Wilson Therapeutics presented positive final Phase 2 data for WTX101 at EASL Annual Meeting

Apr 24, 2017

Wilson Therapeutics AB (publ), announced today that the final data from the company’s Phase 2 trial of WTX101 (bis-choline tetrathiomolybdate), an investigational first-in-class copper modulating agent with a unique mode of action for the treatment of patients with Wilson Disease, were presented as a late breaker presentation at The International Liver Congress™ 2017. The congress is the Annual Meeting of the European Association for the Study of the Liver (EASL), held in Amsterdam, the Netherlands, 19 – 23 April. The data were presented by Prof. Karl Heinz Weiss, MD, University of Heidelberg. The presentation included the final results of all hepatic parameters studied in the Phase 2 study of WTX101, as well as copper control and neurological outcomes over the course of the study. As previously reported, the Phase 2 study of WTX101 met its primary endpoint of copper control (p< 0.001). 

WTX101-201 was a 24-week open-label Phase 2 study evaluating the efficacy and safety of WTX101 monotherapy in 28 adult newly-diagnosed patients with Wilson Disease, who had received either no prior treatment for Wilson Disease or a standard of care agent for up to two years. All patients who successfully completed the 24-week study period elected to stay on WTX101 in an extension phase of the study. 

“There is a significant need for improved Wilson Disease therapies, especially when it comes to rapid control of free copper, initial response rates, a benign safety profile and a simplified dosing regimen”, said Professor Weiss. “The data presented at EASL show that WTX101 has the potential for a strong and fast effect on free copper, normalizing the levels within 12 weeks. This also seems to translate into a clear clinical benefit for the patients as we also see a high response rate on clinical symptoms. As WTX101 can be taken once daily it also has the potential to significantly improve treatment compliance which is a major concern in the everyday clinical setting, and which often leads to poor clinical outcomes. All in all, this is very encouraging for the Wilson Disease community.” 

“The data from the Phase 2 study also demonstrate that WTX101 is generally well-tolerated with few patients reporting gastro-intestinal intolerance or skin reactions which are common side effects in the clinical setting today”, commented Carl Bjartmar, MD, PhD, Chief Medical Officer of Wilson Therapeutics. “Additionally, we are very pleased the treatment improved the patients’ neurological status and self-reported disability, and that we have not observed any case of drug induced neurological worsening upon initiation of WTX101, which is a serious side effect that may occur with existing treatments.”  

The primary endpoint, defined as achieving or maintaining normalized levels of less than 2.3 µM of free blood copper, or reaching a reduction of at least 25% in free copper in blood from baseline after 24 weeks of treatment, was met by 71% of the patients (p< 0.001). Free copper in blood was measured as non-ceruloplasmin bound copper, corrected for the amount of copper bound to tripartite tetrathiomolybdate-Cu-albumin complexes. In the ITT population, WTX101 monotherapy reduced mean serum free copper by 72% (p< 0.0001) at week 24 compared to baseline. Mean serum free copper levels were reduced below the upper limit of normal after 12 weeks of treatment.  

Secondary endpoints included various hepatic and neurological measures. Liver function, as measured by INR, albumin and modified Nazer score, remained stable at week 24. Liver status, as measured by Model for End-Stage Liver Disease (MELD), was also unchanged throughout the study, indicating stabilization. Neurological disability and status were measured as Unified Wilson Disease Rating Scale (UWDRS) part 2 and 3 respectively. Significant neurologic improvements from baseline to week 24 were observed in patients’ disability (p< 0.001) and neurological status (p< 0.0001).   

Treatment with WTX101 was generally well tolerated with most reported adverse events being mild (grade 1) to moderate (grade 2). Reversible early liver transaminase elevations were reported in 39% of patients. These elevations were generally mild to moderate, asymptomatic and normalized with dose adjustments. No initial neurological worsening upon initiation of WTX101 was observed. 

“We are very pleased with the clinical progress of WTX101,” stated Jonas Hansson, CEO of Wilson Therapeutics. “We believe WTX101 has the potential to address many of the unmet needs in Wilson Disease and we are now working hard to finalize the preparations for initiating a Phase 3 trial during the second half of the year.” 

