2024–2025 Clinical & Translational Update — PARP Inhibitors, PSMA Radioligand Therapy, Next-Generation ARPIs, Bispecific Antibodies, HRR Biomarkers & ctDNA-Guided Strategies
Prostate cancer remains the most commonly diagnosed non-skin cancer in men and the second leading cause of cancer death in the United States. The treatment landscape has undergone profound transformation — from androgen deprivation monotherapy to novel androgen receptor pathway inhibitors (ARPIs), PARP inhibitors, and PSMA-targeted radioligand therapy — with biomarker-driven precision strategies now redefining sequencing decisions. The defining challenge in 2025 is the heterogeneous management of metastatic castration-resistant prostate cancer (mCRPC), particularly in patients with DNA repair alterations, and the sequencing of increasingly active agents after prior ARPI exposure.
Enzalutamide · Abiraterone · Darolutamide · Apalutamide
Olaparib · Rucaparib · Niraparib · Talazoparib
Lutetium-177 PSMA-617 (Pluvicto) · Actinium-225 PSMA
Acasunlimab (AMG 160) · Tarlatamab · Pembrolizumab
ARV-110 (bavdegalutamide) · ODM-208 · EPI-7386
AR-V7 · HRR cfDNA · PSMA PET-guided selection
Landmark trial expanding Lu-177 PSMA-617 indication to taxane-naïve mCRPC patients progressing on prior ARPI. 59% reduction in risk of radiographic progression or death vs ARPI switch. Updated OS data presented at ASCO 2024 confirms durable benefit and supports earlier use of radioligand therapy in the treatment sequence.
Updated OS data at ASCO 2024: niraparib + abiraterone/prednisone demonstrated significant OS benefit in BRCA1/2-mutant mCRPC (HR 0.54; median OS 19.5 vs 14.1 months). No OS benefit in non-BRCA HRR-mutant or HRR-non-mutant populations — reinforcing the critical importance of BRCA biomarker selection for PARPi + ARPI combinations.
Talazoparib + enzalutamide demonstrated rPFS benefit across unselected mCRPC (HR 0.63) with greatest benefit in HRR-mutant patients. FDA approved June 2023. Updated 2024 data confirm sustained rPFS benefit and PSA50 response enrichment in BRCA1/2 and CDK12-mutant subgroups. Anemia (46%) is the most frequent Grade ≥3 AE due to talazoparib's potent PARP trapping.
Five-year follow-up confirms sustained OS benefit of the darolutamide triplet in metastatic castration-sensitive prostate cancer (mCSPC). 32.5% reduction in risk of death (HR 0.68) maintained at longer follow-up. Darolutamide's favorable CNS penetration profile and minimal drug interactions distinguish it from enzalutamide and apalutamide — particularly relevant in patients on antiepileptics or anticoagulants.
In patients with high-risk biochemical recurrence (BCR) following radical prostatectomy or radiotherapy, enzalutamide + leuprolide significantly improved MFS (HR 0.42) and enzalutamide monotherapy showed MFS benefit vs placebo (HR 0.63). First Phase 3 trial to demonstrate MFS benefit in the BCR setting — FDA approved enzalutamide for this indication in 2024, expanding the ARPI landscape upstream of metastatic disease.
Half-life extended PSMA×CD3 bispecific T-cell engager with promising activity in heavily pretreated mCRPC. ORR ~53% (PSA50) in post-ARPI, post-taxane patients. CRS manageable with step-up dosing; no on-target off-tumor salivary toxicity observed at therapeutic doses. Phase 2 expansion ongoing; combination with checkpoint inhibitors under evaluation as of 2025.
Significant cross-resistance exists between enzalutamide and abiraterone — sequential ARPI use is frequently ineffective. The optimal post-ARPI strategy — docetaxel, cabazitaxel, Lu-177 PSMA, or PARPi — depends critically on HRR mutation status and PSMA expression. Rational biomarker-driven sequencing is now essential.
PARPi + ARPI combinations (PROpel, MAGNITUDE, TALAPRO-2) improve outcomes but increase hematological toxicity — particularly anemia and thrombocytopenia with talazoparib. Restricting combinations to biomarker-selected (BRCA1/2) populations maximizes benefit:risk ratio and avoids overtreatment in unselected patients.
