Olaparib plus abiraterone versus placebo plus abiraterone in metastatic castration-resistant prostate cancer (PROpel): final prespecified overall survival results of a randomised, double-blind, phase 3 trial

Hormonal Agents in Localized and Advanced Prostate Cancer: Current Use and Future Perspectives

Prostate cancer (PC) is generally a hormone-dependent tumor. Androgen deprivation therapy ( has been the standard of care in metastatic disease for more than 80 years. Subsequent studies have highlighted the efficacy of ADT even in earlier disease settings such as in localized disease or in the case of biochemical recurrence (BCR). Improved knowledge of PC biology and ADT resistance mechanisms have led to the development of novel generation androgen receptor pathway inhibitors (ARPI). Initially used only in patients who became resistant to ADT, ARPI have subsequently shown to be effective when used in patients with metastatic hormone-naive disease and in recent years their effectiveness has also been evaluated in localized disease and in case of BCR. The objective of this review is to describe the current role of agents interfering with the androgen receptor in different stages of PC and to point out future perspectives.

Strategies for the prevention or reversal of PARP inhibitor resistance

INTRODUCTION

Advances in our understanding of tumor biology shed light on hallmarks of cancer development and progression that include dysregulated DNA damage repair (DDR) machinery. Leveraging the underlying tumor genomic instability and tumor-specific defects in DDR, Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induced DNA damage emerges as a novel non-chemotherapy therapeutic opportunity. PARPis are currently approved in multiple tumor types, with the largest benefit seen in tumors with homologous recombination repair (HRR) deficiency, including germline and somatic mutations in BRCA1/2 genes (BRCA) and other pathway members such as PALB2 and Rad51c.

AREAS COVERED

This review article summarizes the current approval landscape and known and proposed mechanisms of resistance to PARPi. Further, therapeutic strategies to overcome PARPi resistance are discussed, including ongoing clinical trials.

EXPERT OPINION

PARPi have proven to be a safe and effective therapy and represents a cornerstone treatment across multiple solid tumor types. Elucidating innate and acquired mechanisms of resistance, coupled with the emergence of novel therapeutic options to capitalize on the activity of PARPi and prevent or reverse the acquisition of resistance, provides an opportunity to further expand the role of PARPi in cancer therapy.

Prostate Cancer Therapy Cardiotoxicity Map (PROXMAP) for Advanced Disease States: A Systematic Review and Network Meta-analysis with Bayesian Modeling of Treatment Histories

BACKGROUND AND OBJECTIVE

Recommendations of first-line therapies for metastatic hormone-sensitive (mHSPC), nonmetastatic castrate-resistant (M0CRPC), and metastatic castrate-resistant (mCRPC) prostate cancer do not account for cardiotoxicity due to a lack of clear prior evidence. This manuscript assesses cardiotoxicity of these therapies.

METHODS

We searched Ovid Medline, Elsevier Embase, and the Cochrane Library for randomized clinical trials (RCTs) from database inception to January 14, 2024. Network meta-analyses of first-line mHSPC, M0CRPC, and mCRPC therapies were constructed for the five cardiotoxicity metrics defined by the International Cardio-Oncology Society: heart failure, myocarditis, vascular toxicity, hypertension, and arrhythmias. Additional Bayesian network meta-analyses also accounted for prior treatment history.

KEY FINDINGS AND LIMITATIONS

Thirteen RCTs (16 292 patients) were included. For mHSPC, androgen deprivation therapy (ADT) plus docetaxel (DTX) plus abiraterone acetate (AA) with prednisone (P) demonstrated a significant increase in hypertension and arrhythmias versus ADT + DTX (risk ratio [RR] 2.85, 95% confidence interval [CI] 1.67-4.89, and RR 2.01, 95% CI 1.17-3.44, respectively); however, no corresponding differences were observed between ADT + DTX plus darolutamide (DAR) and ADT + DTX (RR 1.55, 95% CI 0.73-3.30, and RR 0.94, 95% CI 0.63-1.40, respectively). For mCRPC assuming a history of mHSPC treatment, ADT + AA + P plus olaparib (OLA) demonstrated a statistically significant decrease in hypertension versus ADT + AA + P (RR 0.20, 95% CI 0.16-0.26). M0CRPC results were unremarkable.

CONCLUSIONS AND CLINICAL IMPLICATIONS

For mHSPC, ADT + DTX + DAR demonstrates less cardiotoxicity than ADT + DTX + AA + P due to a lower risk of hypertension and arrhythmias from decreased mineralocorticoid excess. In addition, OLA counterintuitively offers decreased hypertension when superimposed on ADT + AA + P for mCRPC treatment after prior androgen deprivation from mHSPC therapy.

Durable benefit from poly(ADP-ribose) polymerase inhibitors in metastatic prostate cancer in routine practice: biomarker associations and implications for optimal clinical next-generation sequencing testing

BACKGROUND

Controlled trials have consistently demonstrated the efficacy of poly(ADP-ribose) polymerase inhibitors (PARPis) in patients with metastatic castration-resistant prostate cancer (mCRPC) and BRCA1 or BRCA2 alterations (BRCAalt). However, the reported efficacy of PARPi for alterations in other homologous recombination repair (HRR) genes is less consistent. We sought to evaluate the routine practice effectiveness of PARPi between and within these groups.

DESIGN

Patient-level data from a deidentified nationwide (USA-based) cancer clinico-genomic database between January 2011 and September 2023 were extracted. Patients with mCRPC and comprehensive genomic profiling by liquid biopsy [circulating tumor DNA (ctDNA)] or tissue (tumor) biopsy and who received single-agent PARPi were included and grouped by BRCAalt, ATMalt, other HRR, or no HRR. We further subcategorized BRCAalt into homozygous loss (BRCAloss) and all other deleterious BRCAalt (otherBRCAalt).

RESULTS

A total of 445 patients met inclusion criteria: 214 with tumor and 231 with ctDNA. BRCAalt had more favorable outcomes to PARPi compared with ATM, other HRR, and no HRR groups. Within the BRCAalt subgroup, compared with other BRCAalt, BRCAloss had a more favorable time to next treatment (median 9 versus 19.4 months, P = 0.005), time to treatment discontinuation (median 8 versus 14 months, P = 0.006), and routine practice overall survival (median 14.7 versus 19.4 months, P = 0.016). Tumor BRCAloss prevalence (3.1%) was similar to ctDNA prevalence in liquid biopsy specimens with high tumor fraction (>20%). BRCAloss was not detected in orthogonal germline testing.

CONCLUSIONS

PARPi routine practice effectiveness between groups mirrors prospective trials. Within the BRCAalt group, BRCAloss had the best outcomes. Unless the ctDNA tumor fraction is very high, somatic tissue testing (archival or metastatic) should be prioritized to identify patients who may benefit most from PARPi. When tissue testing is not clinically feasible, sufficient ctDNA tumor fraction levels for detection are enriched at clinical timepoints associated with tumor progression.

A panel-based mutational signature of homologous recombination deficiency associates with response to PARP inhibition in metastatic castration-resistant prostate cancer

BACKGROUND

The PARP inhibitor (PARPi) olaparib is approved for homologous recombination repair (HRR) gene-altered metastatic castration-resistant prostate cancer (mCRPC). However, there is significant heterogeneity in response to PARPi in patients with mCRPC. Better clinical biomarkers are needed to identify patients likely to benefit from PARPi.

METHODS

Patients with prostate adenocarcinoma and panel sequencing at Dana-Farber Cancer Institute were identified. Mutational signature analysis was performed using SigMA to characterize tumors as HRR deficient (HRD). The validity of SigMA to identify patients likely to benefit from olaparib was compared to the current FDA label (presence of a deleterious alteration in one of 14 HRR genes).

