Introduction
Prostate-specific membrane antigen (PSMA)—a transmembrane enzyme highly expressed on prostate adenocarcinoma cells—has become the defining molecular target of precision oncology in advanced prostate cancer. Over the past five years, PSMA-directed theranostics have evolved from compassionate-use programs into fully established, guideline-endorsed treatment modalities. The field now encompasses approved beta-emitting radioligand therapies (RLT), late-stage challenger agents with distinct isotope and scaffold designs, and an emerging generation of alpha-emitting conjugates aiming to overcome resistance and improve depth of response. This narrative review, current through July 2026, synthesizes pivotal clinical evidence, the competitive product pipeline, diagnostic workflow standards, and key outstanding questions for practicing oncologists, nuclear medicine physicians, urologists, and clinical researchers.
Approved Therapy: Lutetium-177 PSMA-617 (Pluvicto)
Lutetium-177 (¹⁷⁷Lu) vipivotide tetraxetan (Pluvicto; 177Lu-PSMA-617) remains the anchor approved product in this therapeutic class. Its foundational evidence derives from the pivotal phase 3 VISION trial, which randomized 831 patients with progressive PSMA-positive metastatic castration-resistant prostate cancer (mCRPC) following at least one androgen receptor pathway inhibitor (ARPI) and one to two taxane regimens to 177Lu-PSMA-617 plus protocol-permitted standard of care (SoC) versus SoC alone. The radioligand arm demonstrated a median radiographic progression-free survival (rPFS) of 8.7 months versus 3.4 months (hazard ratio [HR] 0.40; P<0.001) and a median overall survival (OS) of 15.3 months versus 11.3 months (HR 0.62; P<0.001). Objective response rate was 29.8% versus 1.7%. The European Medicines Agency (EMA) granted marketing authorization on 9 December 2022 13.
The post-chemotherapy safety profile is characterized by increased grade 3 or higher adverse events (52.7% versus 38.0% with SoC), driven primarily by hematologic toxicities including anemia (12.9%), thrombocytopenia (7.9%), and lymphopenia (7.8%). Common lower-grade effects include fatigue, xerostomia (dry mouth), nausea, and constipation. Importantly, patient-reported quality of life was not adversely affected in the VISION population 311.
Earlier-Line Expansion: PSMAfore and mHSPC
On 28 March 2025, the U.S. FDA expanded Pluvicto's indication to include taxane-naive mCRPC patients who had progressed on one ARPI and were deemed appropriate for chemotherapy delay, based on the PSMAfore trial (NCT04689828). This randomized, open-label phase 3 study (n=468) compared 177Lu-PSMA-617 (7.4 GBq every 6 weeks for 6 doses) to an ARPI switch (abiraterone or enzalutamide). The primary endpoint favored radioligand therapy: median rPFS 9.3 vs. 5.6 months(HR 0.41; P<0.0001). Quality-of-life analyses were supportive, with longer FACT-P (Functional Assessment of Cancer Therapy–Prostate) maintenance (7.5 vs. 4.3 months) and delayed pain worsening. Notably, grade ≥3 adverse events were numerically lower with Pluvicto (36%) than with ARPI switch (48%), and serious adverse events were 20% versus 32%. High crossover (60–84% of the ARPI arm) complicates OS interpretation; the unadjusted OS HR was not statistically significant, though crossover-adjusted exploratory analyses suggested a directional benefit 21324.
A phase 3 study (NCT04720157) is further expanding Pluvicto into metastatic hormone-sensitive prostate cancer (mHSPC), combining radioligand therapy with ARPI plus androgen deprivation therapy (ADT). An interim readout reported that the primary rPFS endpoint was met with a statistically significant and clinically meaningful benefit, and OS showed a positive trend; mature quantitative survival data were not available in the retrieved materials 13.
