Single intraprostatic bilateral injection of vehicle only

Qmax change from baseline at each individual post-baseline timepoint.

IPSS "responders" at each individual post-baseline timepoint.

Qmax "responders" at each individual post-baseline timepoint.

Proportion of patients who receive rescue therapy.

Time to onset of rescue therapy.

Incidence rate for episodes of urinary retention.

Transition Zone (TZ) prostate volume change from baseline as measured by transrectal ultrasound (TRUS) at each individual post-baseline timepoint.

Total prostate volume (PV) change from baseline as measured by TRUS at each individual post-baseline timepoint.

Treatment-emergent adverse events (TEAEs).

Episodes of acute urinary retention as determined by the independent Adjudication Panel.

Assessment of sexual function for men who are sexually active using the International Index of Erectile Function - Erectile Function (IIEF-EF) and the Male Sexual Health Questionnaire© short form for ejaculatory dysfunction (MSHQ-EjD).

Physical examinations.

Vital signs.

Electrocardiograms (ECGs).

Laboratory parameters, consisting of chemistry panel, complete blood count (CBC), and urinalysis.

Measurement of anti-PRX302 antibodies (APA).

Serum concentration of PRX302 only if clinically indicated by an event such as suspected systemic toxicity.