RESULTS

546 patients were identified, of which 34% were HRD. Among patients with HRR gene alterations, only patients with BRCA2 two-copy loss (2CL) were more likely to be HRD compared to patients without HRR gene alterations (74% vs 31%; P = 9.1 × 10-7). 28 patients with mCRPC received olaparib, of which 13 were HRD and 9 had BRCA2 2CL. SigMA improved upon the current FDA label for predicting PSA50 (sensitivity: 100% vs 90%; specificity: 83% vs 44%; PPV: 77% vs 47%; NPV: 100% vs 89%) and rPFS > 6 months (sensitivity: both 92%; specificity: 93% vs 53%; PPV: 92% vs 63%; NPV: 93% vs 89%). On multivariate analysis, incorporating prognostic clinical factors and HR gene alterations, SigMA-predicted HRD independently associated with improved PSA-PFS (HR = 0.086, p = 0.00082) and rPFS (HR = 0.078, p = 0.0070).

CONCLUSIONS

SigMA-predicted HRD may better identify patients likely to benefit from olaparib as compared to the current FDA label. Larger studies are needed for further validation.

TRIUMPH: phase II trial of rucaparib monotherapy in patients with metastatic hormone-sensitive prostate cancer harboring germline homologous recombination repair gene mutations

BACKGROUND

The activity of PARP inhibitors (PARPi) in patients with homologous recombination repair (HRR) mutations and metastatic castration-resistant prostate cancer has been established. We hypothesized that the benefit of PARPi can be maintained in the absence of androgen deprivation therapy (ADT) in an HRR-mutated population. We report the results of a phase II clinical trial of rucaparib monotherapy in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

METHODS

This was a multi-center, single-arm phase II trial (NCT03413995) for patients with asymptomatic, mHSPC. Patients were required to have a pathogenic germline mutation in an HRR gene for eligibility. All patients received rucaparib 600 mg by mouth twice daily, without androgen deprivation. The primary endpoint was a confirmed PSA50 response rate.

RESULTS

Twelve patients were enrolled, 7 with a BRCA1/2 mutation and 5 with a CHEK2 mutation. The confirmed PSA50 response rate to rucaparib was 41.7% (N = 5/12, 95% CI: 15.2-72.3%, one-sided P = .81 against the 50% null), which did not meet the pre-specified efficacy boundary to enroll additional patients. In patients with measurable disease, the objective response rate was 60% (N = 3/5), all with a BRCA2 mutation. The median radiographic progression-free survival on rucaparib was estimated at 12.0 months (95% CI: 8.0-NR months). The majority of adverse events were grade ≤2, and expected.

CONCLUSION

Rucaparib can induce clinical responses in a biomarker-selected metastatic prostate cancer population without concurrent ADT. However, the pre-specified efficacy threshold was not met, and enrolment was truncated. Although durable responses were observed in a subset of patients, further study of PARPi treatment without ADT in mHSPC is unlikely to change clinical practice.

PARP Inhibitor Addition to Androgen Receptor Pathway Inhibitors in Metastatic Castration-resistant Prostate Cancer Should Be Limited to BRCA Mutation Carriers

For patients with metastatic castration-resistant prostate cancer whose tumors harbor BRCA1/2 alterations, the potential benefits of combining a PARP inhibitor and an androgen receptor pathway inhibitor for first-line treatment outweigh the potential side effects. Further research is required to identify patients without detectable BRCA1/2 defects who would benefit from this approach.

Current issues and management consensus of advanced prostate cancer: Report of the Advanced Prostate Cancer Consensus Conference-JAPAN 2023

OBJECTIVE

To evaluate and compare the voting results of Japanese urologists with the global panel at the Advanced Prostate Cancer Consensus Conference (APCCC) 2022.

METHODS

Among the 198 questions discussed at the APCCC 2022, the APCCC-JAPAN 2023 focused on 14 key questions related to the management of advanced prostate cancer with insufficient high-level evidence based on their relevance to the Japanese cohort. A panel of six prostate cancer experts addressed these 14 questions and presented the latest evidence to Japanese urologists who voted on-site using a web-based system. The results were compared with those of APCCC 2022.

RESULTS

This study found significant differences in the voting results between Japanese urologists and the global panel regarding several crucial issues related to advanced prostate cancer management. These differences were those observed in treatment preferences, monitoring strategies, and treatment choices in specific clinical scenarios. These findings highlight the need for a nuanced approach tailored to the unique challenges with considerations of the Japanese healthcare environment.

CONCLUSIONS

APCCC-JAPAN 2023 provides valuable insights into the current clinical issues surrounding the management of advanced prostate cancer in Japan. The partial divergence in the consensus between Japanese urologists and the global panel underscores the importance of a context-specific approach. The results of this study provide practical guidance for physicians facing complex challenges and should be used to inform decision-making in the management of advanced prostate cancer.

BRCA1, BRCA2, and Associated Cancer Risks and Management for Male Patients: A Review

Importance

Half of all carriers of inherited cancer-predisposing variants in BRCA1 and BRCA2 are male, but the implications for their health are underrecognized compared to female individuals. Germline variants in BRCA1 and BRCA2 (also known as pathogenic or likely pathogenic variants, referred to here as BRCA1/2 PVs) are well known to significantly increase the risk of breast and ovarian cancers in female carriers, and knowledge of BRCA1/2 PVs informs established cancer screening and options for risk reduction. While risks to male carriers of BRCA1/2 PVs are less characterized, there is convincing evidence of increased risk for prostate cancer, pancreatic cancer, and breast cancer in males. There has also been a rapid expansion of US Food and Drug Administration-approved targeted cancer therapies, including poly ADP ribose polymerase (PARP) inhibitors, for breast, pancreatic, and prostate cancers associated with BRCA1/2 PVs.

Observations

This narrative review summarized the data that inform cancer risks, targeted cancer therapy options, and guidelines for early cancer detection. It also highlighted areas of emerging research and clinical trial opportunities for male BRCA1/2 PV carriers. These developments, along with the continued relevance to family cancer risk and reproductive options, have informed changes to guideline recommendations for genetic testing and strengthened the case for increased genetic testing for males.

Conclusions and Relevance

Despite increasing clinical actionability for male carriers of BRCA1/2 PVs, far fewer males than female individuals undergo cancer genetic testing. Oncologists, internists, and primary care clinicians should be vigilant about offering appropriate genetic testing to males. Identifying more male carriers of BRCA1/2 PVs will maximize opportunities for cancer early detection, targeted risk management, and cancer treatment for males, along with facilitating opportunities for risk reduction and prevention in their family members, thereby decreasing the burden of hereditary cancer.

Neurological toxicities with poly (ADP-ribose) polymerase inhibitors in cancer patients: a systematic review and meta-analysis

We conducted this meta-analysis to investigate neurological toxicities with poly (ADP-ribose) polymerase inhibitors (PARPis) in cancer patients. Databases were searched for randomized controlled trials (RCTs) from 1 January 2000 to 1 November 2023. Forty-six RCTs and 9529 patients were included. PARPis could increase the risk of all-grade headache [risk ratio (RR), 1.22; 95% confidence intervals (CI), 1.14-1.30; P < 0.00001], dizziness (RR, 1.40; 95% CI, 1.28-1.53; P < 0.00001), dysgeusia (RR, 1.93; 95% CI, 1.44-2.60; P < 0.0001) and insomnia (RR, 1.32; 95% CI, 1.09-1.60; P < 0.0001) in cancer patients. Headache was the most common neurological toxicity. Niraparib was associated with a higher risk of headache and insomnia, talazoparib with a higher risk of dizziness and rucaparib with a higher risk of dysgeusia. Breast cancer patients receiving PARPis have a higher risk of dysgeusia, while ovarian cancer patients are at an increased risk of insomnia. PARPis may increase the risk of mild to moderate neurological toxicities, but not severe ones.

Real-world data on the prevalence of BRCA1/2 and HRR gene mutations in patients with primary and metastatic castration resistant prostate cancer

PURPOSE

This study seeks to contribute real-world data on the prevalence of BRCA1/2 and HRR gene mutations in prostate cancer.

