had completed at least one QLQ-C30 + PR25 questionnaire. The primary outcome measure was difference in global-QOL (QLQ-C30 Q29&30) between patients allocated to docetaxel + SOC or AAP + SOC over the 2 years after random assignment, with a predefined criterion for clinically meaningful difference of > 4.0 points. Secondary outcome measures included longitudinal comparison of functional domains, pain, and fatigue, plus global-QOL at defined timepoints.

RESULTS

Five hundred fifteen patients (173 docetaxel + SOC and 342 AAP + SOC) were included. Baseline characteristics, proportion of missing data, and mean baseline global-QOL scores (docetaxel + SOC 77.8 and AAP + SOC 78.0) were similar. Over the 2 years following random assignment, the mean modeled global-QOL score was +3.9 points (95% CI, +0.5 to +7.2; P = .022) higher in patients allocated to AAP + SOC. Global-QOL was higher for patients allocated to AAP + SOC over the first year (+5.7 points, 95% CI, +3.0 to +8.5; P < .001), particularly at 12 (+7.0 points, 95% CI, +3.0 to +11.0; P = .001) and 24 weeks (+8.3 points, 95% CI, +4.0 to +12.6; P < .001).

CONCLUSION

Patient-reported QOL was superior for patients allocated to receive AAP + SOC, compared with docetaxel + SOC over a 2-year period, narrowly missing the predefined value for clinical significance. Patients receiving AAP + SOC reported clinically meaningful higher global-QOL scores throughout the first year following random assignment.

Urinary microRNAs can predict response to abiraterone acetate in castration resistant prostate cancer: A pilot study

BACKGROUND

Despite novel agents have been introduced to treat castration resistant prostate cancer (CRPC) during the last decade, up to one-third of CRPC patients face primary resistance to new generation compounds. Therefore, sensitive molecular tools are urgently needed for reliable treatment selection and response prediction. This study aimed to evaluate urinary miRNAs and blood circulating androgen receptor (AR) transcript level as a tool for noninvasive outcome prediction for CRPC patients undergoing abiraterone acetate (AA) therapy.

METHODS

Prostate cancer-specific miR-148a, -365, -375, and -429 were analyzed in 129 urine samples collected from 100 CRPC patients before and during AA therapy via quantitative reverse transcription PCR. To test the prognostic value, urinary miRNA levels alone, as well as combined with AR level were associated with progression-free survival (PFS) and overall survival (OS).

RESULTS

Level of urinary miR-375 was the highest in CRPC in comparison to noncancerous controls, as well as in combination with miR-429 was predictive for short PFS in AA-treated patients (HR = 2.2, 95% CI: 1.1-4.2, p = 0.023). Especially high prognostic power of all analyzed miRNAs was observed in CRPC cases with high blood AR levels. For PFS prediction a tandem of miR-429 and high AR reached HR of 5.0 (95% CI: 2.2-11.8, p < 0.001), while for prediction of OS the best combination was demonstrated by miR-148a and AR with HR of 3.1 (95% CI: 1.4-7.1, p = 0.006).

CONCLUSIONS

Urinary miRNAs could be used as prognostic biomarkers for CRPC patients to predict response to AA therapy, especially for the cases with high blood AR levels.

Cost-utility analysis of adding abiraterone acetate plus prednisone/prednisolone to long-term hormone therapy in newly diagnosed advanced prostate cancer in England: Lifetime decision model based on STAMPEDE trial data

Adding abiraterone acetate (AA) plus prednisolone (P) to standard of care (SOC) improves survival in newly diagnosed advanced prostate cancer (PC) patients starting hormone therapy. Our objective was to determine the value for money to the English National Health Service (NHS) of adding AAP to SOC. We used a decision analytic model to evaluate cost-effectiveness of providing AAP in the English NHS. Between 2011-2014, the STAMPEDE trial recruited 1917 men with high-risk localised, locally advanced, recurrent or metastatic PC starting first-line androgen-deprivation therapy (ADT), and they were randomised to receive SOC plus AAP, or SOC alone. Lifetime costs and quality-adjusted life-years (QALYs) were estimated using STAMPEDE trial data supplemented with literature data where necessary, adjusting for baseline patient and disease characteristics. British National Formulary (BNF) prices (£98/day) were applied for AAP. Costs and outcomes were discounted at 3.5%/year. AAP was not cost-effective. The incremental cost-effectiveness ratio (ICER) was £149,748/QALY gained in the non-metastatic (M0) subgroup, with 2.4% probability of being cost-effective at NICE's £30,000/QALY threshold; and the metastatic (M1) subgroup had an ICER of £47,503/QALY gained, with 12.0% probability of being cost-effective. Scenario analysis suggested AAP could be cost-effective in M1 patients if priced below £62/day, or below £28/day in the M0 subgroup. AAP could dominate SOC in the M0 subgroup with price below £11/day. AAP is effective for non-metastatic and metastatic disease but is not cost-effective when using the BNF price. AAP currently only has UK approval for use in a subset of M1 patients. The actual price currently paid by the English NHS for abiraterone acetate is unknown. Broadening AAP's indication and having a daily cost below the thresholds described above is recommended, given AAP improves survival in both subgroups and its cost-saving potential in M0 subgroup.

