Sophiris Presents Positive Data from Phase 3 Study of LUTS Drug Treatment at AUA 2016

Sophiris Presents Positive Data from Phase 3 Study of LUTS Drug Treatment at AUA 2016

Sophiris Bio, Inc., presented positive data from its ongoing Phase 3 clinical trial of topsalysin — assessing the drug candidate as a potential treatment for symptoms of benign prostatic hyperplasia (BPH) — as a late breaking-poster at the recent 111th American Urological Association (AUA 2016)  annual meeting in San Diego, California.

The presentation, “Prospective, Randomized, Double Blind, Vehicle Controlled, Multinational, Phase 3 Clinical Trial of the Pore Forming Protein PRX302 for Targeted Treatment of Symptomatic Benign Prostatic Hyperplasia (The PLUS-1 Trial),” was delivered by Dr. Claus Roehrborn of  the University of Texas Southwestern Medical Center.

Topsalysin (PRX302) is a modified recombinant protein, engineered to be selectively activated by an enzyme in the prostate, leading to localized cell death and tissue disruption without damage to neighboring tissue and nerves. PRX302 is under development for the treatment of lower urinary tract symptoms (LUTS) of BPH, and as a treatment for localized low- to intermediate-risk prostate cancer.

The drug is specially engineered to be a single treatment for the long-term relief of LUTS, without the sexual dysfunction that might result from surgery. Its late-stage development was supported by the randomized, double-blind and placebo-controlled Phase 2b clinical trial (TRIUMPH), which had promising results. Data from TRIUMPH showed that patients treated with PRX302 had meaningful improvements in their International Prostate Symptom Score (IPSS) and urinary flow rate (Qmax) at three, six and 12 months.

PLUS-1 (NCT01966614) is an international, randomized, double-blind, and vehicle-controlled clinical trial to assess the efficacy and safety of a single transrectal intraprostatic injection of PRX302 as a LUTS treatment, compared to placebo. In total, 479 patients were enrolled at 75 different sites in six countries, and monitored for 52 weeks. Participants were randomized 1:1 to either PRX302 or placebo.

Data in the presentation covered the 92 percent of trial participants who have completed the monitoring period. Results showed a statistically significantly improvement in the International Prostate Symptom Score (7.6 point mean improvement) from baseline to week 52 in those receiving PRX302 compared to placebo. This primary endpoint was supported by secondary endpoints, including positive findings for peak urine flow and two disease-specific quality of life instruments.

PRX302’s toxicity was also reported to be mild, transient, and limited to irritative urinary symptoms (dysuria 20%, pollakiuria 10%, urinary retention 4%) and overall constitutional symptoms (fever 8%, chills 2%), primarily on the day of injection.

The study presentation concluded that “a single intraprostatic administration of PRX302 as a short, office-based procedure was well tolerated and produced clinically meaningful and sustained improvement in BPH LUTS,” adding that further trials are planned.

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