Prostate cancer has seen two transformative advances in the past five years: PSMA-targeted radioligand therapy that delivers targeted radiation directly to tumor cells expressing a prostate-specific membrane antigen, and PARP inhibitors that exploit DNA repair deficiencies in patients with BRCA1/2 and other homologous recombination mutations. Neither approach was in routine clinical use a decade ago. In 2026, the question has moved beyond "do these work?" to "where should they go in the treatment sequence?" — trials are now testing whether earlier use improves outcomes and whether combinations can delay or overcome resistance. For patients, the molecular complexity of this trial landscape is considerable, but the payoff is a set of treatment options that is meaningfully better than what existed previously.
This article is for informational purposes only and does not constitute medical advice. Clinical trial eligibility and availability vary. Always consult a qualified healthcare professional before making any medical decisions or considering participation in a clinical trial.
Summary
Prostate cancer is now a biomarker-stratified disease — treatment decisions in metastatic castration-resistant prostate cancer (mCRPC) depend on PSMA expression status, BRCA1/2 and HRR mutation status, AR splice variant 7 (AR-V7) status, and prior treatment history. In 2026, over 500 prostate cancer trials are recruiting globally. The three most active areas are PSMA-targeted radioligand therapy (Pluvicto approved 2022, trials now testing earlier use), PARP inhibitors in BRCA-mutated mCRPC (olaparib, rucaparib, niraparib approved; combinations in trials), and AR pathway approaches targeting resistance mechanisms. Getting the molecular profiling done before evaluating trial eligibility is essential.
ClinicalMetric Analysis
- PSMA expression heterogeneity — some tumor cells express PSMA while others don't — means PSMA-RLT leaves PSMA-negative clones to progress, which likely explains why VISION trial responses were meaningful but not curative, and drives the combination strategy rationale. The VISION trial showed significant OS and PFS benefit, but 24% of patients were PSMA-negative by PSMA PET and were excluded entirely. Among PSMA-positive enrollees, responses were meaningful but most patients progressed — PSMA-negative clonal expansion under PSMA-targeting selective pressure is the hypothesized resistance mechanism. Combining PSMA-RLT with PARP inhibition (for the HRR-deficient subgroup whose DNA repair deficiency makes them doubly sensitive to radiation-mediated DNA damage) is the most mechanistically coherent combination approach currently in trials. The PSMAddition + olaparib combination trial design is testing this hypothesis directly.
- Germline BRCA2 testing is now standard-of-care in mCRPC — and the cascade testing implication for family members is clinically important and systematically under-discussed in oncology visits. A man with mCRPC and a germline BRCA2 mutation has first-degree female relatives (sisters, daughters) with substantially elevated breast and ovarian cancer risk — BRCA2 confers approximately 45% lifetime breast cancer risk and 10–15% ovarian cancer risk. Current NCCN guidelines recommend referral to genetic counseling for all mCRPC patients who test positive for germline HRR mutations. The conversation about cascade testing for family members should happen at the oncology visit when germline results are disclosed, not be left to the patient to initiate independently. Genetic counselors at most comprehensive cancer centers will contact family members directly once the proband consents.
- AR splice variant 7 (AR-V7) status in circulating tumor cells predicts resistance to enzalutamide and abiraterone — and patients who are AR-V7 positive have very low response rates to ARPI cycling, making early switch to taxane chemotherapy or PSMA-RLT the evidence-supported alternative. AR-V7 is a constitutively active androgen receptor splice variant that lacks the ligand-binding domain targeted by enzalutamide and abiraterone — making it structurally insensitive to ARPI therapy regardless of dose. The PROPHECY trial demonstrated that AR-V7-positive patients have near-zero PSA response rates to enzalutamide or abiraterone switch. AR-V7 testing from ctCTC (circulating tumor cell) or ctDNA is available at several commercial labs (Epic Sciences, Genomic Health) and academic centers. For mCRPC patients who have rapidly progressed on one ARPI, AR-V7 testing before switching to the other ARPI class member is a practical precision oncology decision that avoids months of ineffective treatment.
PSMA-Targeted Radioligand Therapy: From Approval to Sequencing Questions
Lutetium-177 PSMA-617 (Pluvicto, Novartis) received FDA approval in March 2022 for PSMA-positive mCRPC following prior ARPI therapy and taxane-based chemotherapy. The VISION trial (NCT03511664) showed improved radiographic PFS (HR 0.40, p<0.001) and improved OS (HR 0.62, p<0.001) versus best supportive care in heavily pre-treated patients. The drug works by binding PSMA — a membrane protein highly expressed on prostate cancer cells — and delivering Lu-177, a beta-emitting radioisotope, directly to the tumor cell, sparing surrounding normal tissue.