METHODS

We compiled sequencing data of 197 cases of primary and metastatic prostate cancer, in which HRR mutation analysis was performed upon clinical request within the last 5 years. All cases were analyzed using a targeted NGS BRCAness multigene panel, including 8 HRR genes (ATM, BRCA1, BRCA2, CDK12, CHEK2, FANCA, HDAC2, PALB2).

RESULTS

Our findings reveal a prevalence of potentially targetable mutations based on FDA criteria of 20.8%, which is comparable to the literature. However, the frequency of targetable BRCA2 mutations within our cohort was lower than reported for mCRPC and ATM and CHEK2 mutations were more prevalent instead. Thus, while 20.8% (n = 38) of the cases meet the criteria for olaparib treatment per FDA approval, only 4.9% (n = 9) align with the eligibility criteria according to the EMA approval.

CONCLUSION

This study offers valuable real-world insights into the landscape of BRCA1/2 and HRR gene mutations and the practical clinical management of HRR gene testing in prostate cancer, contributing to a better understanding of patient eligibility for PARPi treatment.

Olaparib monotherapy or in combination with abiraterone for treating mutated metastatic castration-resistant prostate cancer: alone or stronger together?

INTRODUCTION

Prostate cancer has entered the era of precision medicine with the introduction of PARP inhibitors for patients with specific mutations in genes associated with DNA damage repair. Recent studies have shown benefit in combination therapy with PARP inhibitors like olaparib and antiandrogens like abiraterone.

AREAS COVERED

This review discusses the pharmacodynamics and pharmacokinetics of olaparib as well as the data supporting combination therapy with olaparib and abiraterone.

EXPERT OPINION

Co-targeting the androgen receptor and PARP pathway has shown clear clinical benefit in the management of patients with metastatic castration resistant prostate cancer and mutations in BRCA1, BRCA2, and ATM. The benefit in patients without these mutations is less clear, and the benefit of olaparib combination therapy in the management of hormone sensitive disease remains to be seen.

Should Only Patients with BRCA Mutation Be Treated with a Combination of an Androgen Receptor Pathway Inhibitor and a PARP Inhibitor for Metastatic Castration-resistant Prostate Cancer? The Answer Is No

Patients who benefit the most from combinations of an androgen receptor pathway inhibitor and a PARP inhibitor are those with a BRCA mutation, but there are certainly patients without BRCA mutations who will benefit from this treatment strategy.

DNA damage-mediated FTO downregulation promotes CRPC progression by inhibiting FOXO3a via an m6A-dependent mechanism

Polyadenosine diphosphate-ribose polymerase inhibitors (PARPi) represent a promising novel treatment for castration-resistant prostate cancer (CRPC) with encouraging results. However, the combination targets in CRPC remain largely unexplored. N6-methyladenosine (m6A) has been shown to play a crucial role in cancer progression and DNA damage response. Here, we observed a higher overall level of m6A and a downregulation of Fat mass and obesity-associated protein (FTO), which correlated with unfavorable clinicopathological parameters in prostate cancer (PCa). Functionally, reduced FTO promotes PCa growth, while overexpression of FTO has the opposite effect. Mechanistically, FOXO3a was identified as the downstream target of FTO in PCa. FTO downregulates the expression of FOXO3a in an m6A-dependent manner, leading to the degradation of its mRNA. Importantly, DNA damage can degrade FTO through the ubiquitination pathway. Finally, we found that overexpression of FTO can enhance the effect of PARPi on PCa. Therefore, our findings may provide insight into novel therapeutic approaches for CRPC.

Genetics of prostate cancer: a review of latest evidence

Prostate cancer (PrCa) is a largely heritable and polygenic disease. It is the most common cancer in people with prostates (PwPs) in Europe and the USA, including in PwPs of African descent. In the UK in 2020, 52% of all cancers were diagnosed at stage I or II. The National Health Service (NHS) long-term plan is to increase this to 75% by 2028, to reduce absolute incidence of late-stage disease. In the absence of a UK PrCa screening programme, we should explore how to identify those at increased risk of clinically significant PrCa.Incorporating genomics into the PrCa screening, diagnostic and treatment pathway has huge potential for transforming patient care. Genomics can increase efficiency of PrCa screening by focusing on those with genetic predisposition to cancer-which when combined with risk factors such as age and ethnicity, can be used for risk stratification in risk-based screening (RBS) programmes. The goal of RBS is to facilitate early diagnosis of clinically significant PrCa and reduce overdiagnosis/overtreatment in those unlikely to experience PrCa-related symptoms in their lifetime. Genetic testing can guide PrCa management, by identifying those at risk of lethal PrCa and enabling access to novel targeted therapies.PrCa is curable if diagnosed below stage III when most people do not experience symptoms. RBS using genetic profiling could be key here if we could show better survival outcomes (or reduction in cancer-specific mortality accounting for lead-time bias), in addition to more cost efficiency than age-based screening alone. Furthermore, PrCa outcomes in underserved communities could be optimised if genetic testing was accessible, minimising health disparities.

Treatment Patterns and Survival Outcomes Among Androgen Receptor Pathway Inhibitor-Experienced Patients With Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

There is limited real-world data regarding subsequent treatment utilization and clinical outcomes following initial androgen receptor pathway inhibitor (ARPI) exposure for the treatment of advanced prostate cancer. This study aimed to address this evidence gap.

METHODS

Electronic health records during 01/01/2013-07/31/2022 from Flatiron Health were used to identify adults with mCRPC, who had prior exposure to ARPIs (irrespective of the setting) and ≥1 post-ARPI line of therapy (LOT) in the mCRPC setting (index therapy: the first eligible LOT in the mCRPC setting). Treatment patterns and survival outcomes following the initiation of index therapy were reported.

RESULTS

Among 804 ARPI-experienced mCRPC patients, 459 patients (57.1%) received another ARPI as their index therapy and 192 (23.9%) received chemotherapy as their index therapy. In the overall population, median time on the index therapy and median time from index therapy to next therapy were 4.1 and 6.2 months, respectively. Median overall survival and radiographic progression-free survival from the initiation of index therapy were 15.1 and 7.0 months, respectively.

CONCLUSIONS

In this real-world analysis, more than half of patients attempted at least 1 additional ARPI in the mCRPC setting, despite prior treatment with ARPIs. The short treatment duration and survival time highlight the unmet need for additional, effective therapies that may improve clinical outcomes in this population.

EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer. Part II-2024 Update: Treatment of Relapsing and Metastatic Prostate Cancer

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy and Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Urological Pathology (ISUP)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (PCa) have been updated. Here we provide a summary of the 2024 guidelines.

METHODS

The panel performed a literature review of new data, covering the time frame between 2020 and 2023. The guidelines were updated and a strength rating for each recommendation was added on the basis of a systematic review of the evidence.

KEY FINDINGS AND LIMITATIONS

Risk stratification for relapsing PCa after primary therapy may guide salvage therapy decisions. New treatment options, such as androgen receptor-targeted agents (ARTAs), ARTA + chemotherapy combinations, PARP inhibitors and their combinations, and prostate-specific membrane antigen-based therapy have become available for men with metastatic PCa.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Evidence for relapsing, metastatic, and castration-resistant PCa is evolving rapidly. These guidelines reflect the multidisciplinary nature of PCa management. The full version is available online (http://uroweb.org/guideline/ prostate-cancer/).

PATIENT SUMMARY

This article summarises the 2024 guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are based on evidence and guide doctors in discussing treatment decisions with their patients. The guidelines are updated every year.

Novel insights into RB1 in prostate cancer lineage plasticity and drug resistance

Prostate cancer is the second most common malignancy among men in the world, posing a serious threat to men's health and lives. RB1 is the first human tumor suppressor gene to be described, and it is closely associated with the development, progression, and suppression of a variety of tumors. It was found that the loss of RB1 is an early event in prostate cancer development and is closely related to prostate cancer development, progression and treatment resistance. This paper reviews the current status of research on the relationship between RB1 and prostate cancer from three aspects: RB1 and prostate cell lineage plasticity; biological behavior; and therapeutic resistance. Providing a novel perspective for developing new therapeutic strategies for RB1-loss prostate cancer.

