Evaluation of the genomic alterations in the androgen receptor gene during treatment with high-dose testosterone for metastatic castrate-resistant prostate cancer

Experience of bipolar androgen therapy (BAT) in Argentinian oncology centres

Background

Previous studies with bipolar androgen therapy (BAT) have shown clinical activity in metastatic Castration Resistant Prostate Cancer (mCRPC) as well as the potential to re-sensitise prostate cancer cells to prior androgen receptor-targeted agents. None of these studies had tested BAT after chemotherapy. In this study, we gathered real-world evidence from three centres in Argentina where BAT is being used in castration-resistant prostate cancer (CRPC), not only prior to chemotherapy but also after several lines of treatment.

Materials and methods

This retro-prospective nonrandomised multicentre cohort study included patients with mCRPC, who received BAT in different scenarios defined by the treating physician at three centres in Argentina.

Results

A total of 21 asymptomatic patients with mCRPC were included. There was a median of two lines before BAT, with nine patients (42.8%) receiving three or more lines, and 13 patients (61.9%) receiving chemotherapy previously. Previous lines included next-generation hormonal agents (NHA) in 100% (abiraterone 33.3% and enzalutamide 71.4%), chemotherapy in 61.9%, Radium-223 in 47.6% and others in 4.8%. The progression free survival (PFS) after BAT was 3.5 months (95% CI: 3.06-7.97). PSA50 response rate (RR) was 28.5% and the overall RR was 14.3%. Of the 17 patients who had disease progression, 9 had a rechallenge to NHA, achieving a 55% RR, 6 received other treatment (chemotherapy in 5 and ¹⁷⁷Lu-PSMA in 1) with a 66% RR and 2 best supportive care. The PFS2, calculated after the initiation of BAT in the 15 patients who received further therapy, was 7.93 months (95% CI: 6.73-NR). Treatment was overall well tolerated, with only two patients requiring hospitalisation and treatment interruption due to worsening pain.

Conclusion

To the authors' knowledge, this is the first publication of BAT in later lines of therapy in mCRPC. BAT showed clinical activity in this scenario. Our data supports that BAT may play a role in CRPC re-sensitisation after multiple treatment lines.

Prognostic Role of DNA Damage Response Genes Mutations and their Association With the Sensitivity of Olaparib in Prostate Cancer Patients

Objective

Evidence shows that gene mutation is a significant proportion of genetic factors associated with prostate cancer. The DNA damage response (DDR) is a signal cascade network that aims to maintain genomic integrity in cells. This comprehensive study was performed to determine the link between different DNA damage response gene mutations and prostate cancer.

Materials and methods

A systematic literature search was performed using PubMed, Web of Science, and Embase. Papers published up to February 1, 2022 were retrieved. The DDR gene mutations associated with prostate cancer were identified by referring to relevant research and review articles. Data of prostate cancer patients from multiple PCa cohorts were obtained from cBioPortal. The OR or HR and 95% CIs were calculated using both fixed-effects models (FEMs) and random-effects models (REMs).

Results

Seventy-four studies were included in this research, and the frequency of 13 DDR genes was examined. Through the analysis of 33 articles that focused on the risk estimates of DDR genes between normal people and PCa patients, DDR genes were found to be more common in prostate cancer patients (OR = 3.6293 95% CI [2.4992; 5.2705]). Also, patients in the mutated group had a worse OS and DFS outcome than those in the unmutated group (P < .05). Of the 13 DDR genes, the frequency of 9 DDR genes in prostate cancer was less than 1%, and despite differences in race, BRCA2 was the potential gene with the highest frequency (REM Frequency = .0400, 95% CI .0324 - .0541). The findings suggest that mutations in genes such as ATR, BLM, and MLH1 in PCa patients may increase the sensitivity of Olaparib, a PARP inhibitor.

Conclusion

These results demonstrate that mutation in any DDR pathway results in a poor prognosis for PCa patients. Furthermore, mutations in ATR, BLM, and MLH1 or the expression of POLR2L, PMS1, FANCE, and other genes significantly influence Olaparib sensitivity, which may be underlying therapeutic targets in the future.

Androgen receptor mutations for precision medicine in prostate cancer

Hormonal therapies including androgen deprivation therapy and androgen receptor (AR) pathway inhibitors such as abiraterone and enzalutamide have been widely used to treat advanced prostate cancer. However, treatment resistance emerges after hormonal manipulation in most prostate cancers, and it is attributable to a number of mechanisms, including AR amplification and overexpression, AR mutations, the expression of constitutively active AR variants, intra-tumor androgen synthesis, and promiscuous AR activation by other factors. Although various AR mutations have been reported in prostate cancer, specific AR mutations (L702H, W742L/C, H875Y, F877L, and T878A/S) were frequently identified after treatment resistance emerged. Intriguingly, these hot spot mutations were also revealed to change the binding affinity of ligands including steroids and antiandrogens and potentially result in altered responses to AR pathway inhibitors. Currently, precision medicine utilizing genetic and genomic data to choose suitable treatment for the patient is becoming to play an increasingly important role in clinical practice for prostate cancer management. Since clinical data between AR mutations and the efficacy of AR pathway inhibitors are accumulating, monitoring the AR mutation status is a promising approach for providing precision medicine in prostate cancer, which would be implemented through the development of clinically available testing modalities for AR mutations using liquid biopsy. However, there are few reviews on clinical significance of AR hot spot mutations in prostate cancer. Then, this review summarized the clinical landscape of AR mutations and discussed their potential implication for clinical utilization.