What makes the 2026 trial landscape interesting is that the approval question has been answered. The current questions are about sequence and combination. Active trials include:
- Earlier use in hormone-sensitive disease: The PSMAfore trial (NCT04689828) tested Pluvicto vs. ARPI switch in ARPI-pretreated mCRPC, and data is maturing. The PSMAaddition trial is testing Pluvicto in metastatic hormone-sensitive prostate cancer — before castration resistance develops.
- Actinium-225 PSMA (alpha emitter): Ac-225 delivers alpha radiation, which has shorter range but higher local energy deposition than the beta emission of Lu-177. Phase 2 trials show response rates in the 70–80% range in patients who have already progressed on Lu-177 PSMA — the alpha emitter appears to work even after beta failure. Phase 3 trials are being designed.
- PSMA-directed CAR-T: Phase 1 trials at MSKCC and other centers are testing PSMA-targeted CAR-T cells in mCRPC. Very early, very small numbers, but represents the extension of the CAR-T approach to a solid tumor with a well-validated surface target.
- Combinations with PARP inhibitors: PSMA therapy causes DNA damage; PARP inhibitors block DNA repair. The combination is mechanistically rational for BRCA-mutated tumors. Phase 1/2 combination trials are running.
PSMA PET scan — using tracers such as 68Ga-PSMA-11 (Illuccix) or 18F-DCFPyL (Pylarify) — is required to confirm adequate PSMA expression before eligibility for most PSMA-targeted therapy trials. If you have metastatic prostate cancer and have not had a PSMA PET, this is a critical conversation to have with your oncologist before evaluating trial eligibility.
PARP Inhibitors: The Approved Options and What Comes Next
The rationale for PARP inhibitors in prostate cancer is synthetic lethality: cells with homologous recombination repair (HRR) deficiencies — caused by mutations in BRCA1, BRCA2, ATM, CDK12, CHEK2, and other HRR genes — depend on PARP for alternative DNA repair. Block PARP, and the cell cannot repair double-strand DNA breaks, leading to death. In normal cells with functional HRR, backup repair pathways compensate. The selectivity is elegant.
Olaparib (Lynparza) received FDA approval for BRCA1/2-mutated mCRPC based on the PROfound trial (NCT02987543), which showed a 34% ORR and median rPFS of 7.4 months vs. 3.6 months for ARPI switch. Niraparib plus abiraterone (Akeega) was approved in 2023 for BRCA1/2-mutated mCRPC after the MAGNITUDE trial. Approximately 25% of mCRPC patients have HRR gene mutations, making HRR testing the first actionable biomarker evaluation after the diagnosis of castration resistance.
- Broader HRR populations: PROfound showed benefit primarily in BRCA1/2; the data for ATM and CDK12 mutations was less clear. Multiple trials are evaluating PARP inhibitors specifically in non-BRCA HRR-mutated mCRPC to characterize which HRR alterations beyond BRCA predict response.
- Earlier disease stages: The PROpel trial evaluated olaparib + abiraterone vs. abiraterone alone in unselected first-line mCRPC regardless of HRR status — showing rPFS benefit in the ITT population. Post-hoc analyses showed the benefit was concentrated in BRCA-mutated patients. Trials are now designing for frontline BRCA-selected populations.
- Combinations with immunotherapy: CDK12-mutated tumors have high focal tandem duplications that generate neoantigens — making them potentially immunogenic. Phase 2 trials combining PARP inhibitors with PD-1 checkpoint blockade in CDK12-mutated mCRPC are ongoing, attempting to generate an immune response in a tumor type otherwise resistant to immunotherapy.
AR Pathway Resistance and What Comes After ARPIs
Enzalutamide (Xtandi) and abiraterone (Zytiga/Yonsa) are first-generation ARPIs that transformed mCRPC treatment a decade ago. Enzalutamide in the PREVAIL trial reduced risk of death by 29% vs. placebo; abiraterone in COU-AA-301 extended OS by a median of 4.6 months in post-docetaxel patients. These drugs remain foundational. But resistance inevitably develops, and the mechanisms of resistance — principally AR splice variant 7 (AR-V7), AR gene amplification, and ARPI-cross resistant point mutations — are now reasonably well characterized and targetable.
- AR-V7 and resistance: AR-V7 is a constitutively active AR splice variant that lacks the ligand-binding domain — making it resistant to enzalutamide and abiraterone, which work by blocking ligand binding. AR-V7-positive patients rarely respond to ARPI switch. Testing for AR-V7 in circulating tumor cells (Oncotype DX AR-V7) or circulating tumor DNA is available clinically and guides decisions about switching to a different mechanism.
- PSMA × CD3 bispecific antibodies: T cell engaging bispecifics that bind PSMA on prostate cancer cells and CD3 on T cells simultaneously, redirecting cytotoxic T cells to kill tumor cells without prior sensitization. Tarlatamab for SCLC validated the bispecific T cell engager mechanism in solid tumors; PSMA-targeted bispecifics (xaluritamig, pasotuxizumab, AMG 160) are in Phase 1/2 for mCRPC with promising early response data.