Combined 177 Lu-PSMA-617 PRLT and abiraterone acetate versus 177 Lu-PSMA-617 PRLT monotherapy in metastatic castration-resistant prostate cancer: An observational study comparing the response and durability

OBJECTIVE

The aim of present study was to determine and compare the overall response rates, progression-free survival (PFS), overall survival (OS), and clinical toxicity of the combination of 177Lu-PSMA-617 radioligand therapy (PRLT) and abiraterone acetate (AA) versus 177Lu-PSMA-617 PRLT as monotherapy in metastatic castration-resistant prostate cancer (mCRPC) patients.

MATERIALS AND METHODS

The mCRPC patients who received at least one cycle of ¹⁷⁷ Lu-PSMA-617 PRLT with or without AA therapy, were included and analyzed in the present study. The patients were divided into two major groups. Group 1 received only ¹⁷⁷ Lu-PSMA PRLT and Group 2 received combined ¹⁷⁷ Lu-PSMA PRLT + AA therapy. Therapeutic dose of ¹⁷⁷ Lu-PSMA-617 PRLT was 4.4-5.55 GBq per patient per cycle administered at intervals of 10-12 weeks in both groups. The Group 2 patients additionally received a dose of 1000 mg of AA once daily and 5 mg of prednisone twice daily. Treatment response in two groups was evaluated under four broad categories (a) symptomatic, (b) biochemical (serum prostate-specific antigen level), (c) objective molecular imaging (⁶⁸ Ga-PSMA-11 and ¹⁸ F-FDG PET/CT), and (d) objective anatomical imaging (computed tomography). For assessing treatment response, patients in two groups were categorized into responders (complete response [CR], partial response [PR], and stable disease [SD]) and nonresponders (progressive disease [PD]). The Kaplan-Meier product-limit method was used to calculate PFS and OS following first ¹⁷⁷ Lu-PSMA PRLT in the two groups. Univariate analysis was used to compare the patients' characteristics in two groups using a χ² or Fisher exact test. The Kaplan-Meier curves of PFS and OS between two groups were compared by using the log-rank test (p < 0.05 significant).

RESULTS

A total of 58 mCRPC patients (Group 1, 38 patients and Group 2, 20 patients) were included in this study analysis. The clinical and demographic characteristics of these patients (age, Gleason score, FDG avid disease, metastatic disease burden, and average number of ¹⁷⁷ Lu-PSMA PRLT cycles) in two groups were compared and found to be similar (p > 0.05). Post-treatment, symptomatic, biochemical, molecular, and anatomic imaging responders were found in 22 patients (58%) and 17 patients (85%), 22 patients (58%) and 16 patients (80%), 19 patients (54%) and 14 patients (78%), and 19 patients (54%) and 14 patients (78%) in Group 1 and Group 2, respectively. The median PFS of 7 months and median OS of 8 months were documented in Group 1, whereas median PFS was not reached and median OS of 16 months registered in Group 2. Transient hematological toxicity of Grades 1 and 2 was found in total seven patients (five patients in Group 1 and two patients in Group 2). On comparison of the treatment outcome between two groups, significant p value was found for symptomatic responders (58% in Group 1 vs. 85% in Group 2), median PFS (7 months in Group 1 vs. not reached in Group 2), and median OS (8 months in Group 1 vs. 16 months in Group 2), with better outcome in Group 2 patients for these variables.

CONCLUSION

In the present study, the combination of ¹⁷⁷ Lu-PSMA-617 PRLT and AA therapy showed significant improvement in mCRPC patients' symptomatic response, PFS, and OS as compared to ¹⁷⁷ Lu-PSMA-617 PRLT monotherapy.

Prostate Cancer Metastasis to the Pituitary Gland Manifesting as Corticosteroid Withdrawal, and the Impact of the Switch from Prednisone to Dexamethasone on Survival Time

Despite improvements in the diagnosis and treatment of cancers, the incidence of pituitary metastasis has increased. Prostate cancer metastasis to the pituitary, however, is rare, and these tumors usually grow rapidly. They are also more likely to be located in the posterior pituitary, and the presenting symptoms are often nonspecific, which makes early diagnosis challenging. The management of this condition is usually multidisciplinary, and requires careful assessment and decision making. We present a case of a patient who developed prostate cancer metastasis to the pituitary. In this report, we show that patients with prostate cancer on corticosteroid therapy who develop withdrawal symptoms or other endocrine symptoms should be assessed for pituitary and other brain metastasis. This case report also discusses the impact of switching from prednisone and abiraterone to dexamethasone and abiraterone. Our report shows that patients on abiraterone and prednisone whose PSA has increased, but who have no radiologic progression, may have their PSA controlled and thereby improved survival time when they are switched to abiraterone and dexamethasone.

