Docetaxel and prednisone with or without enzalutamide as first-line treatment in patients with metastatic castration-resistant prostate cancer: CHEIRON, a randomised phase II trial

Current androgen receptor antagonists under investigation for resistant prostate cancer: progress and challenges

INTRODUCTION

Prostate cancer represents a significant oncological challenge, with its natural history predominantly driven by androgen receptor (AR) signaling. The pivotal role of this pathway underscores the rationale for targeting AR activity in therapeutic strategies. However, the development of resistance mechanisms has highlighted the need for advanced therapies to address the complexity of the castration-resistant status.

AREAS COVERED

We analyzed the evolving role of second-generation androgen receptor signaling inhibitors (ARSIs) in the management of non-metastatic and metastatic castration-resistant prostate cancer, we critically examine emerging combination strategies involving ARSIs, novel agents targeting resistance pathways, and the mechanisms underlying treatment resistance. The review also provides insights into future directions for enhancing outcomes. PubMed literature research using keywords related to castration-resistant prostate cancer and its treatments was performed, including the most relevant trials and reviews.

EXPERT OPINION

ARSIs have revolutionized the management of prostate cancer, providing substantial clinical benefits and representing the cornerstone of current treatment paradigms. However, key challenges remain, including determining optimal treatment sequencing, overcoming resistance mechanisms, and tailoring therapies to specific molecular subtypes. Biomarker-driven approaches are critical for refining patient selection and improving therapeutic outcomes. Ongoing trials investigating novel hormonal-axis-directed agents and innovative combination therapies aim to expand the arsenal of effective treatment.

Systemic treatment options for metastatic castration resistant prostate cancer: A living systematic review

Background

Optimal treatment selection for metastatic castration resistant prostate cancer (mCRPC) remains challenging due to evolving standards of care in castration sensitive setting.

Purpose

To synthesize and appraise evidence on systemic therapy for mCRPC patients stratified by prior therapy and HRR alterations informing a clinical practice guideline.

Data Sources

MEDLINE and EMBASE (inception to 5 March 2025) using living search.

Study Selection

Randomized clinical trials assessing systemic therapy in mCRPC.

Data Extraction

Primary outcomes assessed were progression free survival (PFS) and overall survival (OS).

Data Synthesis

This report of the living systematic review (LSR) includes 143 trials with 17,523 patients (59 phase III/IV trials, 8,941 patients; 84 phase II, 8,582 patients). In the setting of prior androgen deprivation therapy (ADT) alone or ADT+docetaxel, treatment benefit was observed with poly (ADP-ribose) polymerase inhibitors (PARPi) in combination with androgen receptor pathway inhibitors (ARPI) for BRCA+ subgroup. In the setting of prior ADT+ARPI or ADT+ARPI+docetaxel, treatment benefit was observed with PARPi monotherapy for BRCA+ subgroup. Treatment benefit with PARPi may be observed for select non-BRCA homologous recombination repair (HRR) alterations (CDK12, PALB2). Treatment benefit was observed with abiraterone, enzalutamide, cabazitaxel, docetaxel (if no prior docetaxel), and Lu177 (if PSMA+) for patients without HRR alterations.

Limitations

Study-level data and indirectness in evidence.

Conclusion

Findings from the current LSR suggest that optimal treatment for mCRPC should be individualized based on prior therapy and HRR alterations. Current evidence favors PARPi alone (ARPI exposed) or in combination with ARPI (ARPI naïve) for patients with BRCA alterations, while ARPI alone, chemotherapy, and Lu177 remain potential options for patients without HRR alterations.

Enzalutamide and Docetaxel in Combination With Androgen Deprivation for Men With Metastatic Hormone-Sensitive Prostate Cancer: ENZADA, a Phase II Trial

BACKGROUND

Androgen receptor pathway inhibitors (ARPI) in combination with docetaxel (Doc) and androgen deprivation therapy (ADT) has improved outcomes for men with metastatic hormone sensitive prostate cancer (mHSPC). We hypothesized that combining ADT with Doc and enzalutamide (Enz) would improve the 52-week prostate-specific antigen (PSA) complete response (CR) rate compared to a historical control with ADT + Doc.

METHODS

In a single arm phase II trial, treatment-naïve patients with mHSPC received ADT + Doc every 3 weeks up to 6 cycles and Enz daily until progression. The primary endpoint was 52-week PSA CR. Secondary endpoints included safety/toxicity, best PSA response, time to castration resistance and overall survival (OS).