Competitive Landscape and Pipeline
Table 1. Approved and Late-Stage PSMA-Targeted Radiopharmaceutical Agents (as of July 2026)
| Agent | Isotope/Emitter | Mechanism/Scaffold | Developer(s) | Geography | Stage | Key Indication | Differentiating Feature |
|---|---|---|---|---|---|---|---|
| ¹⁷⁷Lu vipivotide tetraxetan (Pluvicto) | Lu-177 (β⁻) | Small-molecule PSMA ligand | Novartis | USA (Approved), EU (Approved), China (Phase III) | Approved / Phase III | Post-ARPI/post-taxane mCRPC; pre-taxane mCRPC (FDA 2025) | Only approved PSMA RLT; most extensive efficacy/safety dataset 1212 |
| ¹⁷⁷Lu-PNT2002 | Lu-177 (β⁻) | Small-molecule PSMA ligand (PSMA-I&T) | Lantheus / POINT Biopharma (Eli Lilly) | USA | Phase III / NDA Filed | Post-ARPI, taxane-naive mCRPC | SPLASH trial data; every-8-week dosing schedule; NDA filed 14 |
| TLX591-Tx (Rosopatamab tetraxetan; ATL-101) | Lu-177 (β⁻) | Monoclonal antibody radio-ADC (anti-PSMA) | Telix Pharmaceuticals | USA (IND discussion), Global (Phase III expanding) | Phase III (ProstACT Global) | Post-ARPI mCRPC | First antibody-based PSMA rADC; prolonged tumor retention; combination tolerability data 1512 |
| FPI-2265 (²²⁵Ac-PSMA-I&T) | Ac-225 (α) | Small-molecule PSMA ligand | Fusion Pharmaceuticals | USA | Phase II (AlphaBreak) | Prior Lu-177 PSMA–treated mCRPC | Alpha emitter for Lu-177–refractory disease; primary completion Dec 2026 16 |
| ²²⁵Ac-PSMA (compassionate use / retrospective) | Ac-225 (α) | Small-molecule PSMA ligand | Multiple centers | Australia, India, Germany, South Africa | Real-world evidence | Heavily pretreated mCRPC | WARMTH Act cohort; median OS 15.5 months; substantial xerostomia burden 17 |
| BAY-3546828 (²²⁵Ac-Pelgifatamab) | Ac-225 (α) | Small-molecule radiopharmaceutical | Lantheus / Bayer | USA | Phase I | mCRPC | Next-generation alpha emitter 12 |
| BAY-2315497 | Th-227 (α) | Antibody-targeted thorium conjugate | Bayer / Lantheus | USA | Phase I | mCRPC | Thorium-227 alpha strategy; antibody-based 12 |
| JH-02 | Lu-177 | Small molecule / theranostic | Bivision Biomedical (China) | China | Phase II | Prostate cancer | Theranostic asset; imaging-therapy ambiguity 12 |
| XTR-010 | Lu-177 (alias) | Small molecule | Beijing Sinotau | China | Phase II | Prostate cancer | China-specific pipeline entrant 12 |
Pivotal Clinical Evidence Summary
Table 2. Key Efficacy and Safety Results from Pivotal PSMA RLT Trials
| Trial | Agent | Setting | N (Randomized) | Comparator | Median rPFS (Experimental vs. Control) | Median OS (Experimental vs. Control) | PSA50 Response | Grade ≥3 AEs |
|---|---|---|---|---|---|---|---|---|
| VISION | ¹⁷⁷Lu-PSMA-617 | Post-ARPI/post-taxane mCRPC | 831 | SoC alone | 8.7 vs. 3.4 mo (HR 0.40; P<0.001) | 15.3 vs. 11.3 mo (HR 0.62; P<0.001) | ~46% | 52.7% vs. 38.0% 13 |
| PSMAfore | ¹⁷⁷Lu-PSMA-617 | Taxane-naive mCRPC, post-ARPI | 468 | ARPI switch | 9.3 vs. 5.6 mo (HR 0.41; P<0.0001) | OS HR <1.0 (not mature) | — | 36% vs. 48% 213 |
| SPLASH | ¹⁷⁷Lu-PNT2002 | Post-ARPI, taxane-naive mCRPC | 412 | ARPI switch | 9.5 vs. 6.0 mo (HR 0.71; P=0.0088) | Unadjusted HR 1.11 (84.6% crossover) | 35.7% vs. 14.6% | Grade ≥3: 9.7% vs. 11.5% 14 |
| TheraP | ¹⁷⁷Lu-PSMA-617 | Docetaxel-pretreated mCRPC | Randomized Ph II | Cabazitaxel | PSA-PFS HR 0.63 (P=0.007) | — | 66% vs. 37% (P<0.001) | 32% vs. 49% 13 |
| ENZA-p | ¹⁷⁷Lu-PSMA-617 + enzalutamide | Earlier mCRPC | Randomized Ph II | Enzalutamide alone | PSA-PFS 13.0 vs. 7.8 mo (HR 0.43) | — | Improved PSA50 and PSA90 | SAEs: 33% vs. 35% 13 |
Note: Cross-trial comparisons are not appropriate due to differences in patient populations, eligibility criteria, control arms, and crossover rates.