Highlights from the 2024 ASCO Genitourinary Symposium: focus on urothelial and prostate cancer

The 2024 ASCO Genitourinary Cancer Symposium, this year celebrating the 20th anniversary, delved into key advancements in urothelial carcinoma (UC) and prostate cancer (PC). For UC, insights emerged from adjuvant pembrolizumab for muscle-invasive urothelial carcinoma, and from the efficacy of the EV-302 study of enfortumab vedotin +pembrolizumab in the metastatic setting. In PC, adjuvant therapy with high-dose radiotherapy schedules plus long-t erm ADT was explored. In metastatic castration-resistant PC, highlights included a novel combo (cabozantinib+atezolizumab) for poor prognosis patients; confirmed benefits of ARSI+PARPi in BRCA-mutated patients; and safety considerations for ARSI treatments. The symposium continued its role as an indispensable platform for shaping specialized oncological care.

Treatment patterns and outcomes in patients with nonmetastatic castration-resistant prostate cancer in the United States

Aim: Androgen receptor pathway inhibitors (ARPIs) prolong metastasis-free survival and overall survival in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC). This study aimed to evaluate real-world treatment patterns, utilization and survival outcomes in patients with nmCRPC. Patients & methods: This retrospective cohort study used Optum database electronic health records of patients with nmCRPC from 1 January 2007 to 31 December 2020 in the US. Results: Of 1955 patients, >80% received androgen-deprivation therapy (ADT) alone or ADT + first-generation nonsteroidal antiandrogen (NSAA) as first-line treatment, while only 8.24% received ADT + ARPI. ADT + ARPI remained underutilized even among those with high-risk nmCRPC. Further, ADT + NSAA had no survival benefit compared with ADT alone. Conclusion: Practice-improvement strategies are needed for treatment intensification with ARPIs for patients with nmCRPC.

Combination of PARP Inhibitors and Androgen Receptor Pathway Inhibitors in Metastatic Castration-Resistant Prostate Cancer

Despite recent advances in the treatment of metastatic prostate cancer, progression to a castration-resistant state remains inevitable for most and prognosis is limited. Genetic testing for homologous recombination repair pathway alterations is recommended for all patients with advanced prostate cancer given that a mutation is present in up to 25% of cases. Poly(ADP-ribose) polymerase (PARPis) are now approved for use in patients with metastatic castration-resistant prostate cancer who have progressed on an androgen receptor pathway inhibitor (ARPI) and harbour a germline or somatic homologous recombination repair mutation. Preclinical data support a synergistic effect with an ARPI and PARPi, and various ARPI-PARPi combinations have therefore been explored in phase III clinical trials. Despite heterogeneous findings, a clear hierarchy of benefit is evident, with patients harbouring a BRCA mutation deriving the greatest magnitude of benefit, followed by any homologous recombination repair mutation. The benefit in homologous recombination repair-proficient cohort is less clear, and questions remain about whether ARPI-PARPi combination therapy should be offered to patients without a homologous recombination repair mutation. With ARPIs now considered standard-of-care for metastatic hormone-sensitive prostate cancer, ARPI-PARPi combination therapy is currently being explored earlier in the treatment paradigm. The purpose of this review is to discuss the rationale behind ARPI-PARPi combination therapy, summarise the results of key clinical trials, and discuss clinical considerations and future perspectives.

Acute BRCAness Induction and AR Signaling Blockage through CDK12/7/9 Degradation Enhances PARP Inhibitor Sensitivity in Prostate Cancer

Current treatments for advanced prostate cancer (PCa) primarily target androgen receptor (AR)-pathways. However, the emergence of castration-resistant prostate cancer (CRPC) and resistance to AR signaling inhibitors (ARSI) remains a significant clinical challenge. This study introduces BSJ-5-63, a novel triple degrader targeting cyclin-dependent kinases (CDKs) CDK12, CDK7, and CDK9, with potential to transform CRPC therapy. BSJ-5-63 effectively downregulates homologous recombination repair (HRR) genes, including BRCA1 and BRCA2, through CDK12 degradation, and attenuates AR signaling through CDK7 and CDK9 degradation, further enhancing its therapeutic impact. Importantly, BSJ-5-63 induces a "BRCAness" state that persists for a significant duration, enabling sequential combination therapy with PARP inhibitors (PARPis) while potentially minimizing drug-related toxicity and resistance. In both in vitro and in vivo studies, BSJ-5-63 exhibited potent antiproliferative effects in both AR-positive and AR-negative CRPC models. This study presents a promising multi-pronged approach for CRPC treatment, addressing both DNA repair mechanisms and AR signaling, with the potential to benefit a wide range of patients regardless of their BRCA1/2 mutational status.

SIGNIFICANCE

This study introduces BSJ-5-63, a triple degrader designed to target CDK12, CDK7, and CDK9, making a significant advancement in CRPC therapy. The distinctive mechanism of BSJ-5-63 involves downregulating HRR genes and inhibiting AR signaling, thereby inducing a BRCAness state. This enhances sensitivity to PARP inhibition, effectively addressing ARSI resistance and improving the overall efficacy of treatment. The development of BSJ-5-63 represents a promising therapeutic approach, with the potential to benefit a broad spectrum of CRPC patients.

Impact of homologous recombination repair/BReast CAncer (BRCA) gene alterations on survival in a real-world setting of metastatic prostate cancer

OBJECTIVE

To investigate alterations of homologous recombination repair (HRR) and especially BReast CAncer 1/2 (BRCA1/2) gene on overall survival (OS). Moreover, to explore the effect of inhibition of poly(ADP-ribose)-polymerase (PARPi) as systemic therapy for metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

Of all HRR-screened patients with metastatic prostate cancer, baseline characteristics were sampled. Kaplan-Meier estimates and multivariable Cox regression models predicted the effect of HRR/BRCA1/2 alterations on OS.

RESULTS

Of 196 eligible patients, 61 (31%) harboured any HRR and 40 (20%) BRCA1/2 alterations. Of HRR alterations, 40 (66%) vs six (10%) vs five (8.2%) vs four (6.6%) vs two (3.3%) vs four (6.6%) were BRCA1/2 vs Ataxia-telangiectasia mutated kinase (ATM) vs checkpoint kinase 2 (CHEK2) vs cyclin-dependent kinase 12 (CDK12) vs Fanconi anaemia complementation Group A (FANCA) vs positive for other mutations. Of these, 30% received a PARPi. OS differed significantly between HRR-positive vs -negative patients. Specifically in hormone-sensitive prostate cancer, the median OS was 63 (HRR positive) vs 57 (BRCA1/2 positive) vs 113 months (HRR negative) (P ≤ 0.01). In mCRPC, OS was 42 (HRR positive) vs 41 (BRCA1/2 positive) vs 70 months (HRR negative) (P ≤ 0.01). HRR and BRCA1/2 alterations were associated with worse OS after multivariable adjustment. Finally, patients with mCRPC with BRCA1/2 mutation treated without PARPi harboured worse OS than patients with BRCA1/2 mutation and PARPi therapy (median OS: 33 vs 48 months, P < 0.03).

CONCLUSION

Incidence of HRR alteration in a clinical real-world setting is high when using blood- and tissue-based tests. Patients with HRR/BRCA alterations have worse outcomes resulting in significant OS differences between HRR/BRCA-positive patients with mCRPC with and without PARPi usage vs HRR/BRCA-negative patients.

Safety and hematological toxicities of PARP inhibitors in patients with cancer: a systematic review of randomized controlled trials and a pharmacovigilance analysis

INTRODUCTION

This study aimed to estimate the toxicities of PARP inhibitors (PARPis), based on randomized controlled trials (RCTs) and the FDA Adverse Event Reporting System (FAERS) database.

METHODS

Four electronic databases were searched from inception to 16 April 2024, for RCTs of approved PARPis. The primary and secondary outcomes were grade 3-5 adverse events (AEs) and grade 3-5 hematological AE, respectively. We conducted network meta-analyses to calculate the relative risks (RRs) and 95% confidence intervals (CIs) of outcomes. A disproportionality analysis was conducted to estimate the signals of hematological AEs associated with PARPis from the FAERS database.