Apalutamide plus abiraterone acetate and prednisone versus placebo plus abiraterone and prednisone in metastatic, castration-resistant prostate cancer (ACIS): a randomised, placebo-controlled, double-blind, multinational, phase 3 study

BACKGROUND

The majority of patients with metastatic castration-resistant prostate cancer (mCRPC) will have disease progression of a uniformly fatal disease. mCRPC is driven by both activated androgen receptors and elevated intratumoural androgens; however, the current standard of care is therapy that targets a single androgen signalling mechanism. We aimed to investigate the combination treatment using apalutamide plus abiraterone acetate, each of which suppresses the androgen signalling axis in a different way, versus standard care in mCRPC.

METHODS

ACIS was a randomised, placebo-controlled, double-blind, phase 3 study done at 167 hospitals in 17 countries in the USA, Canada, Mexico, Europe, the Asia-Pacific region, Africa, and South America. We included chemotherapy-naive men (aged ≥18 years) with mCRPC who had not been previously treated with androgen biosynthesis signalling inhibitors and were receiving ongoing androgen deprivation therapy, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and a Brief Pain Inventory-Short Form question 3 (ie, worst pain in the past 24 h) score of 3 or lower. Patients were randomly assigned (1:1) via a centralised interactive web response system with a permuted block randomisation scheme (block size 4) to oral apalutamide 240 mg once daily plus oral abiraterone acetate 1000 mg once daily and oral prednisone 5 mg twice daily (apalutamide plus abiraterone-prednisone group) or placebo plus abiraterone acetate and prednisone (abiraterone-prednisone group), in 28-day treatment cycles. Randomisation was stratified by presence or absence of visceral metastases, ECOG performance status, and geographical region. Patients, the investigators, study team, and the sponsor were masked to group assignments. An independent data-monitoring committee continually monitored data to ensure ongoing patient safety, and reviewed efficacy data. The primary endpoint was radiographic progression-free survival assessed in the intention-to-treat population. Safety was reported for all patients who received at least one dose of study drug. This study is completed and no longer recruiting and is registered with ClinicalTrials.gov, number NCT02257736.

FINDINGS

982 men were enrolled and randomly assigned from Dec 10, 2014 to Aug 30, 2016 (492 to apalutamide plus abiraterone-prednisone; 490 to abiraterone-prednisone). At the primary analysis (median follow-up 25·7 months [IQR 23·0-28·9]), median radiographic progression-free survival was 22·6 months (95% CI 19·4-27·4) in the apalutamide plus abiraterone-prednisone group versus 16·6 months (13·9-19·3) in the abiraterone-prednisone group (hazard ratio [HR] 0·69, 95% CI 0·58-0·83; p<0·0001). At the updated analysis (final analysis for overall survival; median follow-up 54·8 months [IQR 51·5-58·4]), median radiographic progression-free survival was 24·0 months (95% CI 19·7-27·5) versus 16·6 months (13·9-19·3; HR 0·70, 95% CI 0·60-0·83; p<0·0001). The most common grade 3-4 treatment-emergent adverse event was hypertension (82 [17%] of 490 patients receiving apalutamide plus abiraterone-prednisone and 49 [10%] of 489 receiving abiraterone-prednisone). Serious treatment-emergent adverse events occurred in 195 (40%) patients receiving apalutamide plus abiraterone-prednisone and 181 (37%) patients receiving abiraterone-prednisone. Drug-related treatment-emergent adverse events with fatal outcomes occurred in three (1%) patients in the apalutamide plus abiraterone-prednisone group (2 pulmonary embolism, 1 cardiac failure) and five (1%) patients in the abiraterone-prednisone group (1 cardiac failure and 1 cardiac arrest, 1 mesenteric arterial occlusion, 1 seizure, and 1 sudden death).

INTERPRETATION

Despite the use of an active and established therapy as the comparator, apalutamide plus abiraterone-prednisone improved radiographic progression-free survival. Additional studies to identify subgroups of patients who might benefit the most from combination therapy are needed to further refine the treatment of mCRPC.

FUNDING

Janssen Research & Development.

A prospective trial of abiraterone acetate plus prednisone in Black and White men with metastatic castrate-resistant prostate cancer

BACKGROUND

Retrospective analyses of randomized trials suggest that Black men with metastatic castration-resistant prostate cancer (mCRPC) have longer survival than White men. The authors conducted a prospective study of abiraterone acetate plus prednisone to explore outcomes by race.