Mechanistic Differentiation: Beta vs. Alpha Emitters
The field is bifurcating along isotope strategy. Beta emitters (¹⁷⁷Lu), with a tissue penetration range of several millimeters and manageable hematologic toxicity, dominate the approved and late-stage pipeline. Alpha emitters—principally actinium-225 (²²⁵Ac) and thorium-227 (²²⁷Th)—deliver higher linear energy transfer (LET) radiation over shorter distances, theoretically more lethal to individual tumor cells and less dependent on bystander effect 910.
The largest real-world evidence dataset for alpha PSMA therapy is the WARMTH Act retrospective cohort (n=448 patients, seven international centers), which reported a median OS of 15.5 months and median PFS of 7.9 months with ²²⁵Ac-PSMA (8 MBq; median 2 cycles) in heavily pretreated patients 17. Prior treatments included docetaxel (66%), abiraterone or enzalutamide (39% each), and prior Lu-177 PSMA RLT (32%). Xerostomia (any grade) occurred in 68% of patients, and grade ≥3 hematologic events included anemia (13%), thrombocytopenia (7%), and leukopenia (4%). A compassionate-use study of ²²⁵Ac-PSMA-617 specifically in 26 patients who had progressed after ¹⁷⁷Lu-PSMA therapy showed a PSA50 response rate of 65%, median OS of 7.7 months, with grade 3/4 anemia in 35% and universally experienced xerostomia 4.
TLX591-Tx (rosopatamab tetraxetan), an antibody-based ¹⁷⁷Lu radio-antibody-drug conjugate, represents a mechanistically distinct approach. Part 1 of the global ProstACT Global phase 3 trial (n=36 patients across three cohorts combining TLX591-Tx with abiraterone, enzalutamide, or docetaxel) demonstrated that all patients completed both planned doses, with no unexpected safety signals. Grade 3/4 hematologic events included thrombocytopenia (31%) and neutropenia (25%), consistent with class effect. Favorable organ dosimetry—with liver receiving the highest absorbed dose (1.62–5.08 mGy/MBq) and minimal salivary gland exposure—and prolonged tumor retention were reported. Part 2 randomized expansion is actively recruiting globally, with FDA engagement underway for U.S. inclusion 15.
Next-Generation Approaches and Pipeline
Table 3. Next-Generation and Investigational PSMA-Targeted Strategies
| Strategy | Example Agents/Trials | Rationale | Current Limitation |
|---|---|---|---|
| Alpha emitters (²²⁵Ac) | FPI-2265 (AlphaBreak); ²²⁵Ac-FL-020; BAY-3546828 | Higher LET for deeper cytotoxicity; potential in Lu-177–refractory disease | Higher xerostomia and hematologic toxicity; supply constraints 1216 |
| Thorium-227 antibody conjugates | BAY-2315497 | Alpha emission with antibody-mediated tumor selectivity | Phase I; limited clinical data 12 |
| Combination with checkpoint inhibition | ¹⁷⁷Lu-PSMA-617 + pembrolizumab (LuPIN/phase 1) | Immunogenic cell death from radiation may potentiate anti-PD-1 response | Small phase 1; 56% ORR in part B; requires randomized confirmation 6 |
| Combination with ARPI | ENZA-p (enzalutamide + LuPSMA) | Synergistic PSA response; PSA-PFS 13.0 vs. 7.8 months | Phase II; no mature OS data 13 |
| Earlier-line use (mHSPC) | NCT04720157 (Pluvicto + ARPI + ADT) | Disease biology more PSMA-avid; patients more fit | OS maturity pending 13 |
| Biomarker-guided selection | ctDNA (TheraP), PSMA total tumor volume (ENZA-p) | Better prediction of benefit vs. resistance | Exploratory; not validated for routine use 13 |
| Dosimetry-guided personalization | VISION SPECT/CT substudy | Individualize administered activity to optimize tumor dose and spare organs | No outcome-linked dosing algorithm yet established 13 |
| Next-generation PSMA ligands | ¹⁷⁷Lu-rhPSMA-10.1; ludotadipep; LNC-1003 | Improved pharmacokinetics, tumor uptake, or theranostic flexibility | Phase I/II stage 12 |
Diagnostic and Theranostic Workflow
Central to the safe and effective use of all PSMA-targeted RLT is a rigorous theranostic workflow, as formalized by EANM/SNMMI procedure guidelines (2023, current through 2026) and ESMO 2026 clinical practice guidelines. PSMA PET/CT is mandatory for patient selection: ¹⁷⁷Lu-PSMA-617 is recommended for patients with one or more PSMA-positive lesions and no PSMA-negative metastases on baseline imaging—a criterion directly predicting therapeutic response 181920. Approved PSMA-directed PET radiotracers include ⁶⁸Ga-PSMA-11, ¹⁸F-DCFPyL, ¹⁸F-PSMA-1007, and ¹⁸F-rhPSMA-7.3, with no current evidence of superior diagnostic accuracy among them 18.