RESULTS

Overall, 27 RCTs involving 11,067 patients with cancer were included. Olaparib had the best safety profile for any grade 3-5 AEs and hematological AEs among four approved PARPis. Olaparib did not increase the risk of thrombocytopenia (RR: 1.48; 95%CI: 0.64-3.39), but other PARPis did. Furthermore 14,780 hematological AE reports associated with PARPis were identified in the FAERS database, and all PARPis were associated with strong hematological AE signals. Hematological AEs mainly occurred within the first 3 months (80.84%) after PARPi initiation.

CONCLUSION

Olaparib had the best safety profile among five PARPis. PARPi-associated hematological AEs mainly occurred within the first 3 months.

REGISTRATION

PROSPERO (CRD42022385274).

Role of Lutetium Radioligand Therapy in Prostate Cancer

Theranostics utilize ligands that chelate radionuclides and selectively bind with cancer-specific membrane antigens. In the case of prostate cancer (PCa), the state-of-the-art lutetium-177-PSMA combines the radioactive β-emitter 177Lu with Vipivotide Tetraxetan, a prostate-specific membrane antigen (PSMA)-binding ligand. Several studies have been conducted, and the therapy is not without adverse effects (e.g., xerostomia, nausea, and fatigue); however, few events are reported as severe. The available evidence supports the use of 177Lu-PSMA in selected metastatic castration-resistant prostate cancer patients, and the treatment is considered a standard of care in several clinical scenarios. Emerging research shows promising results in the setting of hormone-sensitive prostate cancer; however, evidence from high-quality controlled trials is still missing. In this review, we discuss the available evidence for the application of 177Lu-PSMA in the management of PCa patients.

Metastatic Castration-Resistant Prostate Cancer: Advances in Treatment and Symptom Management

OPINION STATEMENT

The management of metastatic castrate-resistant prostate cancer (mCRPC) has evolved in the past decade due to substantial advances in understanding the genomic landscape and biology underpinning this form of prostate cancer. The implementation of various therapeutic agents has improved overall survival but despite the promising advances in therapeutic options, mCRPC remains incurable. The focus of treatment should be not only to improve survival but also to preserve the patient's quality of life (QoL) and ameliorate cancer-related symptoms such as pain. The choice and sequence of therapy for mCRPC patients are complex and influenced by various factors, such as side effects, disease burden, treatment history, comorbidities, patient preference and, more recently, the presence of actionable genomic alterations or biomarkers. Docetaxel is the first-line treatment for chemo-naïve patients with good performance status and those who have yet to progress on docetaxel in the castration-sensitive setting. Novel androgen agents (NHAs), such as abiraterone and enzalutamide, are effective treatment options that are utilized as second-line options. These medications can be considered upfront in frail patients or patients who are NHA naïve. Current guidelines recommend genetic testing in mCRPC for mutations in DNA repair deficiency genes to inform treatment decisions, as for example in breast cancer gene mutation testing. Other potential biomarkers being investigated include phosphatase and tensin homologues and homologous recombination repair genes. Despite a growing number of studies incorporating biomarkers in their trial designs, to date, only olaparib in the PROFOUND study and lutetium-177 in the VISION trial have improved survival. This is an unmet need, and future trials should focus on biomarker-guided treatment strategies. The advent of novel noncytotoxic agents has enhanced targeted drug delivery and improved treatment responses with favourable toxicity profiling. Trials should continue to incorporate and report health-related QoL scores and functional assessments into their trial designs.

The efficacy and safety of PARP inhibitors in mCRPC with HRR mutation in second-line treatment: a systematic review and bayesian network meta-analysis

BACKGROUND

Poly (ADP- ribose) polymerase inhibitors (PARPi) has been increasingly adopted for metastatic castration-resistance prostate cancer (mCRPC) patients with homologous recombination repair deficiency (HRD). However, it is unclear which PARPi is optimal in mCRPC patients with HRD in 2nd -line setting.

METHOD

We conducted a systematic review of trials regarding PARPi- based therapies on mCRPC in 2nd -line setting and performed a Bayesian network meta-analysis (NMA). Radiographic progression-free survival (rPFS) was assessed as primary outcome. PSA response and adverse events (AEs) were evaluated as secondary outcomes. Subgroup analyses were performed according to specific genetic mutation.

RESULTS

Four RCTs comprised of 1024 patients (763 harbored homologous recombination repair (HRR) mutations) were identified for quantitative analysis. Regarding rPFS, olaparib monotherapy, rucaparib and cediranib plus olaparib showed significant improvement compared with ARAT. Olaparib plus cediranib had the highest surface under cumulative ranking curve (SUCRA) scores (87.5%) for rPFS, followed by rucaparib, olaparib and olaparib plus abiraterone acetate prednisone. For patients with BRCA 1/2 mutations, olaparib associated with the highest probability (98.1%) of improved rPFS. For patients with BRCA-2 mutations, olaparib and olaparib plus cediranib had similar efficacy. However, neither olaparib nor rucaparib showed significant superior effectiveness to androgen receptor-axis-targeted therapy (ARAT) in patients with ATM mutations. For safety, olaparib showed significantly lower ≥ 3 AE rate compared with cediranib plus olaparib (RR: 0.72, 95% CI: 0.51, 0.97), while olaparib plus cediranib was associated with the highest risk of all-grade AE.

CONCLUSION

PARPi-based therapy showed considerable efficacy for mCRPC patients with HRD in 2nd -line setting. However, patients should be treated accordingly based on their genetic background as well as the efficacy and safety of the selected regimen.

TRIAL REGISTRATION

CRD42023454079.

Thromboembolic risk in prostate cancer patients treated with PARP inhibitors: A systematic review and meta-analysis

BACKGROUND

Poly (ADP-ribose) polymerase inhibitors (PARPi) have been associated with thrombotic events, although the association with thrombosis risk in different cancers remains poorly defined.

METHODS

This meta-analysis included phase II and phase III clinical trials in which patients with metastatic prostate cancer were treated with PARPi either as monotherapy or in combination. The primary endpoints were the rates of thromboembolic events in prostate cancer patients.

RESULTS

A total of 2210 and 1662 patients with prostate cancer were compared in the PARP inhibitor and control groups, respectively. 96 (4.3 %) and 37 (2.2 %) patients had thrombosis in the PARPi and control groups, respectively. PARPi had a statistically significant increased risk of thrombosis in prostate cancer patients (Odds Ratio (OR)=1.98, 95 % CI: 1.06-3.70, P=0.030).

CONCLUSION

The heightened thrombotic risk associated with PARPi treatment in prostate cancer emphasizes the need for comprehensive management protocols to effectively reduce the risk and ensure safer outcomes.

Advancing Prostate Cancer Care: Treatment Approaches to Precision Medicine, Biomarker Innovations, and Equitable Access

Genetic testing and molecular imaging have great promise in the accurate diagnosis and treatment of #prostate #cancer, but only if they can be developed and implemented to achieve equitable benefit for all men.

PARP inhibitors in prostate cancers, is it time for combinations?

Despite several improvements in outcomes, metastatic prostate cancer remains deadly. Alterations in the homologous recombination repair (HRR) pathway are associated with more aggressive disease. Olaparib and rucaparib, two poly-ADP-ribose polymerase (PARP) inhibitors, have received approval from the authorities of several countries for their anti-tumoral effects in patients with metastatic castration-resistant prostate cancers harboring HRR gene alterations, in particular BRCA2. More recently, it has been hypothesized that new hormonal therapies (NHTs) and PARP inhibitors (PARPi) could have synergistic actions and act independently of HRR deficiency. This review proposes to discuss the advantages and disadvantages of PARPi used as monotherapy or in combination with NHTs and whether there is a need for molecular selection.

