Simon Pimstone
Analyst · Stifel
Thank you, Jodi, and good afternoon, everyone. We've now passed the midpoint of the year. And as I reflect on our progress, we remain on track to reach our stated goals for 2019, advancing our robust pipeline of neurology-focused product candidates, including XEN496, XEN1101, XEN901 and XEN007 with multiple products in Phase II or later-stage development by the end of this year. Today, I'll provide an update on each of our clinical stage programs and highlight some of the important milestone events anticipated this year before opening up the call for questions at the end of Ian's financial commentary. Let me begin with XEN496, a Kv7 potassium channel modulator we're developing as a treatment for a rare pediatric neuro developmental disorder called KCNQ2 developmental and epileptic encephalopathy, or KCNQ2-DEE, and is also sometimes referred to as EIEE7. XEN496' active ingredient is ezogabine, which was previously approved by the FDA as a treatment for adult focal epilepsy but was withdrawn from the market for commercial reasons. However, published noncontrolled clinical studies as well as anecdotal parental and physician feedback suggest that ezogabine may be an efficacious and generally well-tolerated therapy for KCNQ2-DEE, with potential to improve development and cognition as well as to reduce seizure burden. We recognize that in order to develop XEN496 for this pediatric population, we would need to take a number of important steps. We obtained orphan drug designation, or ODD, from the FDA for XEN496 as a treatment for KCNQ2-DEE. We submitted a pre-IND briefing package with our proposal to study XEN496 in infants and children with KCNQ2-DEE with appropriate safety monitoring. In response, the FDA supported our proposed safety monitoring plans, including long-term follow-up to monitor potential side effects, and indicated that a single small pivotal trial could be sufficient, provided we see substantial evidence of effectiveness in KCNQ2-DEE. We also needed to address the formulation challenges of ezogabine since the original hard-coated tablet was unsuitable for administration to children. It is difficult to cut the coat of tablet precisely and obtain an accurate dose. In addition, ezogabine may be unstable in solution when compounding, and parents have reported the compounded ezogabine would discolor. Xenon has developed XEN496 with a focus on addressing these challenges. We have made excellent progress over the past few months and now have a final pediatric friendly formulation to advance into clinical testing. The XEN496 final drug product is a granule formulation packaged as single-dose sachets. Parents or caregivers would tear open one sachet and disperse the granules into the chosen semisolid or liquid food carrier. We designed the formulation with the goal of making certain that XEN496 does not have an objectionable taste or mouth feel, is comparable with standard carrier systems including plastics and that XEN496 does not discolor as a granulated form. We believe our formulation has major product advances over the prior ezogabine tablets and, in addition, may provide us with commercial exclusivity well beyond the orphan exclusive 7.5-year term. Standard in vitro testing has shown that XEN496 acts as an immediate release drug like ezogabine with essentially overlapping the solution curves. We have also completed animal in vivo pharmacokinetic or PK studies. And again, XEN496 is performing as expected, with PK similar to what was observed with ezogabine. The testing done to date gives us a high degree of confidence to move this final formulation into clinical development and long-term stability studies, which are now underway. In order to ensure XEN496 is providing adequate drug exposure in humans, we will test this granule formulation in a PK study of healthy adult volunteers, which is expected to be initiated later this quarter. We thereafter intend to file an investigational new drug or IND application in the fourth quarter to support the initiation of a Phase III clinical trial in KCNQ2-DEE. We continue to support initiatives that may help us in our development and may help patients with rare forms of epilepsy, such as KCNQ2-DEE. As noted previously, we are a sponsor of the Behind the Seizure program in the U.S. and Canada to provide no cost testing of children up to 60 months of age with seizures. This access to genetic testing allows for the identification of the cause of seizures and the implementation of specific treatment in many cases. This information helps to build a database of physicians treating these rare disorders. And additionally, patients may be identified for relevant clinical studies. Recently, we were invited to participate in an educational webinar hosted by a patient advocacy group called the KCNQ2 Cure Alliance. We, along with a well-known neurologist in this field, Dr. John Millichap, provided some background on drug development for rare pediatric epilepsies, delivered a status update on XEN496, answered questions submitted by parents in a panel discussion and discussed an upcoming Xenon-sponsored patient survey. Data from this survey, which will gather feedback directly from caregivers of children with KCNQ2-DEE, will be extremely useful and will help inform the clinical trial design for a planned Phase III trial in KCNQ2-DEE. We have also identified other diagnostic companies and academic consortia to expand our reach to identify as many KCNQ2-DEE cases as we can, both for our upcoming clinical trial as well as for future commercial reasons. To date, through our interactions with diagnostic companies, we are aware of approximately 800 genetically diagnosed cases. In addition, a recent epidemiological study from Europe reported a KCNQ2-DEE birth rate of approximately 1 in 17,000, not far off Dravet Syndrome, which has been reported as approximately 1 in 12,000 to 1 in 15,000 births. Based on this information, we believe that KCNQ2-DEE may be more common than initially thought. We expect to put more diagnostic partnerships in place to support our planned Phase III trial and beyond. We believe given our precision approach as well