METHODS

This race-stratified, multicenter study estimated radiographic progression-free survival (rPFS) in Black and White men with mCRPC. Secondary end points included prostate-specific antigen (PSA) kinetics, overall survival (OS), and safety. Exploratory analysis included genome-wide genotyping to identify single nucleotide polymorphisms associated with progression in a model incorporating genetic ancestry. One hundred patients self-identified as White (n = 50) or Black (n = 50) were enrolled. Eligibility criteria were modified to facilitate the enrollment of individual Black patients.

RESULTS

The median rPFS for Black and White patients was 16.6 and 16.8 months, respectively; their times to PSA progression (TTP) were 16.6 and 11.5 months, respectively; and their OS was 35.9 and 35.7 months, respectively. Estimated rates of PSA decline by ≥50% in Black and White patients were 74% and 66%, respectively; and PSA declines to <0.2 ng/mL were 26% and 10%, respectively. Rates of grade 3 and 4 hypertension, hypokalemia, and hyperglycemia were higher in Black men.

CONCLUSIONS

Multicenter prospective studies by race are feasible in men with mCRPC but require less restrictive eligibility. Despite higher comorbidity rates, Black patients demonstrated rPFS and OS similar to those of White patients and trended toward greater TTP and PSA declines, consistent with retrospective reports. Importantly, Black men may have higher side-effect rates than White men. This exploratory genome-wide analysis of TTP identified a possible candidate marker of ancestry-dependent treatment outcomes.

Association of Concomitant Bone Resorption Inhibitors With Overall Survival Among Patients With Metastatic Castration-Resistant Prostate Cancer and Bone Metastases Receiving Abiraterone Acetate With Prednisone as First-Line Therapy

IMPORTANCE

Bone resorption inhibitors (BRIs) are recommended by international guidelines to prevent skeletal-related events (SREs) among patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastases. Abiraterone acetate with prednisone is currently the most common first-line therapy for the treatment of patients with mCRPC; however, the clinical impact of the addition of BRIs to abiraterone acetate with prednisone in this disease setting is unknown.

OBJECTIVE

To evaluate the association of the use of concomitant BRIs with overall survival (OS) and time to first SRE among patients with mCRPC and bone metastases receiving abiraterone acetate with prednisone as first-line therapy.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study collected data from 745 consecutive patients who began receiving abiraterone acetate with prednisone as first-line therapy for mCRPC with bone metastases between January 1, 2013, and December 31, 2016. Data were collected from 8 hospitals in Canada, Europe, and the US from June 15 to September 15, 2019.

EXPOSURES

Patients were classified by receipt vs nonreceipt of concomitant BRIs and subclassified by volume of disease (high volume or low volume, using definitions from the Chemohormonal Therapy Vs Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer [CHAARTED] E3805 study) at the initiation of abiraterone acetate with prednisone therapy.

MAIN OUTCOMES AND MEASURES

The primary end point was OS. The secondary end point was time to first SRE. The Kaplan-Meier method and Cox proportional hazards models were used.

RESULTS

Of the 745 men (median age, 77.6 years [interquartile range, 68.1-83.6 years]; 699 White individuals [93.8%]) included in the analysis, 529 men (71.0%) received abiraterone acetate with prednisone alone (abiraterone acetate cohort), and 216 men (29.0%) received abiraterone acetate with prednisone plus BRIs (BRI cohort). A total of 420 men (56.4%) had high-volume disease, and 276 men (37.0%) had low-volume disease. The median follow-up was 23.5 months (95% CI, 19.8-24.9 months). Patients in the BRI cohort experienced significantly longer OS compared with those in the abiraterone acetate cohort (31.8 vs 23.0 months; hazard ratio [HR], 0.65; 95% CI, 0.54-0.79; P < .001). The OS benefit in the BRI cohort was greater for patients with high-volume vs low-volume disease (33.6 vs 19.7 months; HR, 0.51; 95% CI, 0.38-0.68; P < .001). The BRI cohort also had a significantly shorter time to first SRE compared with the abiraterone acetate cohort (32.4 vs 42.7 months; HR, 1.27; 95% CI, 1.00-1.60; P = .04), and the risk of a first SRE was more than double in the subgroup with low-volume disease (HR, 2.29; 95% CI, 1.57-3.35; P < .001). In the multivariable analysis, concomitant BRIs use was independently associated with longer OS (HR, 0.64; 95% CI, 0.52-0.79; P < .001).

CONCLUSIONS AND RELEVANCE

In this study, the addition of BRIs to abiraterone acetate with prednisone as first-line therapy for the treatment of patients with mCRPC and bone metastases was associated with longer OS, particularly in patients with high-volume disease. These results suggest that the use of BRIs in combination with abiraterone acetate with prednisone as first-line therapy for the treatment of mCRPC with bone metastases could be beneficial.