Outcomes and patterns of use of Radium-223 in metastatic castration-resistant prostate cancer

Introduction

Radium-223 dichloride (Ra-223) is recommended as a treatment option for metastatic castration-resistant prostate cancer (mCRPC) patients with symptomatic bone metastases and no visceral disease, after docetaxel failure, or in patients who are not candidates to receive it. In this study, we aimed to ambispectively analyze overall survival (OS) and prognostic features in mCRPC in patients receiving Ra-223 as per clinical routine practice and identify the most suitable treatment sequence.

Patients and methods

This study is observational, multicentric, and ambispective. Eligibility criteria included mCRPC patients treated with Ra-223, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, without visceral metastases, and no more than three cm involved lymph nodes.

Results

A total of 145 patients were included; the median age was 73.97 years, and a Gleason score of more than or equal to 7 in 61 (48%) patients; 73 (81%) had previously received docetaxel. The most important benefit was reached by those patients who received Ra-223 in the second-line setting, with a median OS of 17 months (95% CI, 12-21), and by patients who received six cycles of treatment, with a median OS of 19 months (95% CI, 14-21). An alkaline phosphatase (ALP) decrease was also identified as a prognosis marker. When performing the multivariate analysis, the time to develop castration-resistant disease longer than 24 months was the most important prognostic factor to predict the evolution of the patients receiving Ra-223. Ra-223 was well tolerated, with thrombocytopenia, anemia, and diarrhea being the main adverse events.

Conclusion

There is a benefit for those patients who received Ra-223 in the second-line setting, regardless of prior use of docetaxel. In addition, a survival benefit for patients presenting with a decline in ALP was observed.

Real-world data on the comprehensive genetic profiling test for Japanese patients with metastatic castration-resistant prostate cancer

OBJECTIVE

comprehensive genomic profiling test has been covered by Japanese health insurance since June 2019. However, no real-world data on the test have been reported with a focus on Japanese patients with prostate cancer.

METHODS

we retrospectively reviewed the data of 45 consecutive patients with metastatic castration-resistant prostate cancer, who underwent the comprehensive genomic profiling tests at Kitasato University Hospital between August 2019 and December 2022. Patients' characteristics, prevalence of gene alterations and therapeutic impact of genotype-matched therapy were assessed.

RESULTS

genomic data were obtained using a tissue-based test (n = 32) and liquid-based test (n = 13). Actionable genomic alternations were identified in 51.1% of patients, and 22.2% were treated with genotype-matched therapy. The main reason for not receiving genotype-matched therapy was disease progression, accounting for 46.2% (6/13). Kaplan-Meier analysis showed significantly longer overall survival after the comprehensive genomic profiling tests in patients with genotype-matched therapy under public insurance (17.8%, n = 8) than those without it (median: not reached vs. 18.1 months; P = 0.003). Five (62.5%) out of the eight patients with genotype-matched therapy under public insurance had BRCA1 or 2 deleterious alteration. Multivariate analyses showed that BRCA deleterious alteration (17.8%, n = 8) was an independent risk factor for shorter time to castration-resistant prostate cancer (hazard ratio: 2.46, 95% confidence interval: 1.04-5.87; P = 0.041), and no patients with the alteration had ≤5 bone metastases.

CONCLUSIONS

the results of this study showed the promising survival outcomes in patients with genotype-matched therapy under public insurance, even in the castration-resistant prostate cancer setting. Further detection of promising therapeutic target gene is expected to increase the number of patients who reach genotype-matched therapies.

Clinical Management of Advanced Prostate Cancer: Where Does Radiopharmaceutical Therapy Fit in the Treatment Algorithm?

Most men with newly appreciated metastatic prostate cancer are optimally treated with a backbone consisting of androgen receptor-directed therapy with or without taxane chemotherapy. Despite improvements in disease outcomes, prostate cancer remains an extremely heterogeneous disease with variable mechanisms of therapeutic resistance. As a result, it remains a leading cause of cancer-related death in men. Radiopharmaceutical therapy has emerged as an alternative, non-androgen receptor-directed treatment modality for metastatic castration-resistant prostate cancer that impacts patient survival and represents a potentially more personalized approach. In this review, we aim to outline the current treatment landscape for metastatic prostate cancer with a focus on radiopharmaceutical therapy, specifically 177Lu-PSMA-617. In addition, we illustrate various clinical challenges with 177Lu-PSMA-617 treatment to date and explore investigative efforts to leverage radiopharmaceutical therapies as part of combination regimens or earlier in the treatment algorithm to further improve patient outcomes. Finally, we introduce ongoing studies of alternative radiopharmaceutical therapies in metastatic prostate cancer that may be incorporated into the treatment algorithm pending further study.

First-line combination treatment with PARP and androgen receptor-signaling inhibitors in HRR-deficient mCRPC: Applying clinical study findings to clinical practice in the United States

INTRODUCTION

Metastatic castration-resistant prostate cancer (mCRPC) remains incurable and develops from biochemically recurrent PC treated with androgen deprivation therapy (ADT) following definitive therapy for localized PC, or from metastatic castration-sensitive PC (mCSPC). In the mCSPC setting, treatment intensification of ADT plus androgen receptor (AR)-signaling inhibitors (ARSIs), with or without chemotherapy, improves outcomes vs ADT alone. Despite multiple phase 3 trials demonstrating a survival benefit of treatment intensification in PC, there remains high use of ADT monotherapy in real-world clinical practice. Prior studies indicate that co-inhibition of AR and poly(ADP-ribose) polymerase (PARP) may result in enhanced benefit in treating tumors regardless of alterations in DNA damage response genes involved either directly or indirectly in homologous recombination repair (HRR). Three recent phase 3 studies evaluated the combination of a PARP inhibitor (PARPi) with an ARSI as first-line treatment for mCRPC: TALAPRO-2, talazoparib plus enzalutamide; PROpel, olaparib plus abiraterone acetate and prednisone (AAP); and MAGNITUDE, niraparib plus AAP. Results from these studies have led to the recent approval in the United States of talazoparib plus enzalutamide for the treatment of mCRPC with any HRR alteration, and of both olaparib and niraparib indicated in combination with AAP for the treatment of mCRPC with BRCA alterations.

SUMMARY

Here, we review the newly approved PARPi plus ARSI treatments within the context of the mCRPC treatment landscape, provide an overview of practical considerations for the combinations in clinical practice, highlight the importance of HRR testing, and discuss the benefits of treatment intensification for patients with mCRPC.

Highlighting recent progress in the treatment of men with advanced prostate cancer

PURPOSE OF REVIEW

This review is designed to highlight recent research efforts to optimize treatment strategies in men with advanced prostate cancer.

RECENT FINDINGS

Recent research analyses have suggested an overall survival advantage to treating some men with newly identified metastatic prostate cancer with a "triplet" of androgen deprivation therapy, docetaxel, and an androgen receptor axis-targeted agent (ARAT), but further work remains to refine which men need this aggressive of a treatment approach. Randomized trials have led to the approval of poly(ADP-ribose) polymerase inhibitor/ARAT agent combinations for some men with metastatic castration resistant prostate cancer, but the applicability of this approach to the growing number of men receiving combinations of systemic therapy in the castration-sensitive setting is unclear. Trials to refine use of prostate-specific membrane antigen (PSMA)-directed radiopharmaceuticals are ongoing, while novel treatment approaches targeting mechanisms driving advanced prostate cancer continue to be explored.

SUMMARY

Ongoing research focuses on refining the best combination and sequence of treatments for men with advanced prostate cancer. Future questions remain about use of existing therapies, and novel treatment approaches need to be developed.

Systemic therapy landscape of advanced prostate cancer

Prostate cancer is the most commonly diagnosed cancer in American men and 2nd leading cause of cancer-related deaths in the United States. Androgen deprivation therapy (ADT) is the backbone of treatment for advanced prostate cancer. Over the past several decades a number of new therapeutics, such as novel androgen receptor pathway inhibitors, targeted agents and radionuclide therapies, have been introduced for the treatment of prostate cancers. These agents have been demonstrated to improve clinical outcomes of prostate cancer patients in randomized clinical trials. In addition, new therapeutic strategies, such as early intensification of ADT, novel treatment combinations, and treatment sequencing, are expected to improve outcomes further. In this clinical review, we discuss the changing treatment landscape for advanced prostate cancer with a focus on new therapeutics.