- AKT inhibitors for PTEN-deleted mCRPC: PTEN deletion occurs in ~40% of mCRPC, activating the PI3K/AKT pathway. The IPATential150 trial showed capivasertib + abiraterone improved rPFS in PTEN-deleted patients (HR 0.56 vs. 0.92 in PTEN-normal patients). Further trials combining AKT inhibitors with ARPIs in PTEN-selected populations are active.
The Biomarker Workup Every mCRPC Patient Should Have Done
The practical problem in prostate cancer trial navigation in 2026 is that most trials require specific biomarker data that may not have been collected during standard oncology workup. Getting the right tests done before contacting trial sites avoids delays at pre-screening:
- Germline testing (blood): BRCA1, BRCA2, and full HRR panel. This is heritable testing — BRCA2 in particular has implications for family members. NCCN guidelines recommend germline testing for all metastatic prostate cancer patients.
- Somatic tumor profiling (tissue biopsy or liquid biopsy): HRR mutations, CDK12, MSI-H/dMMR, AR amplification/mutations. Somatic and germline BRCA mutations are different — a tumor can have somatic BRCA inactivation without germline carrier status, and both are actionable.
- PSMA PET: Required for PSMA-targeted therapy eligibility. Expression is scored on PSMA PET — high PSMA expression (score ≥2 on multiple lesions) is the typical threshold for trial eligibility.
- AR-V7 testing: From circulating tumor cells or ctDNA. Guides decisions about ARPI switch vs. non-AR mechanism trials in patients progressing on first-line ARPI.
- Prior treatment documentation: Most mCRPC trials require specific prior treatment sequences — ARPI-naive vs. ARPI-pretreated, taxane-pretreated vs. taxane-naive. Having a clear treatment timeline with dates and responses accelerates pre-screening substantially.
Key Takeaways
- Germline BRCA2 mutation is the most predictive single biomarker for mCRPC treatment decisions — olaparib and niraparib/abiraterone are FDA-approved for BRCA-mutated mCRPC. Get tested if you haven't, regardless of family history.
- PSMA PET imaging has transformed staging and therapeutic targeting. Lu-177 PSMA (Pluvicto) has Phase 3 OS data in mCRPC and is now FDA-approved — trials testing earlier use and Ac-225 alpha emitter approaches are active.
- AR-V7 positivity predicts resistance to enzalutamide and abiraterone. Patients with AR-V7 detected in circulating tumor cells should prioritize trials with non-AR mechanisms — PSMA therapy, PARP inhibitors, or bispecific antibodies.
- Comprehensive somatic tumor profiling and germline testing are complementary, not redundant — both should be completed before evaluating trial eligibility for mCRPC.
- GU oncology programs at NCI-designated Cancer Centers have the broadest prostate cancer trial portfolios. Coordinating biomarker workup before the consultation visit is the most efficient approach.
Finding Prostate Cancer Trials in 2026
Search ClinicalMetric for "prostate cancer" or "castration-resistant prostate cancer" filtered by Phase and Recruiting status. NCI-designated Cancer Centers with dedicated Genitourinary (GU) oncology programs have the broadest portfolio of prostate trials. PARP inhibitor trials require confirmed HRR mutation documentation — ensure germline and somatic profiling are completed before contacting trial sites to avoid delays in pre-screening. The ZERO Prostate Cancer patient advocacy organization maintains a trial navigation program and connects patients to GU oncology specialists.
Frequently Asked Questions
What prostate cancer treatments are in clinical trials in 2026?
Active 2026 trial areas: PARP inhibitors for HRR-mutant disease (olaparib, rucaparib combinations); lutetium-177 PSMA (Pluvicto) — now approved, trials testing earlier use; bispecific antibodies (PSMAxCD3); AR pathway novel agents; pembrolizumab combinations for MSI-H prostate cancer; and personalized cancer vaccines.
Should I get BRCA testing before joining a prostate cancer trial?
Yes. Germline and somatic testing for BRCA1/2 and other HRR genes is now standard. BRCA2-mutant metastatic prostate cancer qualifies for FDA-approved PARP inhibitors (olaparib, rucaparib, niraparib). Testing also identifies PALB2, ATM, CDK12 mutations that open additional trial eligibility. Ask for both germline (blood) and somatic (tumor) testing.
What is PSMA and how does it affect trial eligibility?
PSMA (prostate-specific membrane antigen) is overexpressed on prostate cancer cells — used as a diagnostic target (PSMA PET scan) and therapeutic target (lutetium-177 PSMA therapy). Most PSMA-targeted trials require a positive PSMA PET scan showing adequate target expression. PSMA PET is now widely available at major cancer centers.