Liquid biopsy reveals KLK3 mRNA as a prognostic marker for progression free survival in patients with metastatic castration-resistant prostate cancer undergoing first-line abiraterone acetate and prednisone treatment

Circulating RNAs extracted from liquid biopsies represent a promising source of cancer‐ and therapy‐related biomarkers. We screened whole blood from patients with metastatic castration‐resistant prostate cancer (mCRPC) following their first‐line treatment with abiraterone acetate and prednisone (AA‐P) to identify circulating RNAs that may correlate with progression‐free survival (PFS). In a prospective multicenter observational study, 53 patients with mCRPC were included after they started first‐line AA‐P treatment. Blood was drawn at baseline, 1, 3, and 6 months after treatment initiation. The levels of predefined circulating RNAs earlier identified as being upregulated in patients with mCRPC (e.g., microRNAs, long noncoding RNAs, and mRNAs), were analyzed. Uni‐ and multivariable Cox regression and Kaplan–Meier analyses were used to analyze the prognostic value of the various circulating RNAs for PFS along treatment. Detectable levels of kallikrein‐related peptidase 3 (KLK3) mRNA at baseline were demonstrated to be an independent prognostic marker for PFS (201 vs 501 days, P = 0.00054). Three months after AA‐P treatment initiation, KLK3 could not be detected in the blood of responding patients, but was still detectable in 56% of the patients with early progression. Our study confirmed that KLK3 mRNA detection in whole blood is an independent prognostic marker in mCRPC patients receiving AA‐P treatment. Furthermore, the levels of circulating KLK3 mRNA in patients receiving AA‐P treatment might reflect treatment response or early signs of progression.

Targeting backdoor androgen synthesis through AKR1C3 inhibition: A presurgical hormonal ablative neoadjuvant trial in high-risk localized prostate cancer

BACKGROUND

Localized prostate cancers (PCs) may resist neoadjuvant androgen receptor (AR)-targeted therapies as a result of persistent intraprostatic androgens arising through upregulation of steroidogenic enzymes. Therefore, we sought to evaluate clinical effects of neoadjuvant indomethacin (Indo), which inhibits the steroidogenic enzyme AKR1C3, in addition to combinatorial anti-androgen blockade, in men with high-risk PC undergoing radical prostatectomy (RP).

METHODS

This was an open label, single-site, Phase II neoadjuvant trial in men with high to very-high-risk PC, as defined by NCCN criteria. Patients received 12 weeks of apalutamide (Apa), abiraterone acetate plus prednisone (AAP), degarelix, and Indo followed by RP. Primary objective was to determine the pathologic complete response (pCR) rate. Secondary objectives included minimal residual disease (MRD) rate, defined as residual cancer burden (RCB) ≤ 0.25cm³ (tumor volume multiplied by tumor cellularity) and elucidation of molecular features of resistance.

RESULTS

Twenty patients were evaluable for the primary endpoint. Baseline median prostate-specific antigen (PSA) was 10.1 ng/ml, 4 (20%) patients had Gleason grade group (GG) 4 disease and 16 had GG 5 disease. At RP, 1 (5%) patient had pCR and 6 (30%) had MRD. Therapy was well tolerated. Over a median follow-up of 23.8 months, 1 of 7 (14%) men with pathologic response and 6 of 13 (46%) men without pathologic response had a PSA relapse. There was no association between prostate hormone levels or HSD3B1 genotype with pathologic response.

CONCLUSIONS

In men with high-risk PC, pCR rates remained low even with combinatorial AR-directed therapy, although rates of MRD were higher. Ongoing follow-up is needed to validate clinical outcomes of men who achieve MRD.

Real-World Safety and Efficacy Outcomes with Abiraterone Acetate Plus Prednisone or Prednisolone as the First- or Second-Line Treatment for Metastatic Castration-Resistant Prostate Cancer: Data from the Prostate Cancer Registry

BACKGROUND

Despite standard-of-care androgen-deprivation therapy and an increasing number of treatment options, the mortality rate for prostate cancer remains high. Progress to metastatic castration-resistant prostate cancer (mCRPC) necessitates additional treatments. Abiraterone acetate plus prednisone or prednisolone (AAP) prolongs survival in chemotherapy-naive and docetaxel-experienced patients.

OBJECTIVE

To evaluate the real-world safety and efficacy of AAP as first-line and second-line [post-docetaxel only (AAP-PD)] treatment in patients with mCRPC.

PATIENTS AND METHODS

The Prostate Cancer Registry (PCR) was a prospective, international, observational study of patients with mCRPC in routine clinical practice. Men aged ≥ 18 years with confirmed mCRPC were included. Baseline characteristics, safety (treatment-emergent adverse events, treatment-emergent severe adverse events), and efficacy [progression-free survival (PFS) and overall survival (OS)] were analyzed.

