Patients with metastatic castration-resistant prostate cancer (mCRPC) face poor prognoses due to tumor heterogeneity and drug resistance. Antibody-drug conjugates (ADCs) have been under development for over two decades for mCRPC treatment. Several clinical trials have demonstrated promising antitumor activity and acceptable safety profiles for ADCs in this setting. Among prostate-specific membrane antigen (PSMA)-targeted ADCs, ARX517 demonstrates superior safety and more significant prostate-specific antigen (PSA) reductions compared to earlier agents such as MLN2704, PSMA-ADC, and MEDI3726. ADCs targeting B7-H3, such as MGC018 and DB-1311, have also shown antitumor activity. ADCs targeting other antigens, including six-transmembrane epithelial antigen of the prostate (STEAP)1 (DSTP3086S), trophoblast cell surface antigen (TROP)2 (sacituzumab govitecan), and solute carrier (SLC) 44A4 (ASG-5ME), have shown preliminary antitumor activity in early trials but face challenges with insufficient efficacy or toxicity. Tisotumab vedotin (targeting tissue factor) has shown no significant therapeutic response in mCRPC. Meanwhile, disitamab vedotin (HER2-targeted), ABBV-969 and DXC008 (both dual PSMA/STEAP1-targeted) are currently under evaluation. Notably, an international multicenter phase Ⅲ clinical trial (NCT06925737) for mCRPC has been initiated in May 2025 for evaluating B7-H3-targeted ADC ifinatamab deruxtecan. This review summarizes recent advances in ADCs targeting key antigens in mCRPC (including PSMA, B7-H3, STEAP1, TROP2, SLC44A4, and others) and explores combination strategies, offering insights to inform the clinical management of mCRPC.
Humans ; Prostatic Neoplasms, Castration-Resistant/pathology* ; Male ; Immunoconjugates/therapeutic use* ; Glutamate Carboxypeptidase II/immunology* ; Antibodies, Monoclonal, Humanized/therapeutic use* ; B7 Antigens/immunology* ; Neoplasm Metastasis ; Prostate-Specific Antigen ; Antigens, Neoplasm/immunology* ; Antigens, Surface ; Camptothecin/analogs & derivatives* ; Oxidoreductases

OBJECTIVETo construct, express and purify human fusion proteins composed of a single-chain antibody fragment scFv that recognizes the prostate specific membrane antigen (PSMA) protein, Fdt, HA2 and tp, and to analyze the binding activity of the expressed fusion proteins.

METHODSThe fusion protein genes scFv, scFv-tp, and scFv-Fdt-HA2-tp were amplified by PCR, and the genes obtained were then cloned into the expression vector pET28 and expressed in E. coli BL21. The expressed products were identified by SDS-PAGE and Western blot and purified with Ni(2+)-NTA chelating agarose. The antigen-binding activity of the fusion proteins was determined by ELISA.

RESULTSThe human anti-PSMA fusion gene was successfully constructed and expressed in M15 as the inclusion body after induced with IPTG. All the target proteins expressed could bind the PSMA antigen.

CONCLUSIONFusion proteins can specifically bind the PSMA antigen. This finding contributes to the study of the targeted delivery of siRNA.

Antigens, Surface ; immunology ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; immunology ; Glutamate Carboxypeptidase II ; immunology ; Humans ; Male ; Polymerase Chain Reaction ; RNA, Small Interfering ; administration & dosage ; immunology ; Recombinant Fusion Proteins ; genetics ; immunology ; Single-Chain Antibodies ; genetics ; immunology

OBJECTIVETo investigate the clinical safety and effects of auto-dendritic cells pulsed with HLA-A201-binding peptides prostate-specific antigen (PSA) , prostate-specific membrane antigen (PSMA) and prostatic acid phosphatase (PAP) in the treatment of hormone-refractory metastatic prostate cancer (HRPC).

METHODSSixteen HRPC patients with positive HLA-A201 were enrolled and their monocytes isolated and induced into dendritic cells with the combination of rhGM-CSF and rhIL4. The patients were inoculated subcutaneously near the inguinal region with auto-DCs pulsed with peptides PSA (KLQCVDLHV) , PSMA (ALDVYNGL L) and PAP (LLHETDSAV) every 2 weeks for 4 times, and the immunological and clinical responses were examined within 1 -2 weeks after the final vaccination.

RESULTSVaccination of dendritic cells was well tolerated and no toxicity was observed. The cytokine levels in the serum such as IL-2, IL-12 and IFN-gamma were significantly increased after the vaccination (P < 0.01). The delayed type hyper- sensitivity (DTH) test was positive in 4 of the patients (4/11), the percentage of antigen-special IFN-gamma+ CD8+ T increased in 5 (5/11), the level of the tumor marker PSA decreased in 6 (6/16) , hydrops abdominis reduced in 1 (1/16), and the size of the cervical lymph node lessened in 1 (1/16). Three patients showed partial remission (PR), 7 stability of the disease (SD), and the other 6 progression of the disease (PD).

CONCLUSIONAuto-DC vaccines loaded with PSA, PSMA and PAP peptides, capable of eliciting specific immune responses in HRPC patients, is a safe and effective option for the treatment of advanced HRPC.

Acid Phosphatase ; Aged ; Antigens, Surface ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Cancer Vaccines ; immunology ; Cytokines ; blood ; Dendritic Cells ; immunology ; Glutamate Carboxypeptidase II ; immunology ; HLA-A2 Antigen ; immunology ; Humans ; Male ; Middle Aged ; Prostate-Specific Antigen ; immunology ; Prostatic Neoplasms ; therapy ; Protein Tyrosine Phosphatases ; immunology ; Treatment Outcome

Human Prostate Specific Membrane Antigen(PSMA) cDNA was amplified using total RNA extracted from prostate carcinoma tissue by RT-PCR. The cDNA fragment of extracellular domain of PSMA(edPSMA) gene was amplified by PCR and cloned into expression vector pMAL-c2x. Sequence analysis of both PSMA and edPSMA revealed identity to the GenBank reported. The edPSMA was expressed in E. coli as part of a fusion protein with MBP as the induction of IPTG. Western blot analysis showed the recombinant protein could react with PSMA monocloned antibodies 4G5. MBP-edPSMA fusion protein were purified by amylose resin affinity chromatography and showed to be homogeneity in SDS-PAGE(120 kD). BALB/C mice were immunized with the purified protein for the preparation of polyclonal antibody. The polyclonal antibody, which had a title of 1:12,800, were indicated the specificity to prostate tissue.
Animals ; Antibodies ; immunology ; Antibody Formation ; Antigens, Surface ; Carboxypeptidases ; biosynthesis ; genetics ; immunology ; isolation & purification ; Chromatography, Affinity ; methods ; Cloning, Molecular ; DNA, Complementary ; genetics ; Escherichia coli ; genetics ; Gene Expression ; Genetic Vectors ; Glutamate Carboxypeptidase II ; Humans ; Mice ; Mice, Inbred BALB C ; Protein Structure, Tertiary ; genetics ; physiology ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; instrumentation