Response to supraphysiological testosterone is predicted by a distinct androgen receptor cistrome

The androgen receptor (AR) is a master transcription factor that regulates prostate cancer (PC) development and progression. Inhibition of AR signaling by androgen deprivation is the first-line therapy with initial efficacy for advanced and recurrent PC. Paradoxically, supraphysiological levels of testosterone (SPT) also inhibit PC progression. However, as with any therapy, not all patients show a therapeutic benefit, and responses differ widely in magnitude and duration. In this study, we evaluated whether differences in the AR cistrome before treatment can distinguish between SPT-responding (R) and -nonresponding (NR) tumors. We provide the first preclinical evidence to our knowledge that SPT-R tumors exhibit a distinct AR cistrome when compared with SPT-NR tumors, indicating a differential biological role of the AR. We applied an integrated analysis of ChIP-Seq and RNA-Seq to the pretreatment tumors and identified an SPT-R signature that distinguishes R and NR tumors. Because transcriptomes of SPT-treated clinical specimens are not available, we interrogated available castration-resistant PC (CRPC) transcriptomes and showed that the SPT-R signature is associated with improved survival and has the potential to identify patients who would respond to SPT. These findings provide an opportunity to identify the subset of patients with CRPC who would benefit from SPT therapy.

Clinical response in metastatic castration-resistant prostate cancer (mCRPC) cases treated with supra-physiological doses of testosterone: Bipolar androgen therapy

Androgen deprivation therapy is a standard of care for metastatic prostate cancer. A paradoxical approach utilizing high doses of testosterone in castration-resistant prostate cancer patients demonstrated clinical responses. Here, we report on four heavily pretreated Japanese patients (including one patient on hemodialysis) successfully treated with supra-physiological doses of testosterone.

Efficacy and safety of bipolar androgen therapy in mCRPC after progression on abiraterone or enzalutamide: A systematic review

PURPOSE

To further determine the efficacy and safety of bipolar androgen therapy (BAT) on patients with metastatic castration-resistant prostate cancer (mCRPC) after progression on abiraterone (ABI) or enzalutamide (ENZA).

MATERIALS AND METHODS

We systematically searched the Pubmed, Web of Science and ClinicalTrials.gov up to June 2021. Literature review, study selection, and data extraction were conducted by 2 reviewers. Risk of bias was assessed according to the methodology of the European Association of Urology (EAU). A systematic review and pooled analysis were performed. The primary outcomes were PSA50 after BAT and AR-targeted therapy rechallenge, objective response rate (ORR) after BAT, and AEs after BAT. The definition of PSA50 was that participants achieving a PSA decline ≥50% according to Prostate Cancer Working Group (PCWG2) criteria. The ORR determined by determined by Response Evaluation Criteria in Solid Tumors (RECIST) included patients experienced partial response (PR) or complete response (CR).

RESULTS

In a total of 74 unique records, 5 studies were eligible for inclusion. Participants who underwent BAT achieved PSA50 of 0.26 (95% CI [0.20, 0.32]) and objective response rate (ORR) of 0.32 (95% CI [0.21, 0.44]). Patients completed BAT proceeded to AR-target therapy (ABI or ENZA) achieved moderate response (PSA50 0.54, 95% CI [0.30, 0.76]). Based on our multiple subgroup analysis, type of post-BAT AR-target therapy had a strong impact on PSA50 of AR-target therapy rechallenge. Most of adverse events (AEs) were low grade.

CONCLUSIONS

The present study indicated that BAT could induce clinical responses in mCRPC patients after progression on ABI or ENZA, with an acceptable side effects profile. BAT could also be able to restore sensitivity to ABI and ENZA rechallenge in a subset of patients.

Fundamentals of liquid biopsies in metastatic prostate cancer: from characterization to stratification

PURPOSE OF REVIEW

In this review, we provide an overview of the recent developments and prospects on the applications of blood-based liquid biopsies, including circulating tumor DNA and circulating tumor cells, in metastatic prostate cancer.

RECENT FINDINGS

Guidelines and consensus statements have been formulated to standardize preanalytical conditions that affect liquid biopsy analysis. Currently, there are four FDA approved assays for the analysis of liquid biopsies and many quantitative and qualitative assays are being developed. Comprehensive analyses of cell-free tumor DNA (ctDNA) and circulating tumor cells (CTCs) demonstrate that they adequately reflect the genomic makeup of the tumor and may thus complement or even replace tumor biopsies. The assessment of genomic aberrations in ctDNA can potentially predict therapy response and detect mechanisms of resistance. CTC count is not only a strong prognosticator in metastatic prostate cancer but can also measure therapy response.

SUMMARY

Liquid biopsies may provide a temporal snapshot of the biologic variables that affect tumor growth and progression in metastatic prostate cancer. Liquid biopsies could inform on prognostic, predictive, and response measures. However, prospective clinical trials need to be performed to provide definitive validation of the clinical value of the most advanced assays.