Homologous Recombination Repair Deficiency in Metastatic Prostate Cancer: New Therapeutic Opportunities

More than 20% of metastatic prostate cancer carries genomic defects involving DNA damage repair pathways, mainly in homologous recombination repair-related genes. The recent approval of olaparib has paved the way to precision medicine for the treatment of metastatic prostate cancer with PARP inhibitors in this subset of patients, especially in the case of BRCA1 or BRCA2 pathogenic/likely pathogenic variants. In face of this new therapeutic opportunity, many issues remain unsolved. This narrative review aims to describe the relationship between homologous recombination repair deficiency and prostate cancer, the techniques used to determine homologous recombination repair status in prostate cancer, the crosstalk between homologous recombination repair and the androgen receptor pathway, the current evidence on PARP inhibitors activity in metastatic prostate cancer also in homologous recombination repair-proficient tumors, as well as emerging mechanisms of resistance to PARP inhibitors. The possibility of combination therapies including a PARP inhibitor is an attractive option, and more robust data are awaited from ongoing phase II and phase III trials outlined in this manuscript.

PARP-ish: Gaps in Molecular Understanding and Clinical Trials Targeting PARP Exacerbate Racial Disparities in Prostate Cancer

PARP is a nuclear enzyme with a major function in the DNA damage response. PARP inhibitors (PARPi) have been developed for treating tumors harboring homologous recombination repair (HRR) defects that lead to a dependency on PARP. There are currently three PARPi approved for use in advanced prostate cancer (PCa), and several others are in clinical trials for this disease. Recent clinical trial results have reported differential efficacy based on the specific PARPi utilized as well as patient race. There is a racial disparity in PCa, where African American (AA) males are twice as likely to develop and die from the disease compared to European American (EA) males. Despite the disparity, there continues to be a lack of diversity in clinical trial cohorts for PCa. In this review, PARP nuclear functions, inhibition, and clinical relevance are explored through the lens of racial differences. This review will touch on the biological variations that have been explored thus far between AA and EA males with PCa to offer rationale for investigating PARPi response in the context of race at both the basic science and the clinical development levels.

Tolerability of Olaparib Combined with Abiraterone in Patients with Metastatic Castration-resistant Prostate Cancer: Further Results from the Phase 3 PROpel Trial

BACKGROUND

The PROpel study (NCT03732820) demonstrated a statistically significant progression-free survival benefit with olaparib plus abiraterone versus placebo plus abiraterone in the first-line metastatic castration-resistant prostate cancer (mCRPC) setting, irrespective of homologous recombination repair mutation status.

OBJECTIVE

We report additional safety analyses from PROpel to increase clinical understanding of the adverse-event (AE) profiles of olaparib plus abiraterone versus placebo plus abiraterone.

DESIGN, SETTING, AND PARTICIPANTS

A randomised (1:1), double-blind, placebo-controlled trial was conducted at 126 centres in 17 countries (October 2018-January 2020). Patients had mCRPC and no prior systemic mCRPC treatment.

INTERVENTION

Olaparib (300 mg bid) or placebo with abiraterone (1000 mg od) plus prednisone/prednisolone (5 mg bid).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The data cut-off date was July 30, 2021. Safety was assessed by AE reporting (Common Terminology Criteria for Adverse Events v4.03) and analysed descriptively.

RESULTS AND LIMITATIONS

The most common AEs (all grades) for olaparib plus abiraterone versus placebo plus abiraterone were anaemia (46.0% vs 16.4%), nausea (28.1% vs 12.6%), and fatigue (27.9% vs 18.9%). Grade ≥3 anaemia occurred in 15.1% versus 3.3% of patients in the olaparib plus abiraterone versus placebo plus abiraterone arm. The incidences of the most common AEs for olaparib plus abiraterone peaked early, within 2 mo, and were managed typically by dose modifications or standard medical practice. Overall, 13.8% versus 7.8% of patients discontinued treatment with olaparib plus abiraterone versus placebo plus abiraterone because of an AE; 3.8% versus 0.8% of patients discontinued because of anaemia. More venous thromboembolism events were observed in the olaparib plus abiraterone arm (any grade, 7.3%; grade ≥3, 6.8%) than in the placebo plus abiraterone arm (any grade, 3.3%; grade ≥3, 2.0%), most commonly pulmonary embolism (6.5% vs 1.8% for olaparib plus abiraterone vs placebo plus abiraterone).

CONCLUSIONS

Olaparib plus abiraterone has a manageable and predictable safety profile.

PATIENT SUMMARY

The PROpel trial showed that in patients who had not received any previous treatment for metastatic castration-resistant prostate cancer, olaparib combined with abiraterone was more effective in delaying progression of the disease than abiraterone alone. Most side effects caused by combining olaparib with abiraterone could be managed with supportive care methods, by pausing olaparib administration for a short period of time and/or by reducing the dose of olaparib.

Repeat Next-Generation Sequencing Testing on Progression in Men With Metastatic Prostate Cancer Can Identify New Actionable Alterations

PURPOSE

There are limited data available on the real-world patterns of molecular testing in men with advanced prostate cancer. We thus sought to evaluate next-generation sequencing (NGS) testing in the United States, focused on single versus serial NGS testing, the different disease states of testing (hormone-sensitive v castration-resistant, metastatic vs nonmetastatic), tissue versus plasma circulating tumor DNA (ctDNA) assays, and how often actionable data were found on each NGS test.

METHODS

The Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort clinical-genomic database was used for this retrospective analysis, including 1,597 patients across 15 institutions. Actionable NGS data were defined as including somatic alterations in homologous recombination repair genes, mismatch repair deficiency, microsatellite instability (MSI-high), or a high tumor mutational burden ≥10 mut/MB.

RESULTS

Serial NGS testing (two or more NGS tests with specimens collected more than 60 days apart) was performed in 9% (n = 144) of patients with a median of 182 days in between test results. For the second NGS test and beyond, 82.1% (225 of 274) of tests were from ctDNA assays and 76.1% (217 of 285) were collected in the metastatic castration-resistant setting. New actionable data were found on 11.1% (16 of 144) of second NGS tests, with 3.5% (5 of 144) of tests detecting a new BRCA2 alteration or MSI-high. A targeted therapy (poly (ADP-ribose) polymerase inhibitor or immunotherapy) was given after an actionable result on the second NGS test in 31.3% (5 of 16) of patients.

CONCLUSION

Repeat somatic NGS testing in men with prostate cancer is infrequently performed in practice and can identify new actionable alterations not present with initial testing, suggesting the utility of repeat molecular profiling with tissue or blood of men with metastatic castration-resistant prostate cancer to guide therapy choices.

Olaparib Combined with Abiraterone versus Olaparib Monotherapy for Patients with Metastatic Castration-resistant Prostate Cancer Progressing after Abiraterone and Harboring DNA Damage Repair Deficiency: A Multicenter Real-world Study

BACKGROUND AND OBJECTIVE

Olaparib + abiraterone has a combined antitumor effect in metastatic castration-resistant prostate cancer (mCRPC), but the efficacy of this combination in patients with DNA damage repair (DDR)-deficient mCRPC progressing after abiraterone is unknown. Our aim was to compare the efficacy of olaparib + abiraterone versus olaparib monotherapy for patients with DDR-deficient mCRPC progressing after abiraterone.

METHODS

The study included 86 consecutive patients with DDR-deficient mCRPC progressing after abiraterone: 34 received olaparib + abiraterone, and 52 received olaparib monotherapy. DDR-deficient status was defined as the presence of a DDR gene with a pathogenic or likely pathogenic variant (DDR-PV), or with a variant of unknown significance (DDR-VUS). We assessed progression-free survival (PFS) and overall survival (OS) using the Kaplan-Meier method. Potential factors influencing PFS and OS were compared between the treatment arms using Cox proportional-hazards models. The prostate-specific antigen (PSA) response, the treatment effect across subgroups, and adverse events (AEs) were also evaluated.