RESULTS

At baseline, patients who received first-line AAP (n = 754) were generally older than patients who received AAP-PD (n = 354); median age was 76 years and 70 years, respectively. However, the rate of visceral metastasis was higher in the AAP-PD cohort than in the AAP cohort (17.7% vs. 9.6%, respectively). Demographics and disease characteristics of patients with baseline cardiovascular disease were similar to those of the overall registry population. Efficacy outcomes were similar for all patients, regardless of the line of AAP therapy. For first-line AAP and AAP-PD, respectively, the median PFS was 8.9 and 5.8 months for all patients and 9.1 and 6.0 months for patients with cardiovascular comorbidities; median OS was 27.1 and 23.4 months for all patients, and 27.4 and 23.1 months for patients with cardiovascular comorbidities. There were no unexpected adverse events in any patient subgroup.

CONCLUSIONS

These real-world data complement the findings from randomized controlled trials, indicating that first- and second-line AAP is well tolerated and effective in patients with mCRPC, including those with underlying CV comorbidities.

TRIAL REGISTRATION NUMBER

NCT02236637, registered 8 September 2014.

Prognostic value of ECOG performance status and Gleason score in the survival of castration-resistant prostate cancer: a systematic review

Eastern Cooperative Oncology Group (ECOG) performance status and Gleason score are commonly investigated factors for overall survival (OS) in men with castration-resistant prostate cancer (CRPC). However, there is a lack of consistency regarding their prognostic or predictive value for OS. Therefore, we performed this meta-analysis to assess the associations of ECOG performance status and Gleason score with OS in CRPC patients and compare the two markers in patients under different treatment regimens or with different chemotherapy histories. A systematic literature review of monotherapy studies in CRPC patients was conducted in the PubMed database until May 2019. The data from 8247 patients in 34 studies, including clinical trials and real-world data, were included in our meta-analysis. Of these, twenty studies reported multivariate results and were included in our main analysis. CRPC patients with higher ECOG performance statuses (≥ 2) had a significantly increased mortality risk than those with lower ECOG performance statuses (<2), hazard ratio (HR): 2.10, 95% confidence interval (CI): 1.68-2.62, and P < 0.001. The synthesized HR of OS stratified by Gleason score was 1.01, with a 95% CI of 0.62-1.67 (Gleason score ≥ 8 vs <8). Subgroup analysis showed that there was no significant difference in pooled HRs for patients administered taxane chemotherapy (docetaxel and cabazitaxel) and androgen-targeting therapy (abiraterone acetate and enzalutamide) or for patients with different chemotherapy histories. ECOG performance status was identified as a significant prognostic factor in CRPC patients, while Gleason score showed a weak prognostic value for OS based on the available data in our meta-analysis.

Risk of major adverse cardiovascular events among second-line hormonal therapy for metastatic castration-resistant prostate cancer: A real-world evidence study

BACKGROUND

To evaluate the possible major adverse cardiovascular events (MACE) associated with second-line hormonal therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

We performed a population-based real-world cohort study of 4962 prostate cancer patients between 2014 and 2017 utilizing the Chang Gung Research Database of Taiwan. The second-line hormonal therapies included enzalutamide and abiraterone acetate. The outcomes of interest were MACE, including acute coronary syndrome (ACS), ischemic stroke (IS), and heart failure (HF) events that resulted in hospitalization. Cox proportional-hazards models with inverse probability of treatment weighting (IPTW) with propensity scores were used.

RESULTS

After IPTW, 288 patients were prescribed second-line hormonal therapy and 1575 received first-line androgen-deprivation therapy (ADT). Of all patients diagnosed with MACE, the event rates were 2.92% in the second-line hormonal group and 2.22% in the first-line ADT group. The mean follow-up period was 9.52 months for the second-line hormonal group. Patients who received second-line hormonal therapy exhibited a significantly increased risk for MACE (hazard ratio [HR]: 3.15; 95% confidence interval [CI]: 2.03-4.89), ACS (HR: 4.94; 95% CI: 2.36-10.33), and HF (HR: 2.83; 95% CI: 1.53-5.25), compared with the first-line ADT group, but a similar risk for IS was observed in both groups (HR: 1.70; 95% CI: 0.95-3.04).

CONCLUSIONS

The real-world evidence study revealed increased risks for MACE in mCRPC patients receiving second-line hormonal therapy.

Cost-Effectiveness Assessment of Monitoring Abiraterone Levels in Metastatic Castration-Resistant Prostate Cancer Patients

OBJECTIVES

Abiraterone acetate is registered for the treatment of metastatic castration-sensitive and resistant prostate cancer (mCRPC). Treatment outcome is associated with plasma trough concentrations (C_min) of abiraterone. Patients with a plasma C_min below the target of 8.4 ng/mL may benefit from treatment optimization by dose increase or concomitant intake with food. This study aims to investigate the cost-effectiveness of monitoring abiraterone C_min in patients with mCRPC.

METHODS

A Markov model was built with health states progression-free survival, progressed disease, and death. The benefits of monitoring abiraterone C_min followed by a dose increase or food intervention were modeled via a difference in the percentage of patients achieving adequate C_min taking a healthcare payer perspective. Deterministic and probabilistic sensitivity analyses were performed to assess uncertainties and their impac to the incremental cost-effectiveness ratio (ICER).

