Third-line Life-prolonging Drug Treatment in a Real-world Metastatic Castration-resistant Prostate Cancer Population: Results from the Dutch Castration-resistant Prostate Cancer Registry

Early Cost-Effectiveness Analysis of Using Whole-Genome Sequencing for Patients With Castration-Resistant Prostate Cancer

OBJECTIVES

This study aims to assess the potential cost-effectiveness of using whole-genome sequencing (WGS)-guided systemic therapy in metastatic castrate-resistant prostate cancer compared with the European Association of Urology guideline recommended diagnostics from a Dutch societal perspective.

METHODS

A decision analytic model combining a decision tree and partitioned survival models was developed to link diagnostic results with subsequent biomarker-guided treatments. Two diagnostic strategies, WGS and guideline-recommended practice-the genomic testing for breast cancer gene 1/2 (BRCA1/2) and deficient mismatch repair, were simulated to compare the health outcome and cost. Treatment effectiveness was estimated through survival analysis using published trial data. Sensitivity and scenario analyses were conducted to examine result robustness and to identify conditions under which WGS may be cost-effective.

RESULTS

WGS identified an additional 21% of patients eligible for personalized therapy (PD-1/PDL-1 inhibitors and olaparib), resulting in an incremental increase in cost (€14 260) and quality-adjusted life years (QALY = 0.05). These results yielded an incremental cost-effectiveness ratio of €289 625 per QALY gained. WGS would become cost-effective if the cost of biomarker-guided therapies decreases by 62% and when identifying a proportion of 23% more patients with actional targets.

CONCLUSIONS

Our findings suggest that future treatments with improved efficacy and reduced cost could potentially make the WGS strategy cost-effective. Its unaccounted potential value to identify prognostic biomarkers, diagnostic alternatives, and patient heterogeneity should be addressed in future research and considered for optimal implementation. New reimbursement options are needed considering the high prices of biomarker-guided therapies that drive the incremental cost-effectiveness ratio.

177Lu-PSMA Radioligand Therapy Is Favorable as Third-Line Treatment of Patients with Metastatic Castration-Resistant Prostate Cancer. A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

In this systematic review and network meta-analysis (NMA), we aimed to assess the benefits and harms of third-line (L3) treatments in randomized controlled trials (RCTs) of patients with metastatic castration-resistant prostate cancer (mCRPC). Two reviewers searched for publications from 1 January 2006 to 30 June 2021. The review analyzed seven RCTs that included 3958 patients and eight treatments. Treatment with prostate-specific membrane antigen (PSMA)-based radioligand therapy (PRLT) resulted in a 1.3-times-higher rate of median PSA decline ≥50% than treatment with abiraterone, enzalutamide, mitoxantrone, or cabazitaxel (p = 0.00001). The likelihood was 97.6% for PRLT to bring about the best PSA response, out of the examined treatments. PRLT resulted in a 1.1-times-higher six-month rate of median radiographic progression-free survival. Treatment with PRLT in the VISION trial resulted in 1.05-times-higher twelve-month median overall survival than L3 treatment with cabazitaxel in other RCTs. PRLT more often resulted in severe thrombocytopenia and less often in severe leukopenia than did cabazitaxel. In conclusion, for patients with mCRPC, L3 treatment with PRLT is highly effective and safe.

Clinical outcomes and molecular profiling of advanced metastatic castration-resistant prostate cancer patients treated with 225Ac-PSMA-617 targeted alpha-radiation therapy

INTRODUCTION

Targeted alpha-radiation therapy (TAT) with ²²⁵Ac-labeled prostate-specific membrane antigen (PSMA) ligands is a promising novel treatment option for metastatic castration-resistant prostate cancer (mCRPC) patients. However, limited data are available on efficacy, quality of life (QoL), and pretherapeutic biomarkers. The aim of this study was to evaluate the efficacy of ²²⁵Ac-PSMA TAT and impact on QoL in advanced mCRPC, and to explore predictive biomarkers on pretherapeutic metastatic tissue biopsies.

METHODS

Observational cohort study including consecutive patients treated with ²²⁵Ac-PSMA TAT between February 2016 and July 2018. Primary endpoint was overall survival (OS). Furthermore, prostate-specific antigen (PSA) changes, radiological response, safety, QoL, and xerostomia were evaluated. Biopsies were analyzed with immunohistochemistry and next-generation sequencing.

RESULTS

Thirteen patients were included. Median OS was 8.5 months for the total cohort and 12.6 months for PSMA radioligand therapy-naïve patients. PSA declines of ≥90% and ≥50% were observed in 46% and 69% of patients, respectively. Six patients were radiologically evaluable; 50% showed partial response. All patients showed >90% total tumor volume reduction on PET imaging. Patients experienced clinically relevant decrease of pain and QoL improvement in physical and role functioning domains. Xerostomia persisted during follow-up. Patients with high baseline immunohistochemical PSMA expression or DNA damage repair alterations tended to have longer OS.

CONCLUSIONS

TAT with ²²⁵Ac-PSMA resulted in remarkable survival and biochemical responses in advanced mCRPC patients. Patients experienced clinically relevant QoL improvement, although xerostomia was found to be nontransient. Baseline immunohistochemical PSMA expression and DNA damage repair status are potential predictive biomarkers of response to ²²⁵Ac-PSMA TAT.