15–20% of mCRPC patients have PSMA-low or PSMA-negative disease on PET imaging — excluding them from radioligand therapy. FDG-avid / PSMA-negative tumors (discordant pattern) carry the poorest prognosis. PSMA expression is lost in NEPC lineage-switched tumors — an emerging therapeutic gap.
Treatment-induced NEPC (t-NEPC) occurs in ~15–20% of mCRPC after prolonged ARPI exposure. Driven by TP53 + RB1 co-loss, it is AR-null, PSMA-low, and refractory to most standard therapies. Platinum-etoposide, alisertib, and tarlatamab (DLL3 bispecific) represent active investigational strategies.
NCCN and EAU guidelines now recommend germline HRR testing for all metastatic prostate cancer patients — and somatic tumor testing for mCRPC. Real-world implementation remains variable. BRCA2 germline carriers have a 5-8x increased prostate cancer risk — cascade family testing is underutilized.
Post-Lu-177 PSMA therapy sequencing is incompletely defined. Bone marrow reserve limitations after radioligand therapy may restrict subsequent taxane chemotherapy or PARPi use. Optimal sequencing of Lu-177 relative to docetaxel, cabazitaxel, and PARPi in the mCRPC treatment continuum remains an active research priority.
Localized / biochemical recurrence: Active surveillance (low-risk); radical prostatectomy or radiotherapy ± ADT for intermediate/high-risk. High-risk BCR post-definitive therapy: Enzalutamide ± leuprolide (EMBARK data, FDA approved 2024) — first demonstrated MFS benefit in this setting.
Metastatic castration-sensitive: ADT + ARPI (enzalutamide, apalutamide, darolutamide) ± docetaxel. High-volume/high-risk disease: darolutamide + docetaxel + ADT triplet (ARASENS) or enzalutamide + ADT (ARCHES). Obtain germline HRR testing at this stage. PSMA PET staging now standard of care.
Post-ADT, ARPI-naïve: ARPI (enzalutamide or abiraterone) ± PARPi if HRR mutant (olaparib + abiraterone, niraparib + abiraterone, talazoparib + enzalutamide). Perform somatic HRR/tumor testing and PSMA PET to guide sequencing. Docetaxel preferred in ARPI-pretreated or high-volume symptomatic disease.
BRCA1/2-mutant mCRPC post-ARPI: PARP inhibitor monotherapy (olaparib or rucaparib) — highest single-agent activity. PSMA+ disease post-ARPI + taxane: Lu-177 PSMA-617 (VISION criteria) or PSMAfore protocol (pre-taxane). MSI-H: pembrolizumab. AR LBD mutation: ARV-110 (bavdegalutamide — investigational).
Post-ARPI + post-taxane + post-PARPi or post-RLT: Cabazitaxel if taxane-naïve; clinical trial enrollment is the priority. Investigational options: PSMA×CD3 bispecific (AMG 160/acasunlimab), actinium-225 PSMA (alpha-emitter), novel AR degraders (ARV-110), CDK4/6 inhibitors in RB1-loss, LSD1 inhibitors or alisertib in t-NEPC.
Prostate cancer treatment has entered a biomarker-stratified era. HRR mutation testing — particularly BRCA1/2 — is no longer optional: it directly determines PARPi eligibility and has now demonstrated an OS benefit in the mCRPC setting (MAGNITUDE). Simultaneously, PSMA-targeted radioligand therapy has rapidly expanded its footprint with PSMAfore demonstrating compelling rPFS benefit even before chemotherapy exposure, challenging traditional treatment sequencing assumptions.
The emergence of treatment-induced neuroendocrine prostate cancer (t-NEPC) represents the most urgent unmet need — an AR-null, PSMA-low phenotype refractory to virtually all standard modalities. Early detection through liquid biopsy (TP53/RB1 cfDNA) and novel targets (DLL3, AURKA) offer the first rational therapeutic footholds in this aggressive variant.
The next paradigm shift is the integration of ctDNA-guided therapy switching, real-time resistance monitoring, and rational combination sequencing — moving away from empirical progression-based switching toward molecularly driven, adaptive treatment architectures.
Key trials to watch: AMPLITUDE (olaparib + abiraterone OS update), PSMAfore OS data, AMG 160 Phase 2 expansion, TALAPRO-3 (talazoparib + enzalutamide in mCSPC), alisertib NEPC trials, and Lu-177 PSMA combination data at ASCO 2025 and ESMO 2025.