RESULTS

Between Sep 2017 and Aug 2021, 40 patients were enrolled and 36 evaluable for the primary endpoint. At data cutoff, median follow up was 56.1 months. Thirty patients (75%) had high-volume disease. Median age was 64.5 years. Median pretreatment PSA was 129.5ng/ml. 52-week PSA CR occurred in 22/36 (61.1%) patients compared to historical control (P < .001). Median OS was not reached. Patients who did not achieve a 52-week PSA CR had shorter OS (HR, 4.67; 95% CI 1.41-15.55; P = .006). Treatment-related Grade 3 to 5 adverse events occurred in 17/40 (42.5%) patients.

CONCLUSION

ADT+Doc+Enz improved 52-week PSA CR compared to historical control with ADT+Doc. Achieving a PSA CR after 1 year of therapy correlated with improved OS. These results are consistent with recent phase III studies and support using triplet regimens that combine ADT+Doc+ARPI for newly diagnosed mHSPC.

Comparative therapeutic efficacy and safety of first-line and second-line therapies for metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

Background

There is no cross-sectional comparison on therapeutic and adverse effects for treatments of metastatic castration-resistant prostate cancer (mCRPCa). We aimed to horizontally compare them for all common first-line and second-line therapies.

Methods

We conducted a network meta-analysis with a systematic review in four databases (Pubmed, Web of Science, Embase, and Cochrane Library) up to January 5th, 2025. All randomized controlled trials (RCT) related to mCRPCa treatments with a clear description in study design were included. Endpoints included the radiographic progression-free survival (rPFS), overall survival (OS), time to PSA progression (TTPP), PSA progression rate (PSARR), and adverse events. All data was extracted by two researchers and analyzed with Gemtc package in R and Stata15. This NMA protocol was registered online (ID: CRD42025633178).

Findings

After screening among 33,694 articles, 24 RCTs involving 13,059 cases were included. For first-line treatments, combination therapies with second-generation androgen receptor inhibitors (ARIs) showed superior efficacies in OS [HR of poly(ADP-ribose) polymerase inhibitors (PARPi) + ARI: 0.63 (0.32,1.25)], TTPP [HR of Lu177 + ARI: 0.07 (0.01,0.87)] and PSARR [RR of Lu177 + ARI: 33.02 (15.56,71.62)] with the highest SUCRA (Surface under the Cumulative Ranking Curve) (72%, 91% and 97% respectively). PARPi + ARI also performed best for rPFS (SUCRA: 85%, with an insignificant HR [0.12 (0.02,2.35)]. For post-docetaxel second-line treatments, ARI also emerged as the preferred option. Efficacies of post-ARI second-line treatments were not evaluated due to the lack of related RCTs. No obvious heterogeneity and publication bias was detected during the therapeutic comparison.

Interpretation

This study provided comparative evidence for first-line and post-chemotherapy second-line mCRPCa treatment options. Second-generation ARIs exhibited good efficacy, particularly when combined with other treatments. However, the safety analysis necessitated balance between benefits and adverse events, especially for combination therapies. Stronger evidence is needed through direct comparisons in future clinical trials.

Funding

The study was supported by The National Natural Science Foundation of China (No. 82172568).

Assessment of the therapeutic efficacy of [177Lu]Lu-PSMA-X compared to taxane chemotherapy in taxane-chemo-naïve patients with metastatic castration-resistant prostate cancer: A systematic review and meta-analysis

INTRODUCTION AND AIM

Radioligand therapy (RLT) with 177Lu-labelled prostate specific membrane antigen ([177Lu]Lu-PSMA-X, referring with "PSMA-X" to a generic PSMA chemical compound) inhibitors has emerged as a viable treatment option in metastatic castration resistant prostate cancer patients having previously progressed on taxane and androgen receptor inhibitors. The aim of this study was to perform a systematic review and meta-analysis to assess the therapeutic efficacy of [177Lu]Lu-PSMA-X compared to taxane chemotherapy in taxane-chemo-naïve patients with metastatic castration-resistant prostate cancer.

MATERIALS AND METHODS

Searches in several bibliographic databases were made using relevant key words, and articles published up to March 2024 were included. The endpoints included prostate specific antigen (PSA) response rate (RR), progression-free survival, and overall survival. Individual patient data were pooled when feasible. PSA50 was defined as the median proportion of patients achieving at least a 50% decline in serum PSA from baseline. A meta-analysis of the PSA50 response rate (proportion meta-analysis) was performed, generating pooled estimates and 95% confidence intervals (95% CI).