Eligibility for RLT further requires adequate renal function (typically eGFR ≥45 mL/min/1.73m²), acceptable bone marrow reserve (hemoglobin, platelet, and white cell thresholds), a life expectancy of at least 3–6 months, and absence of significant salivary gland uptake predicting xerostomia risk 20. Post-treatment SPECT/CT confirms biodistribution; PSA monitoring tracks biochemical response. The EANM/SNMMI/IAEA enabling guide on theranostics center establishment highlights the multidisciplinary infrastructure—including nuclear medicine, radiation oncology, medical oncology, and urology—required for safe program operation 23. The TheraP trial correlative analyses raise an additional long-term safety consideration: the detection of clonal hematopoiesis—with enrichment of PPM1D, ATM, and CHEK2 mutations—after ¹⁷⁷Lu-PSMA-617, underscoring the importance of sustained bone marrow surveillance, particularly as RLT moves to earlier disease stages 13.
Sequencing, Unresolved Questions, and Future Directions
Despite the remarkable maturation of this field, several critical clinical questions remain unanswered in the retrieved evidence base:
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Optimal sequencing: No direct comparative evidence establishes the ideal position of PSMA RLT relative to taxane chemotherapy, PARP inhibitors (for homologous recombination repair–deficient disease), or immunotherapy. Most current cases lack head-to-head comparative studies across agents, leaving therapeutic sequence largely consensus-driven 78.
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Earlier-line integration: PSMAfore and NCT04720157 support movement into pre-taxane mCRPC and mHSPC respectively, but mature OS data are needed to confirm long-term survival impact and to resolve sequencing concerns regarding subsequent therapy options 213.
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Resistance mechanisms and management: A major clinical challenge is resistance to PSMA RLT, including PSMA expression loss (identifiable as PSMA-negative FDG-avid disease on dual-tracer imaging), genomic heterogeneity, and ctDNA burden. Alpha emitters may partly address resistance, but this remains investigational 913.
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Dosimetry-guided individualization: Whether routine dosimetry can personalize administered activity to improve the therapeutic index is under investigation but not yet clinical practice 1325.
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Combination strategies: Preliminary phase 1 data for PSMA RLT plus pembrolizumab (56% ORR with a single priming dose followed by maintenance) and phase 2 ENZA-p data (combination with enzalutamide improving PSA-PFS) are encouraging but require phase 3 confirmation 613.
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China-specific pipeline: The China landscape features Pluvicto in phase III registration, and mid-stage domestic programs (JH-02, XTR-010), but mature clinical outcome data in retrieved materials were limited 12.
In summary, ¹⁷⁷Lu-PSMA-617 (Pluvicto) is the established clinical standard, with robust survival benefit in post-ARPI/post-taxane mCRPC and expanding regulatory approvals into earlier disease settings. The competitive field is rapidly diversifying—through alternative small-molecule beta-emitter ligands (¹⁷⁷Lu-PNT2002), first-in-class antibody radio-conjugates (TLX591-Tx), and a wave of alpha-emitter programs (FPI-2265, BAY-3546828, BAY-2315497) targeting Lu-177–refractory and heavily pretreated populations. Hematologic toxicity monitoring, PSMA PET–based patient selection, multidisciplinary theranostics infrastructure, and systematic long-term follow-up for marrow effects are the practical cornerstones of safe implementation. As earlier-line randomized evidence matures and combination strategies are validated, PSMA-targeted radiopharmaceuticals are poised to further redefine the precision medicine landscape across the full spectrum of advanced prostate cancer management 5810.