Early Prediction of Therapy Response to Abiraterone Acetate Using PSA Subforms in Patients with Castration Resistant Prostate Cancer

Prostate-specific antigen response after Abiraterone treatment in mCRPC: PSA as a predictor of overall survival

OBJECTIVES

Abiraterone Acetate (AA) is an important agent in the treatment of advanced prostate cancer. It was primarily approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC) after failure of androgen deprivation therapy. There is still no available strong data regarding the impact of early decline of prostate-specific antigen (PSA) in the overall survival. The aim of this study was to evaluate the clinical efficacy of an early prostate-specific antigen response as a predictor of overall survival (OS) in metastatic castration-resistant prostate cancer when treated with Abiraterone Acetate.

MATERIALS AND METHODS

A dual center, retrospective, cohort study on patients diagnosed with mCRPC treated with abiraterone between 2013 and 2020 was performed. Primary end-point was to demonstrate the efficacy of AA, with the analysis of PSA decline, and the correlation with overall survival.

RESULTS

The cohort analysis consisted of 84 patients with a median age of 71 ± 9 years. A PSA response of > 30% and > 50% at 60 and 90 days was associated with improved OS. Multivariate analysis revealed that a 60 day PSA decline of > 30% was predictive of overall survival. Median OS of diag-nosed mCRPC patients was 28 months. Docetaxel pre-treatment was not associated with longer OS. The median duration of drug exposure for patients submitted to AA was found to be 14 months.

CONCLUSIONS

Early PSA response rate can offer clinically meaningful information and can be considered a surrogate of longer OS. A > 30% or > 50% prostate-specific antigen decline at 60 and 90 days provided an important low-cost clinical tool to predict subsequent events in mCRPC patients treated with abiraterone.

The prognostic potential of alkaline phosphatase and lactic acid dehydrogenase in bmCRPC patients without significant PSA response under enzalutamide

Background

In patients with bone metastatic castration-resistant prostate cancer (bmCRPC) on systemic treatment, it is difficult to differentiate between continuous rise of prostate specific antigen (PSA) representing progression, and PSA-surge, which is followed by clinical response or stable disease. The purpose of this study was to evaluate the prognostic value of dynamic changes of alkaline phosphatase (ALP) and lactic acid dehydrogenase (LDH) levels as a predictor of clinical efficacy or therapeutic resistance of patients who do not show a sufficient initial PSA decline of ≥50% from baseline during early therapy with Enzalutamide.

Methods

Forty-eight men with bmCRPC on Enzalutamide 07/2010-09/2019 with initially rising PSA were analyzed. We monitored PSA, LDH and ALP at week 0, 2, 4, and every 4 weeks thereafter and analyzed the correlation between ALP rising at 12 weeks with or without LDH-normalization and the association with survival. For this we used Kaplan Meier analysis and uni- and multivariate cox-regression models.

Results

In Kaplan-Meier analysis, ALP rising at 12 weeks with or without LDH-normalization was associated with significantly worse median progression-free survival (PFS) of 3 months vs. 5 months (Log rank P = 0.02) and 3 months vs. 5 months (P = 0.01), respectively and overall survival (OS) with 8 months vs. 15 months (P = 0.02) and 8 months vs. 17 months (P < 0.01). In univariate analysis of PFS, ALP rising at 12 weeks alone, ALP rising at 12 weeks without LDH-normalization and application of Enzalutamide after chemotherapy showed a statistically significant association towards shorter PFS (hazard ratio (HR): 0.51, P = 0.04; HR: 0.48, P = 0.03; HR: 0.48, P = 0.03). Worse OS was significantly associated with ALP rising at 12 weeks alone, ALP rising at 12 weeks without LDH-normalization, and application of Enzalutamide after chemotherapy (HR: 0.47, P = 0.02; HR: 0.36, P < 0.01; HR: 0.31, P < 0.01). In multivariate analysis only the application of Enzalutamide after chemotherapy remained an independent prognostic factor for worse OS (HR: 0.36, P = 0.01).

Conclusions

Dynamic changes of ALP (non-rise) and LDH (normalization) under therapy with Enzalutamide may be associated with clinical benefit, better PFS, and OS in patients with bmCRPC who do not show a PSA decline.

ALP bouncing and LDH normalization in bone metastatic castration-resistant prostate cancer patients under therapy with Enzalutamide: an exploratory analysis

Background

In bone metastatic castration-resistant prostate cancer (bmCRPC) treated with Enzalutamide commonly used prostate-specific antigen (PSA) can be misleading since initial PSA-flares may occur. In other therapies, bouncing of alkaline phosphatase (ALP-bouncing) was shown to be a promising surrogate for survival outcome. Low lactate dehydrogenase (LDH) is usually associated with better outcome. We evaluated the prognostic ability of ALP-bouncing, LDH, PSA, and the combination of these markers after initiation of Enzalutamide.

Methods

Eighty-nine patients with bmCRPC and dynamic changes of PSA, LDH and ALP were analyzed. ALP-bouncing, an increase after therapy start followed by a decline below baseline during the first 8 weeks, LDH-normalization and PSA-decline were analyzed regarding their association with survival using Kaplan-Meier analyses and uni- and multivariate (UV and MV) Cox-regression models.

