On October 21, 2019 Sophiris Bio Inc. (NASDAQ: SPHS) (the "Company" or "Sophiris"), a biopharmaceutical company studying topsalysin (PRX302), a first-in-class, pore-forming protein, in late-stage clinical trials for the treatment of patients with urological diseases, reported that following an End of Phase 2/ Pre-Phase 3 meeting with the United States Food and Drug Administration (FDA), there is agreement regarding the design of a single Phase 3 clinical trial to evaluate the potential of topsalysin as a targeted focal therapy to treat patients with intermediate risk localized prostate cancer (Press release, Sophiris Bio, OCT 21, 2019, View Source [SID1234542392]).
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
The Phase 3 study design agreed upon with the FDA is consistent with the design previously agreed upon with the European Medicines Agency, as reported in June of this year. The study will enroll approximately 700 patients with a confirmed diagnosis of localized intermediate risk disease, to be equally randomized to receive a single administration of either topsalysin or placebo. The primary endpoint for the study will be the proportion of patients at 12 months who have failed treatment, defined as histological progression of disease, resulting in the need for alternative therapy, as assessed by an independent central adjudication panel. In addition, the FDA has indicated that in order to receive approval, Sophiris will evaluate all patients that progress to alternative treatments for an additional 12 months, for a total of 24 months of data, post the administration of study drug.
"The meeting with the FDA was positive, confirming the proposed Phase 3 study design is an acceptable approach to targeted focal therapy in the proposed patient population. The FDA’s request to provide data on patients progressing to alternative therapy for an additional 12 months – for a total of 24 months – will, we believe, strengthen the overall data package for approval, providing valuable information on the durability of response following targeted focal therapy with topsalysin," said Professor Hashim Ahmed, Faculty of Medicine Department of Surgery & Cancer, Chair in Urology, Imperial College of London & Imperial College Healthcare NHS Trust and a member of the Scientific Advisory Board at Sophiris.
"The meeting with the FDA was productive and it was clear that if the proposed study were positive and the safety profile were to continue as observed in clinical trials to date, a single study has the potential to provide the clinical data to support regulatory approval in both the US and Europe," said Professor Scott Eggener, Faculty of Surgery and Radiobiology University of Chicago Medicine and a member of the Scientific Advisory Board at Sophiris.
"Now that there is a clear and agreed upon regulatory pathway forward for localized prostate cancer, we can now focus on our plan to fund this study and the Company going forward," said Randall E. Woods, our president and chief executive officer. "With the uncertainty of the regulatory pathway removed, we are advancing our discussions with multiple parties capable of funding the continued development of topsalysin."
About Localized Prostate Cancer
Prostate cancer is the second most common form of cancer in men in the United States with an estimated 175,000 new cases in 2019. Approximately 77 percent of patients in the United States 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.