RESULTS

Monitoring abiraterone followed by a dose increase resulted in 0.149 incremental quality-adjusted life-years (QALYs) with €22 145 incremental costs and an ICER of €177 821/QALY. The food intervention assumed equal effects and estimated incremental costs of €7599, resulting in an ICER of €61 019/QALY. The likelihoods of therapeutic drug monitoring (TDM) with a dose increase or food intervention being cost-effective were 8.04%and 81.9%, respectively.

CONCLUSIONS

Monitoring abiraterone followed by a dose increase is not cost-effective in patients with mCRPC from a healthcare payer perspective. Monitoring in combination with a food intervention is likely to be cost-effective. This cost-effectiveness assessment may assist decision making in future integration of abiraterone TDM followed by a food intervention into standard abiraterone acetate treatment practices of mCRPC patients.

Abiraterone acetate in combination with androgen deprivation therapy compared to androgen deprivation therapy only for metastatic hormone-sensitive prostate cancer

BACKGROUND

Systemic androgen deprivation therapy (ADT), also referred to as hormone therapy,àhas long been the primary treatment for metastatic prostate cancer. Additional agents have been reserved for the castrate-resistant disease stage when ADT start becoming less effective. Abiraterone is an agent with an established role in that disease stage, which has only recently been evaluated in the hormone-sensitive setting.

OBJECTIVES

To assess the effects of early abiraterone acetate, in combination with systemic ADT, for newly diagnosed metastatic hormone-sensitive prostate cancer.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, six other databases, two trials registries, grey literature, and conference proceedings, up to 15 May 2020. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included randomized trials, in which men diagnosed with hormone-sensitive prostate cancer were administered abiraterone acetate and prednisolone with ADT or ADTàalone.

DATA COLLECTION AND ANALYSIS

Two review authors independently classified studies and abstracted data from the included studies. We performed statistical analyses using a random-effects model. We rated the quality of evidence according to the GRADE approach.

MAIN RESULTS

The search identified two randomized controlled trials (RCT), with 2201 men, who were assigned to receive either abiraterone acetate 1000 mg once daily and low dose prednisone (5mg) in addition to ADT, or ADT alone. In the LATITUDE trial, the median age and range of men in the intervention group was 68 (38 to 89) years, and 67 (33 to 92) years in the control group. Nearly all of the men in thisàstudy (97.6%) had prostate cancer with a Gleason score of at least 8 (ISUP grade group 4). Primary outcomes The addition of abiraterone acetate to ADT reduces the probability of death from any cause compared to ADT alone (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.56 to 0.73; 2 RCTs, 2201 men; high certainty of evidence); this corresponds to 163 fewer deaths per 1000 men with hormone-sensitive metastaticàprostate cancerà(210 fewer to 115 fewer) at five years. Abiraterone acetate in addition to ADT probably results in little to no differenceàin quality of life compared to ADT alone, measured with the Functional Assessment of Cancer Therapy-prostate total score (FACT-P; range 0 to 156; higher values indicates better quality of life),àat 12 months (mean difference [MD] 2.90 points, 95% CI 0.11 to 5.60; 1 RCT, 838 men; moderate certainty of evidence). Secondary outcomes Abiraterone plus ADT increases the risk of grades III to V adverse events compared to ADT alone (risk ratio [RR] 1.34, 95% CI 1.22 to 1.47; 1 RCT, 1199 men; high certainty of evidence); this corresponds to 162 more grade III to Vàevents per 1000 men with hormone-sensitive metastaticàprostate cancerà(105 more to 224 more) at a median follow-up of 30àmonths. Abiraterone acetate in addition to ADT probably reduces the probability of death due to prostate cancer compared to ADT alone (HR 0.58, 95% CI 0.50 to 0.68; 2 RCTs, 2201 men; moderate certainty of evidence). This corresponds to 120 fewer death from prostate cancer per 1000 men with hormone-sensitive metastaticàprostate cancerà(95% CI 145 fewer to 90 fewer) afteràa median follow-up of 30 months. The addition of abiraterone acetate to ADT probably decreases the probability of disease progression compared to ADT alone (HR 0.35, 95%CI 0.26 to 0.49; 2 RCTs, 2097 men; moderate certainty of evidence). This corresponds to 369 fewer incidences of disease progression per 1000 men with hormone-sensitive metastaticàprostate cancerà(456 fewer to 256 fewer)àafter a median follow-up of 30 months. The addition of abiraterone acetate to ADT probably increases the risk of discontinuing treatment due to adverse events compared to ADT alone (RR 1.50, 95% CI 1.17 to 1.92; 1 RCT, 1199 men; moderate certainty of evidence). This corresponds to 51 more men (95% CI 17 more to 93 more) discontinuing treatment because of adverse events per 1000 men treated with abiraterone acetate and ADT compared to ADT alone afteràa median follow-up of 30 months.