RESULTS

From the initially selected 8,414 studies published between 2019 and 2023, 24 were included in the [177Lu]Lu-PSMA-X treated group and 17 in the taxane treated group. Our findings show that [177Lu]Lu-PSMA-X RLT yielded comparable PSA50 responses in taxane-naïve patients versus those receiving taxane chemotherapy, despite considerable study heterogeneity. Notably, the taxane-naïve group had more extensive pretreatment.

CONCLUSIONS

This meta-analysis combines the largest cohorts of taxane-naïve mCRPC patients treated with [177Lu]Lu-PSMA-X RLT and taxane-treated mCRPC. It underscores similar PSA50 response rates in both groups, suggesting a potential role for [177Lu]Lu-PSMA-X RLT in taxane-naïve patients who cannot or choose not to undergo chemotherapy.

Cardiovascular risks of androgen receptor targeted agents in prostate cancer: a systematic review and meta-analysis

INTRODUCTION

Androgen receptor targeted agents (ARTA) have increasingly been incorporated into treatment regimens for various stages of prostate cancer. Patients are living longer with prostate cancer, and thus have a higher cumulative exposure to the treatment and its accompanying side effects, especially those of cardiovascular disease. We aim to assess the differences in the incidence of cardiac-related adverse events after treatment of prostate cancer with ARTA versus placebo.

METHODS

Three databases were thoroughly searched for relevant articles. The PICOS model was used to frame our clinical question, with which 2 independent authors went through several rounds of screening to select the final included studies. Meta-analysis was done using the Cochran-Mantel-Haenszel Method. Quality assessment was carried out with the Cochrane Risk of Bias tool RoB 2.

RESULTS

The use of ARTA in prostate cancer increases the incidence of cardiac-related adverse events (RR: 1.56, 95% CI: 1.29-1.90, p < 0.00001), such as hypertension (RR: 1.69, 95% CI: 1.46-1.97, p < 0.00001), ischaemic heart disease (RR: 1.84, 95% CI: 1.36-2.50, p < 0.0001), and arrhythmia (RR: 1.38, 95% CI: 1.11-1.71, p = 0.004), although this did not manifest in an increased incidence of cardiac arrests/deaths (RR: 1.28, 95% CI: 0.87-1.88, p = 0.21).

DISCUSSION

ARTA increases the risk of cardiac-related adverse events, hypertension, ischaemic heart disease and arrhythmia. Armed with this knowledge, we will be better poised to manage cardiac risks accordingly and involve a cardiologist as required when starting patients on ARTA.

Systemic Therapies for Metastatic Castration-Resistant Prostate Cancer: An Updated Review

The introduction of novel therapeutic agents for advanced prostate cancer has led to a wide range of treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC). In the past decade, new treatment options for mCRPC, including abiraterone, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T, radium-223, 177Lu-PSMA-617, and Olaparib, have demonstrated a survival benefit in phase 3 trials. Bone-modifying agents have become part of the overall treatment strategy for mCRPC, in which denosumab and zoledronic acid reduce skeletal-related events. Recently, androgen receptor-signaling inhibitors (ARSIs) and docetaxel have been used upfront against metastatic castration-sensitive prostate cancer. Further, triplet therapy with ARSI, docetaxel, and androgen deprivation therapy is emerging. However, cross-resistance may occur between these treatments, and the optimal treatment sequence must be considered. The sequential administration of ARSIs, such as abiraterone and enzalutamide, is associated with limited efficacy; however, cabazitaxel is effective for patients with mCRPC who were previously treated with docetaxel and had disease progression during treatment with ARSI. Radioligand therapy with 177Lu-PSMA-617 is a new effective class of therapy for patients with advanced PSMA-positive mCRPC. Tumors with gene alterations that affect homologous recombination repair, such as BRCA1 and BRCA2 alterations, are sensitive to poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors in mCRPC. This review sought to highlight recent advances in systemic therapy for mCRPC and strategies to support patient selection and treatment sequencing.

Prostate cancer and novel pharmacological treatment options-what's new for 2022?

INTRODUCTION

Androgen deprivation therapy (ADT) plus Androgen Receptor Target Agents (ARTAs) or docetaxel are the actual standard of care in prostate cancer (PC). Several therapeutic options are available for pretreated patients: cabazitaxel, olaparib, and rucaparib for BRCA mutations, Radium-223 for selected patients with symptomatic bone metastasis, sipuleucel T, and 177 LuPSMA-617.