as our planned administration in the very young, XEN496 in its new pediatric formulation offers children with KCNQ2-DEE a promising chance of seizure control as well as a chance at disease modification, something not yet observed with any AED. Next up in our pipeline is XEN1101, a differentiated next-generation Kv7 potassium channel modulator being developed for the treatment of epilepsy and potentially other neurological disorders. Site selection and patient enrollment for our XEN1101 Phase IIb clinical trial are currently underway in the United States, Canada and Europe. The trial is designed as a randomized, double-blind, placebo-controlled multicenter study to evaluate the clinical efficacy, safety and tolerability of XEN1101 administered as adjunctive treatment in adult patients with focal epilepsy. Approximately 300 patients will be randomized in a blinded manner to 1 of 3 active treatment groups or placebo in a 2:1 to 1:2 fashion using doses of XEN1101 of 25, 20 and 10 milligrams plus a placebo arm. The primary endpoint in this trial is the median percent change in monthly focal seizure frequency from baseline compared to treatment period of active versus placebo. To date, feedback from sites is promising. There is strong interest in the XEN1101 study as investigators support this Kv7 mechanism of action in epilepsy. And XEN1101 would represent an only drug in class if approved. Furthermore, there is not a significant burden of competing trials at the moment. Long-term 6- and 9-month toxicology studies are underway and are expected to support the planned 12-month open-label extension for patients enrolled in the Phase IIb clinical trial. Depending on the rates of enrollment, top line results are anticipated in the second half of 2020. Turning to the third product in our pipeline, XEN901, a potent, highly selective Nav1.6 sodium channel inhibitor being developed for the treatment of epilepsy. We have completed a randomized double-blind, placebo-controlled Phase I clinical trial to evaluate XEN901's safety, tolerability and PK in both single-ascending and multiple-ascending dose cohorts of healthy adult subjects and included a pilot TMS arm. As with XEN1101, the observed changes in TMS-EMG and TMS-EEG parameters suggest activity of XEN901 in the target CNS tissue. We received important feedback from the FDA regarding the requirements to support advancing XEN901 directly into a pediatric clinical trial, examining its efficacy in pediatric patients with SCN8A epileptic encephalopathy, otherwise known as SCN8A-EE. Similar to XEN496, we recognize the need to create a pediatric friendly formulation of XEN901, and we recently completed development of a granule formulation with compelling in vitro and in vivo characteristics. We are also in the process of completing juvenile toxicology studies to support pediatric development activities. Again, mirroring the path of XEN496, we intend to run a PK study in healthy adult volunteers with the new XEN901 pediatric formulation beginning in the third quarter of this year, followed by an IND submission to start a proposed clinical trial in SCN8A-EE patients thereafter. We look forward to keeping you updated on our progress over the coming quarters. The fourth clinical stage product in our neurology pipeline is XEN007, with the active ingredient flunarizine. XEN007 is a CNS-acting calcium channel modulator that modulates Cav2.1 and T-type calcium channels. Other reported mechanisms include dopamine, histamine and serotonin inhibition. Available in certain countries outside of the United States, flunarizine has been reported to have clinical benefit in treating migraine and other neurological disorders, including hemiplegic migraine or HM, alternating hemiplegia of childhood or AHC, vertigo, and as an adjunctive treatment in certain epilepsies, including childhood absence epilepsy or CAE. The FDA granted us a rare pediatric disease designation for the treatment of AHC with XEN007 and previously granted orphan drug designation for XEN007 as a treatment of both AHC and HM. In addition, we entered into key licensing and manufacturing agreements to support the advanced clinical development of XEN007. Various development strategies for XEN007 are under consideration, given the well-understood efficacy and safety profile of flunarizine, we continue to have discussions with a number of physicians who have expressed an interest in running investigator-sponsored clinical trials. In the near term, we anticipate the initiation of a Phase II investigator-led open-label clinical trial examining the potential clinical efficacy, safety and tolerability of XEN007 as an adjunctive treatment of childhood absence epilepsy. Flunarizine has demonstrated efficacy in preclinical absence seizure models, which produce seizures characteristics that are consistent with human absence seizures. Both as a monotherapy and as a combination therapy, flunarizine significantly reduced the number and duration of spike wave discharges on EEG when compared to standard of care medicines, including valproic acid or ethosuximide alone in these preclinical models. With a mechanism of action that is differentiated from other calcium channel blockers, coupled with a vast amount of safety and clinical data generated with flunarizine, we believe XEN007 may potentially offer a better alternative for treating CAE than other antiepileptic drugs currently available. We look forward to providing more details when this Phase II study is up and running. My status update today reflects our excitement with the continued advancement of the clinical stage therapeutic products within our neurology-focused pipeline, including our progress advancing XEN1101 in our large adult focal epilepsy Phase II trial. We also look forward to conducting the important PK studies that I mentioned so that we can test our new pediatric formulations prior to initiating clinical trials in rare pediatric disorders such as KCNQ2 or SCN8A encephalopathic epilepsies. Now I'd like to turn the call over to Ian, who will briefly recap our financial position and will provide some summary commentary before opening up the call to your questions. Ian?