Results

In Kaplan-Meier analysis a PSA-decline >50%, LDH-normalization and ALP-bouncing were associated with longer median progression-free survival (PFS) with 7 [95% confidence interval (CI): 4.2-9.8] vs. 3 (2.3-3.7) months for PSA-decline (log-rank P<0.01), 6 (4.1-8) vs. 2 (1.2-2.8) for LDH-normalization (P<0.01) and 8 (0-16.3) vs. 3 (1.9-4.1) for ALP-bouncing (P=0.01). Analysis of overall survival (OS) showed similar, not for all parameters significant, results with 17 (11.7-22.3) vs. 12 (7.0-17.1) months for PSA (P=0.35), 17 (13.2-20.8) vs. 7 (5.8-8.2) for LDH-normalization (P<0.01) and 19 (7.9-30.1) vs. 12 (7.7-16.3) for ALP-bouncing (P=0.32). In UV analysis, ALP-bouncing [hazard ratio (HR): 0.5 (0.3-1.0); P=0.02], PSA-decline >50% [HR: 0.5 (0.3-0.7); P<0.01] and LDH-normalization [HR: 0.4 (0.2-0.6); P<0.01] were significantly associated with longer PFS. For OS, LDH-normalization significantly prognosticated longer survival [HR: 0.4 (0.2-0.6); P<0.01]. In MV analysis, LDH-normalization was associated with a trend towards better OS [HR: 0.5 (0.2-1.1); P=0.09]. Comparing ALP-bouncing, LDH-normalization and PSA-decline with a PSA-decline alone, Kaplan-Meier analysis showed significantly longer PFS [11 (0.2-21.8) vs. 4 (0-8.6); P=0.01] and OS [20 (17.7-22.3) vs. 8 (0.3-15.7); P=0.02] in favor of the group presenting with the beneficial dynamics of all three markers. In UV analysis, the presence of favorable changes in the three markers was significantly associated with longer PFS [HR: 0.2 (0.1-0.7); P<0.01] and OS [HR: 0.3 (0.1-0.8); P=0.02].

Conclusions

ALP-bouncing and LDH-normalization may add to identification of bmCRPC-patients with favorable prognosis under Enzalutamide.

Prognostic factors for patients treated with abiraterone

Aim:

To evaluate prostate-specific antigen response (PSAr) defined as a ≥50% decrease in PSA concentration from the pretreatment value, as a prognostic factor in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA).

Methods:

Retrospective evaluation of patients with mCRPC treated with AA.

Results:

124 patients were identified. Median overall survival and progression-free survival for patients achieving PSAr versus patients without PSAr were 29.3 versus 9.7 months and 17.0 versus 5.2 months, respectively. Multivariate analysis confirmed that PSAr correlated with better overall survival (hazard ratio: 0.19; 95% CI: 0.10−0.38; p < 0.001) and progression-free survival (hazard ratio: 0.24; 95% CI: 0.14−0.41; p < 0.001).

Conclusion:

PSAr can be utilized as prognostic and predictive factors in mCRPC patients treated with AA.

Therapeutic options for metastatic castration-resistant prostate cancer are expanding. However, biomarkers with predictive and prognostic value to assist in treatment guidance are lacking. The aim of this study was to evaluate prostate-specific antigen response as a prognostic factor in patients treated with abiraterone acetate. It was possible to confirm that prostate-specific antigen response correlated with better overall survival and progression-free survival in this patient cohort, evidencing the possible role of biochemical markers as surrogates for response and prognosis, especially in diseases that are difficult to evaluate radiographically.

Long-term clinical impact of PSA surge in castration-resistant prostate cancer patients treated with abiraterone

BACKGROUND

Early changes in PSA have been evaluated in association to treatment outcome. The aim of this study was to assess PSA surge phenomenon in castration-resistant prostate cancer (CRPC) patients treated with abiraterone and to correlate those variations with long-term treatment outcome.

PATIENTS AND METHODS

We retrospectively evaluated 330 CRPC patients in 11 Italian hospitals, monitoring PSA levels at baseline and every 4 weeks. Other clinical, biochemical and molecular parameters were determined at baseline. We considered PSA surge as PSA increase within the first 8 weeks from starting abiraterone more than 1% from baseline followed by a PSA decline. The log-rank test was applied to compare survival between groups of patients according to PSA surge. The impact of PSA surge on survival was evaluated by Cox regression analyses.

RESULTS

A total of 330 patients with CRPC, median age 74 years (range, 45-90), received abiraterone (281 chemotherapy-treated and 49 chemotherapy-naïve). PSA surge was observed in 20 (7%) post-chemotherapy and 2 (4%) chemotherapy-naïve patients. For overall patients presenting PSA surge, timing of PSA peak from baseline was 5 ± 1.8 weeks and PSA rise from baseline was 21 ± 18.4%. The overall median follow-up was 23 months (range 1-62). No significant differences in progression-free survival and overall survival were observed between patients with and without PSA surge (P = 0.16 and =0.86, respectively). In addition, uni- and multivariate analyses showed no baseline factors related to PSA surge.

CONCLUSION

PSA surge occurs in both chemotherapy-treated and chemotherapy-naïve patients treated with abiraterone resulting, however, in no long-term impact on outcome. Physicians and patients should be aware of PSA surge challenge to prevent a premature discontinuation of potentially effective therapy with abiraterone. Further larger and prospective studies are warranted to investigate this not infrequent phenomenon.