AREAS COVERED

This review the new potential therapeutic approaches and the most impacting recent published trials to provide an overview on the future management of PC.

EXPERT OPINION

Currently, there is a growing interest in the potential role of triplet therapies encompassing ADT, chemotherapy, and ARTAs. These strategies, explored in different settings, appeared to be particularly promising in metastatic hormone-sensitive PC. Recent trials investigating ARTAs plus poly(adenosine diphosphate-ribose) polymerase (PARPi) inhibitor provided helpful insights for patients with metastatic castration resistant disease, regardless of homologous recombination genes status. Otherwise, the publication of the complete data is awaited, and more evidence is required. In advanced settings, several combination approaches are under investigation, to date with contradictory results, such as immunotherapy plus PARPi or chemotherapy. The radionuclide ¹⁷⁷Lu-PSMA-617 proved successful outcomes in pretreated mCRPC patients. Additional studies will better clarify the appropriate candidates to each strategy and the correct treatments' sequence.

Distinct mechanisms mediating therapy-induced cellular senescence in prostate cancer

BACKGROUND

Prostate cancer (PCa) is an age-related malignancy in men with a high incidence rate. PCa treatments face many obstacles due to cancer cell resistance and many bypassing mechanisms to escape therapy. According to the intricacy of PCa, many standard therapies are being used depending on PCa stages including radical prostatectomy, radiation therapy, androgen receptor (AR) targeted therapy (androgen deprivation therapy, supraphysiological androgen, and AR antagonists) and chemotherapy. Most of the aforementioned therapies have been implicated to induce cellular senescence. Cellular senescence is defined as a stable cell cycle arrest in the G1 phase and is one of the mechanisms that prevent cancer proliferation.

RESULTS

In this review, we provide and analyze different mechanisms of therapy-induced senescence (TIS) in PCa and their effects on the tumor. Interestingly, it seems that different molecular pathways are used by cancer cells for TIS. Understanding the complexity and underlying mechanisms of cellular senescence is very critical due to its role in tumorigenesis. The most prevalent analyzed pathways in PCa as TIS are the p53/p21^WAF1/CIP1, the p15^INK4B/p16^INK4A/pRb/E2F/Cyclin D, the ROS/ERK, p27^Kip1/CDK/pRb, and the p27^Kip1/Skp2/C/EBP β signaling. Despite growth inhibition, senescent cells are highly metabolically active. In addition, their secretome, which is termed senescence-associated secretory phenotype (SASP), affects within the tumor microenvironment neighboring non-tumor and tumor cells and thereby may regulate the growth of tumors. Induction of cancer cell senescence is therefore a double-edged sword that can lead to reduced or enhanced tumor growth.

CONCLUSION

Thus, dependent on the type of senescence inducer and the specific senescence-induced cellular pathway, it is useful to develop pathway-specific senolytic compounds to specifically targeting senescent cells in order to evict senescent cells and thereby to reduce SASP side effects.

Continuous enzalutamide after progression of metastatic castration-resistant prostate cancer treated with docetaxel (PRESIDE): an international, randomised, phase 3b study

BACKGROUND

Although androgen deprivation therapy is typically given long-term for men with metastatic prostate cancer, second-generation hormone therapies are generally discontinued before the subsequent line of treatment. We aimed to evaluate the efficacy of continuing enzalutamide after progression in controlling metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel and prednisolone.

METHODS

PRESIDE was a two-period, multinational, double-blind, randomised, placebo-controlled, phase 3b study done at 123 sites in Europe (in Austria, Belgium, Czech Republic, France, Germany, Greece, Italy, Netherlands, Norway, Poland, Russia, Spain, Sweden, Switzerland, Turkey, and the UK). Patients were eligible for period 1 (P1) of the study if they had histologically confirmed prostate adenocarcinoma without neuroendocrine differentiation or small-cell features, serum testosterone concentrations of 1·73 nmol/L or less, and had progressed during androgen deprivation therapy with a luteinising hormone-releasing hormone agonist or antagonist or after bilateral orchiectomy. In P1, patients received open-label enzalutamide 160 mg per day orally. At week 13, patients were assessed for either radiographic or prostate-specific antigen (PSA) progression (25% or more increase and 2 ng/mL or more above nadir). Patients who showed any decline in PSA at week 13 and subsequently progressed (radiographic progression, PSA progression, or both) were screened and enrolled in period 2 (P2), during which eligible patients were treated with up to ten cycles of intravenous docetaxel 75 mg/m² every 3 weeks and oral prednisolone 10 mg/day, and randomly assigned (1:1) to oral enzalutamide 160 mg/day or oral placebo. Patients were stratified by type of disease progression. The block size was four and the overall number of blocks was 400. Patients, investigators, and study organisers were masked to treatment assignment. The primary endpoint was progression-free survival analysed in all patients in P2. This trial is registered with ClinicalTrials.gov, NCT02288247, and is no longer recruiting.

