Sophiris Bio Announces Complete Enrollment in Phase 2b Topsalysin Study of Localized Prostate Cancer

SAN DIEGO and VANCOUVER, British Columbia, Dec. 11, 2017 /PRNewswire/ -- Sophiris Bio Inc. (NASDAQ: SPHS) (the "Company" or "Sophiris") today announced that it has completed enrollment in its Phase 2b study to evaluate the safety and tolerability of topsalysin in treating men with clinically significant localized prostate cancer. Topsalysin (PRX302) is an innovative, first-in-class transmembrane pore-forming protein genetically modified to be activated only in the presence of enzymatically-active PSA, which is only found within the prostate.

"I am delighted that Sophiris has completed enrollment into its multi-center Phase 2b study. My thanks to the men and my colleagues in each clinical trial center for recognizing the potential of topsalysin to focally treat localized, clinically significant prostate cancer with a minimally invasive, targeted, short duration procedure," said Professor Hashim Ahmed, Chair of Urology, Imperial College London & Imperial College Healthcare NHS Trust and an investigator in the study. "Over the next few months, men in the trial will undergo follow-up biopsies of the prostate and, if necessary, may undergo repeat topsalysin dosing."

About the Phase 2b Study

The Phase 2b study is a multi-center, open-label, clinical study evaluating the safety and efficacy of targeted intraprostatic administration of topsalysin for the treatment of histologically proven, clinically significant, localized prostate cancer. The study utilizes previously obtained MRI images of each patient's prostate co-registered to real time 3D ultrasound to target the delivery of topsalysin directly into and around a pre-identified clinically significant tumor. The Company expects biopsy data from all patients dosed with the first administration of topsalysin to be available in the first half of 2018.  

Importantly, the Phase 2b study includes an option to re-treat patients with a second dose of topsalysin, with an additional targeted biopsy to occur six months following the second dose. In order to be eligible for a second dose, the patient cannot have experienced a clinically significant adverse event attributable to topsalysin or the dosing procedure from the first dose and the patient will need to have had a clinical response from the first dose but still have the presence of a clinically significant lesion area. Patients who have a complete response to the first dose will not receive a second dose. The Company expects to have final biopsy data on all patients who receive a second dose in the fourth quarter of 2018. 

About Localized Prostate Cancer

Prostate cancer is the second most common form of cancer in men in the US with an estimated 161,000 new cases in 2017. Approximately 80 percent of patients in the US are diagnosed with localized disease. Research has shown that patients with early, localized disease have a low likelihood of the cancer spreading beyond the confines of the prostate; however, many men with clinically significant localized disease choose to undergo radical treatment. Radical therapies include surgery to remove the entire prostate and/or radiation. Potential toxicities from radical treatments can be significant and permanent and include erectile dysfunction, urinary incontinence, and rectal toxicity.

About Topsalysin

Topsalysin (PRX302), an innovative, "First-in-Class" transmembrane pore-forming protein, was genetically modified to be activated only by enzymatically-active PSA, which is produced in large quantities within the prostate of men with prostate cancer. The targeted focal treatment of prostate cancer is in line with current treatment trends for solid tumors such as breast and liver, where the goal is to remove the tumor and preserve as much of the organ and organ function as possible.

Topsalysin has the potential to provide a targeted focal therapy for the ablation of localized prostate cancer lesions while potentially avoiding many of the complications and side effects associated with whole gland radical treatments. The increasing use of multiparametric magnetic resonance imaging (mpMRI) and advances in software to co-register previously obtained mpMRI images with real-time three-dimensional ultrasound images enables urologists to more accurately locate tumors within the prostate when taking biopsies. This increases the accuracy with which men with clinically significant lesions are identified. It also enables the injection of an ablative agent, such as topsalysin, directly into previously identified clinically significant tumors located within the prostate.  

About Sophiris

Sophiris Bio Inc. is a late-stage clinical biopharmaceutical company developing topsalysin (PRX302) for the treatment of patients with urological diseases. Topsalysin is in Phase 2 clinical development for the focal treatment of localized prostate cancer as well as Phase 3 clinical development for the treatment of the lower urinary tract symptoms of benign prostatic hyperplasia (BPH). Topsalysin is a highly potent ablative agent that is selective and targeted in that it is only activated by enzymatically active PSA which is found in high concentrations in the transition zone of the prostate and in and around prostate tumor cells. More than 400 patients have received treatment with topsalysin, which continues to appear to be safe and well tolerated. For more information, please visit www.sophirisbio.com.

Certain statements included in this press release may be considered forward-looking, including the quote of the Chair of Urology, Imperial College London & Imperial College Healthcare NHS Trust, expectations about clinical trial results, including the timing of expected results and expectations about further development of topsalysin. Such statements involve known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to be materially different from those implied by such statements, and therefore these statements should not be read as guarantees of future performance or results. Some of the risks and uncertainties that could cause actual results, performance or achievements to differ include without limitation, risks associated with clinical development, including the risk that enrollment will not be completed on the expected timeline, the results of the Phase 2b study will not be available when expected and risks that the results of the Phase 2b study will not replicate the results of the completed Phase 2a study of topsalysin for the treatment of localized low to intermediate risk prostate cancer or the study endpoint[s] will not be achieved, and other risks and uncertainties identified by Sophiris in its public securities filings with the SEC. All forward-looking statements are based on Sophiris' current beliefs as well as assumptions made by and information currently available to Sophiris and relate to, among other things, anticipated financial performance, business prospects, strategies, regulatory developments, clinical trial results, market acceptance, ability to raise capital and future commitments. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. Due to risks and uncertainties, including the risks and uncertainties identified by Sophiris in its public securities filings; actual events may differ materially from current expectations. Sophiris disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Company Contact:
Peter Slover
Chief Financial Officer
(858) 777-1760

Corporate Communications Contact:
Jason Spark 
Canale Communications 
(619) 849-6005 
jason@canalecomm.com 

SOURCE Sophiris Bio Inc.