AUTHORS' CONCLUSIONS

The addition of abiraterone acetate to androgen deprivation therapy improves overall survival but probably not quality of life. Itàprobably also extends disease-specific survival, and delays disease progression compared to androgen deprivation therapy alone. However, the risk of grades III to V adverse events is increased, and probably, so is the risk of discontinuing treatment due to adverse events.

A Retrospective Observational Analysis of Overall Survival with Sipuleucel-T in Medicare Beneficiaries Treated for Advanced Prostate Cancer

Introduction

Since sipuleucel-T approval in 2010, the treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) now includes the androgen-receptor signaling pathway inhibitors (ASPIs) abiraterone acetate or enzalutamide. In 2013 and 2014, these oral agents were approved for use in men with metastatic prostate cancer who had minimal to no symptoms. We compared overall survival (OS) in men who received their first mCRPC treatment using the Medicare Fee-for-Service 100% administrative claims research dataset with patient-level linkage to the National Death Index.

Methods

This retrospective cohort analysis (January 2013 to December 2017) included men who were chemo-naïve at treatment start in 2014 and who had continuous Medicare Parts A, B, and D eligibility during the 3-year observation period. We compared: first-line sipuleucel-T vs. first-line ASPIs and any-line sipuleucel-T vs. any-line ASPIs (without sipuleucel-T). We used a multivariable regression model to help control for potentially confounding factors while assessing survival outcomes.

Results

The model included 6044 eligible men (average age 75–78 years) with similar disease severity; > 80% were white. Median OS, presented as sipuleucel-T vs. ASPI, was 35.2 vs. 20.7 months (n, 906 vs. 5092; any-line cohort) and 34.9 vs. 21.0 months (n, 647 vs. 4810; first-line cohort). Model outcomes indicated sipuleucel-T was associated with significantly prolonged OS compared with ASPIs: adjusted hazard ratio, 0.59 (95% CI 0.527–0.651) and 0.56 (0.494–0.627) for the any-line and first-line cohorts, respectively.

Conclusion

This analysis suggests use of sipuleucel-T at any time was associated with improved OS compared with ASPI use alone. Of note, these analyses are intended as descriptive rather than definitive as this dataset contains limited data on key clinical factors. While selection bias is a risk in secondary claims data, this research provides important insight into real-world treatment outcomes.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01509-5) contains supplementary material, which is available to authorized users.

Evaluation of Fall and Fracture Risk Among Men With Prostate Cancer Treated With Androgen Receptor Inhibitors: A Systematic Review and Meta-analysis

Importance

A high incidence of fall and fracture in a subset of patients treated with androgen receptor inhibitors (ARIs) has been reported, although the relative risk (RR) of fall and fracture for patients who receive ARI treatment is unknown.

Objective

To evaluate whether treatment with ARIs is associated with an elevated relative risk for fall and fracture in patients with prostate cancer.

Data Sources

Cochrane, Scopus, and MedlinePlus databases were searched from inception through August 2019.

Study Selection

Randomized clinical trials comparing patients with prostate cancer treated with any ARI or placebo were included.

Data Extraction and Synthesis

Two independent reviewers used a standardized data extraction and quality assessment form. A mixed effects model was used to estimate the effects of ARI on relative risk, with included studies treated as random effects and study groups treated as fixed effects in the pooled analysis. Sample size for each study was used to weight the mixed model. Statistical analysis was performed from August to October 2019.

Main Outcomes and Measures

The primary outcome was RR of fall and fractures for patients receiving ARI treatment.

Results

Eleven studies met this study's inclusion criteria. The total population was 11 382 men (median [range] age: 72 [43-97] years), with 6536 in the ARI group and 4846 in the control group. Participants in the ARI group could have received enzalutamide, apalutamide, or darolutamide in combination with androgen deprivation therapy or other enzalutamide combinations; patients in the control group could have received placebo, bicalutamide, or abiraterone. The reported incidence of fall was 525 falls (8%) in the ARI group and 221 falls (5%) in the control group. The incidence of fracture was 242 fractures (4%) in the ARI group and 107 fractures (2%) in the control group. Use of an ARI was associated with an increased risk of falls and fractures: all-grade falls (RR, 1.8; 95% CI, 1.42-2.24; P < .001); grade 3 or greater fall (RR, 1.6; 95% CI, 1.27-2.08; P < .001); all-grade fracture (RR, 1.59; 95% CI, 1.35-1.89; P < .001), and likely grade 3 or greater fracture (RR, 1.71; 95% CI, 1.12-2.63; P = .01).

Conclusions and Relevance

Use of ARI was associated with an increase in falls and fractures in patients with prostate cancer as assessed by a retrospective systematic review and meta-analysis. Further studies are warranted to identify and understand potential mechanisms and develop strategies to decrease falls and fractures associated with ARI use.