KEY FINDINGS AND LIMITATIONS

Median follow-up was 9 mo. In the overall cohort, median PFS and OS were significantly longer in the combination arm than in the monotherapy arm (PFS: 6.0 vs 3.0 mo; hazard ratio [HR] 0.41, 95% confidence interval [CI] 0.25-0.67; p < 0.01; OS: 25.0 vs 12.0 mo; HR 0.30, 95% CI 0.14-0.67; p < 0.01). PSA responses were significantly higher following combination therapy versus monotherapy. Combination therapy had significantly better efficacy in the DDR-PV and DDR-VUS subgroups, and was an independent predictor of better PFS and OS. AE rates were acceptable. The retrospective nature, small sample size, and short follow-up are limitations.

CONCLUSIONS

Olaparib + abiraterone resulted in better PFS and OS than olaparib alone for patients with DDR-deficient mCRPC progressing after abiraterone. These results need to be confirmed by a large-scale prospective randomized controlled trial.

PATIENT SUMMARY

Our study shows that the drug combination of olaparib plus abiraterone improved survival over abiraterone alone for patients who have mutations in genes affecting DNA repair and metastatic prostate cancer resistant to hormone therapy. The results provide evidence of a synergistic effect of the two drugs in these patients.

Inherited Mutations in DNA Damage Repair Genes in Italian Men with Metastatic Prostate Cancer: Results from the Meet-URO 10 Study

Background

The prevalence of pathogenic germline mutations in DNA damage repair (gDDR) genes in the Italian population is unknown.

Objective

In this prospective multicenter cohort study, we evaluated the prevalence of gDDR alterations in the Italian population affected by metastatic prostate cancer (mPCa) and analyzed the impact on response to therapy, survival, and time to castration resistance.

Design setting and participants

In an observational prospective trial, 300 consecutive Italian mPCa patients, enrolled in the Meet-Uro-10 trial from three academic Italian centers, were recruited between 2017 and 2019 and were screened for gDDR mutations in 107 genes.

Outcome measurements and statistical analysis

The primary endpoint was to assess the prevalence of gDDR mutations in the Italian population of patients with mPCa. The secondary endpoints included the association of gDDR subgroups with metastatic onset, Gleason score, and time to castration resistance.

Results and limitations

We identified 297 valuable patients. Forty-six patients had a pathogenic/likely pathogenic variant (15.5%, 95% confidence interval: 11.4-19.6): the more frequent was gBRCA2 found in nine cases (3%), followed by gATM in five cases (1.7%). In patients without mutations, longer median overall survival was observed with the sequence docetaxel-androgen receptor signaling inhibitor (ARSI) than with the sequence ARSI-docetaxel (87.9 vs 42 mo, p = 0.0001). In a univariate analysis, the median time to castration resistance in gDDR mutated patients was 19.8 mo, versus 23.7 mo in no mutated patients (p = 0.024). There were no associations of gDDR subgroups with metastatic onset and Gleason score ≥8. In our cohort, variants of unknown significance in gDDR genes were found in 80 patients and might have a prognostic relevance.

Conclusions

The study reported the prevalence of gDDR in the Italian population. The presence of gBRCA2 mutations correlates with a shorter time to the onset of castration resistance disease.

Patient summary

The prevalence of gBRCA2 in the Italian population is 3%, which is similar to that in the Spanish population, identifying similarities between people of the Western Mediterranean area.

TARGET: A Randomized, Noninferiority Trial of a Pretest, Patient-Driven Genetic Education Webtool Versus Genetic Counseling for Prostate Cancer Germline Testing

PURPOSE

Germline genetic testing (GT) is important for prostate cancer (PCA) management, clinical trial eligibility, and hereditary cancer risk. However, GT is underutilized and there is a shortage of genetic counselors. To address these gaps, a patient-driven, pretest genetic education webtool was designed and studied compared with traditional genetic counseling (GC) to inform strategies for expanding access to genetic services.

METHODS

Technology-enhanced acceleration of germline evaluation for therapy (TARGET) was a multicenter, noninferiority, randomized trial (ClinicalTrials.gov identifier: NCT04447703) comparing a nine-module patient-driven genetic education webtool versus pretest GC. Participants completed surveys measuring decisional conflict, satisfaction, and attitudes toward GT at baseline, after pretest education/counseling, and after GT result disclosure. The primary end point was noninferiority in reducing decisional conflict between webtool and GC using the validated Decisional Conflict Scale. Mixed-effects regression modeling was used to compare decisional conflict between groups. Participants opting for GT received a 51-gene panel, with results delivered to participants and their providers.

RESULTS

The analytic data set includes primary outcome data from 315 participants (GC [n = 162] and webtool [n = 153]). Mean difference in decisional conflict score changes between groups was -0.04 (one-sided 95% CI, -∞ to 2.54; P = .01), suggesting the patient-driven webtool was noninferior to GC. Overall, 145 (89.5%) GC and 120 (78.4%) in the webtool arm underwent GT, with pathogenic variants in 15.8% (8.7% in PCA genes). Satisfaction did not differ significantly between arms; knowledge of cancer genetics was higher but attitudes toward GT were less favorable in the webtool arm.

CONCLUSION

The results of the TARGET study support the use of patient-driven digital webtools for expanding access to pretest genetic education for PCA GT. Further studies to optimize patient experience and evaluate them in diverse patient populations are warranted.

Contemporary Systemic Therapy Intensification for Prostate Cancer: A Review for General Practitioners in Oncology

Prostate cancer accounts for a significant proportion of cancer diagnoses in Canadian men. Over the past decade, the therapeutic landscape for the management of metastatic prostate cancer has undergone rapid changes. Novel strategies use hormonal agents, chemotherapy, homologous recombination repair inhibitors, and radioligand therapy or combination strategies in addition to androgen deprivation therapy. In this review, we summarize the available data addressing key therapeutic areas along the disease continuum and focus on practical aspects for general practitioners in oncology managing patients with metastatic prostate cancer.

PROMISE Registry: A prostate cancer registry of outcomes and germline mutations for improved survival and treatment effectiveness

BACKGROUND

Recently approved treatments and updates to genetic testing recommendations for prostate cancer have created a need for correlated analyses of patient outcomes data via germline genetic mutation status. Genetic registries address these gaps by identifying candidates for recently approved targeted treatments, expanding clinical trial data examining specific gene mutations, and understanding effects of targeted treatments in the real-world setting.

METHODS

The PROMISE Registry is a 20-year (5-year recruitment, 15-year follow-up), US-wide, prospective genetic registry for prostate cancer patients. Five thousand patients will be screened through an online at-home germline testing to identify and enroll 500 patients with germline mutations, including: pathogenic or likely pathogenic variants and variants of uncertain significance in genes of interest. Patients will be followed for 15 years and clinical data with real time patient reported outcomes will be collected. Eligible patients will enter long-term follow-up (6-month PRO surveys and medical record retrieval). As a virtual study with patient self-enrollment, the PROMISE Registry may fill gaps in genetics services in underserved areas and for patients within sufficient insurance coverage.

RESULTS

The PROMISE Registry opened in May 2021. 2114 patients have enrolled to date across 48 US states and 23 recruiting sites. 202 patients have met criteria for long-term follow-up. PROMISE is on target with the study's goal of 5000 patients screened and 500 patients eligible for long-term follow-up by 2026.

CONCLUSIONS

The PROMISE Registry is a novel, prospective, germline registry that will collect long-term patient outcomes data to address current gaps in understanding resulting from recently FDA-approved treatments and updates to genetic testing recommendations for prostate cancer. Through inclusion of a broad nationwide sample, including underserved patients and those unaffiliated with major academic centers, the PROMISE Registry aims to provide access to germline genetic testing and to collect data to understand disease characteristics and treatment responses across the disease spectrum for prostate cancer with rare germline genetic variants.