A Biomarker Study in Men With Localized Prostate Cancer Treated With Aglatimagene Besadenovec

This is a phase 2a, open-label, multi-center study evaluating aglatimagene besadenovec plus prodrug in men with localized, intermediate-risk prostate cancer who are planning to receive external beam radiation therapy (EBRT). Aglatimagene besadenovec is a replication-deficient adenoviral vector encoding the herpes simplex virus thymidine kinase (HSV-tk) gene. When combined with an oral antiviral prodrug (valacyclovir), this approach induces targeted tumor cell death and stimulates a systemic immune response. The study aims to characterize:

* Viral shedding and biodistribution of CAN-2409 genomes in blood, urine, and semen using validated qPCR assays. * Immune activation biomarkers, including lymphocyte subsets, cytokine profiles, and circulating tumor-related proteins.

Approximately 30 patients with intermediate risk prostate cancer will be recruited to the treatment arm and receive 3 courses of aglatimigene besadenovec by intraprostatic injection followed by orally administered valacyclovir. EBRT will start following the second injection. Biospecimens (blood, urine, semen) will be collected at specifed timepoints before and after each injection to assess biodistribution and immune response.

Approzimately 15 patients with intermediate risk prostate cancer will be recruited to the control arm receiving EBRT alone. Biospecimens (blood, urine, semen) will be collected at specified timepoints to assess immune response.

Safety will be monitored continuously. Frequency of treatment-emergent adverse events (TEAEs) and laboratory values will be evaluated for patients in the treatment arm. Patients in the control arm will be monitored for treatment-emergent serious adverse events suspected to be related to the collection of biospecimens.