About WTX101-201
WTX101-201 is a 24-week open-label Phase 2 study evaluating the efficacy and safety of WTX101 monotherapy in 28 newly-diagnosed patients with Wilson Disease, aged 18 years and older, who had received either no prior treatment for Wilson Disease or a standard of care agent for up to two years. Patients recruited in the study had various degrees of hepatic impairment at the time of enrollment and the majority also had neurological symptoms at study start. The study was conducted at 11 sites in the U.S. and Europe. Patients received WTX101 at individualized doses between 15 and 120 mg/day. The primary endpoint was defined as achieving or maintaining normalized levels of less than 2.3 µM of free blood copper, or reaching a reduction of at least 25% in free copper in blood from baseline, after 24 weeks of treatment. Free copper in blood was measured as non-ceruloplasmin bound copper, corrected for the amount of copper bound to tripartite tetrathiomolybdate-Cu-albumin complexes in blood. Secondary endpoints included reduction of serum free copper from baseline, neurological disability and status measured as Unified Wilson Disease Rating Scale (UWDRS) part 2 and 3 respectively, liver status measured as the Modified Nazer Score and quality of life measured through EuroQOL 5 Dimensions (EQ5D). 

About WTX101 (bis-choline tetrathiomolybdate)
WTX101 (bis-choline tetrathiomolybdate) is a first-in-class copper modulating agent with a unique mechanism of action, under investigation as a novel therapy for Wilson Disease. WTX101, unlike current treatments for Wilson Disease, exhibits a specific copper buffering activity and acts in the liver where it removes copper from the overloaded copper buffer. WTX101 also rapidly neutralizes toxic free copper in tissue and blood by forming complexes with excess copper and albumin. The excess copper is excreted via the bile, the body’s natural route for excess copper elimination. 

A Phase 2 study evaluating the efficacy and safety of WTX101 in Wilson Disease patients was successfully completed in 2016. In addition, the active ingredient of WTX101, tetrathiomolybdate, has been tested in several previous clinical studies in Wilson Disease patients.  The data from these studies suggest that WTX101 can rapidly lower and control toxic free copper levels and improve clinical symptoms in these patients. The data also suggest that WTX101 is generally well-tolerated and may have potential for a reduced risk of neurological worsening after initiation of therapy. WTX101 is expected to have a once-daily dosing regimen which may potentially translate into improved compliance in Wilson Disease patients, leading to fewer treatment failures and ultimately improved outcomes as a result. WTX101 has received orphan drug designation for the treatment of Wilson Disease in the US and EU. 

About Wilson Disease
Wilson Disease is a rare genetic disorder of impaired copper metabolism that causes serious copper poisoning. The genetic defect severely affects the body´s ability to regulate copper balance, resulting in life-threatening damage to the liver, the brain and further organs if left untreated. Wilson Disease affects approximately one in every 30,000 people worldwide, corresponding to a prevalence of approximately 10,000 patients in the US and 15,000 patients in the EU. The therapies currently being used in Wilson Disease were introduced in the 1950’s and 60’s and since then there have been no new treatment options developed for patients with this disease. 

About Wilson Therapeutics
Wilson Therapeutics is a biopharmaceutical company, based in Stockholm, Sweden, that develops novel therapies for patients with rare diseases. Wilson Therapeutics’ lead product, WTX101, is in development as a novel treatment for Wilson Disease. A Phase 2 clinical study has been successfully completed and preparations for a pivotal Phase 3 study are ongoing. Wilson Therapeutics is listed in the Mid Cap segment on Nasdaq Stockholm with the stock ticker WTX.

 Visit www.wilsontherapeutics.com for more information.

 
For further information contact:

Jonas Hansson, CEO, Wilson Therapeutics AB
Telephone: +46 8 796 00 00
Email: jonas.hansson@wtx.se 

Wilson Therapeutics AB (publ)
Org nr 556893-0357
Kungsgatan 3
SE-111 43 Stockholm

  
The information in the press release is information that Wilson Therapeutics is obliged to make public pursuant to the EU Market Abuse Regulation. The information was submitted for publication, through the agency of the contact person set out above, at 08.00 CET on 24 April, 2017.