FINDINGS

Between Dec 1, 2014, and Feb 15, 2016, 816 patients were screened for P1 of the study. 688 patients were enrolled in P1 and 687 received open-label enzalutamide. In P2, 271 patients were randomly assigned at 73 sites to receive enzalutamide (n=136) or placebo (n=135). The data cutoff for analysis was April 30, 2020. Median progression-free survival with enzalutamide was 9·5 months (95% CI 8·3-10·9) versus 8·3 months (6·3-8·7) with placebo (hazard ratio 0·72 [95% CI 0·53-0·96]; p=0·027). The most common grade 3 treatment-emergent adverse events were neutropenia (17 [13%] of 136 patients in the enzalutamide group vs 12 [9%] of 135 patients in the placebo group) and asthenia (ten [7%] vs six [4%]). The most common grade 4 treatment-emergent adverse event in P2 was neutropenia (23 [17%] of 136 patients in the enzalutamide group vs 28 [21%] of 135 patients in the placebo group). Serious treatment-emergent adverse events were reported in 67 (49%) of 136 patients in the enzalutamide group and 52 (39%) of 135 patients in the placebo group. Two (15%) of 13 deaths in the enzalutamide group (caused by septic shock and haematuria) and one (14%) of seven deaths in the placebo group (caused by actue kidney injury) were associated with docetaxel.

INTERPRETATION

PRESIDE met its primary endpoint and showed that continuing enzalutamide with docetaxel plus androgen deprivation therapy delayed time to progression compared with docetaxel plus androgen deprivation therapy alone, supporting the hypothesis that enzalutamide maintenance could control persistent androgen-dependent clones in men with mCRPC who progress after treatment with enzalutamide alone.

FUNDING

Astellas Pharma and Pfizer.

A phase II randomised trial of abiraterone acetate plus prednisone in combination with docetaxel or docetaxel plus prednisone after disease progression to abiraterone acetate plus prednisone in patients with metastatic castration-resistant prostate cancer: The ABIDO-SOGUG trial

BACKGROUND

We aimed to compare the efficacy and safety of maintaining or withdrawing abiraterone acetate plus prednisone (AAP) in patients with metastatic castration-resistant prostate cancer who had experienced cancer progression to this treatment and were beginning a docetaxel-based therapy.

PATIENTS AND METHODS

Phase II, randomised, open-label study conducted in patients with metastatic castration-resistant prostate cancer who were asymptomatic or mildly symptomatic. After open-label treatment with AAP, patients who had experienced cancer progression to AAP were randomised to 75 mg/m² of docetaxel plus AAP or to receive 75 mg/m² of docetaxel plus 10 mg of prednisone orally daily. The primary outcome was the radiographic progression-free survival rate at 12 months as evaluated by the investigators in all randomised patients.

RESULTS

A total of 148 patients were included in open-label treatment with AAP, and of them, 94 patients were randomised to receive either docetaxel plus AAP (intervention group; n = 47) or docetaxel plus prednisone (control group; n = 47). The 12-month radiographic progression-free survival rates did not differ between the intervention group (34.9%; 95% CI 20.7-49.2) and the control group (33.9%; 95% CI 19.5-48.3). There were no significant differences in the time to radiographic progression and the overall survival between the intervention and control groups. Grade 3-5 neutropenia with the combination of docetaxel plus prednisone and AA was more frequent than with docetaxel plus prednisone (59.6% versus 27.7%).

CONCLUSION

Our results indicate that the therapeutic strategy of maintaining AAP added to docetaxel in chemotherapy-naïve patients who have experienced cancer progression to AAP treatment should not be further evaluated and should be avoided in clinical practice.

CLINICAL TRIALS

NCT02036060 https://clinicaltrials.gov/ct2/show/NCT02036060.