The purpose of this study is to determine a safe, effective, and tolerable dose of PRX302 for the treatment of low to intermediate risk prostate cancer.

A multi-centre, open label, phase IIb study, evaluating the safety, tolerability and efficacy of a targeted intraprostatic focal administration in development. The study will treat approximately 40 men who meet the eligibility criteria, and give written consent. Safety and tolerability will be assessed post-treatment over 26 weeks. Efficacy will be assessed by biopsy and imaging (mpMRI) at 24 weeks.

Inclusion Criteria:

• Life expectancy ≥ 10 years.
• Serum prostate-specific antigen (PSA) ≤ 15ng/mL.
• A histologically proven, clinically significant lesion visible on mpMRI (magnetic resonance imaging) that is accessible to PRX302 transperineal injection.
• Radiological stage T1-T2 N0 Mx/M0 disease.
• Targeted prostate biopsy within 6 months prior to dosing, with a clinically significant lesion correlating with an mpMRI visible lesion.

Exclusion Criteria:

• Previous radiation therapy to the pelvis.
• Androgen suppression or anti-androgen therapy within the 12 months prior to dosing, for prostate cancer.
• Use of 5-alpha reductase inhibitor within the 3 months prior to dosing.
• Evidence of metastatic disease or nodal disease outside the prostate on bone scan or cross-sectional imaging.
• Inability to tolerate transrectal ultrasound (TRUS).
• Known allergy to latex or gadolinium (Gd).
• Prior rectal surgery preventing insertion of the TRUS probe.
• Any previous ablative procedures performed on the prostate, e.g., electroporation, radiofrequency ablation, high-intensity focused ultrasound (HIFU), cryosurgery, photochemical, thermal or microwave therapy to treat cancer of the prostate.
• Unable to have pelvic MRI scanning (severe claustrophobia, permanent cardiac pacemaker, metallic implant, etc., likely to contribute significant artifact to images).