Bill Rote
Analyst · William Blair. Your line is now open
Thanks, Steve, and good afternoon everyone. It's been almost three months since I've joined, and I'm delighted to be onboard and aiding in the advancement of our programs. One of the things that most attracted me to Retrophin is the incredible potential of the pipeline. We're in the fortunate position of advancing two first-in-class Phase 3 programs in rare disorders that currently have inadequate or no treatment options. I'm humbled by the opportunity to now guide these programs alongside a talented organization, and to build upon all of the great work that has already been completed. Let me start with Sparsentan. As mentioned, we had a very constructive and insightful End of Phase 2 Meeting with the FDA. Coming out of that meeting, we have a clear understanding regarding the outline of a Phase 3 trial that will us to move Sparsentan forward toward ultimate approval. As a reminder, this single pivotal trial will have pre and post-marketing elements comparing Sparsentan to Irbesartan, an angiotensin II receptor antagonist commonly used to treat FSGS in the absence of approved pharmacologic treatments. The pre-marketing element of the trial will contain an interim analysis measuring reductions in proteinuria. We expect this measurement to be similar to our secondly endpoint in the Phase 3 DUET trial, namely modified partially remission of proteinuria. Importantly, the DUET data showed that a significantly greater proportion of patients receiving sparsentan achieved modified partial remission of proteinuria compared to Irbesartan treated patients. This gives us confidence that we should be able to show a meaningful difference in the interim analysis during the pre-marketing phase of the pivotal trial, and ultimately file for Subpart H accelerated approval. The post-marketing confirmatory phase of this trial would continue to run over a longer period. This portion of the study is expected to measure reductions in estimated glomerular filtration rate, or eGFR. The purpose of the confirmatory phase is to tie the reductions in proteinuria seen in the interim analysis to an established and accepted endpoint, specifically changes in eGFR that reflects kidney health, and which is widely regarded as the best overall measure of kidney function in this setting. Currently, we are working to pull together a trial protocol encompassing the two phases that will best position the trial for clinical success. Working closely with our collaborators at Neptune, we have generated preliminary statistical analysis, which have given us great direction thus far. As many of you know, there is considerable heterogeneity in the injury pattern related to FSGS. To account for this in our statistical assumptions liking the interim analysis to our confirmatory endpoint, we're continuing to define the optimal statistical model. As Steve mentioned, we expect to have the protocol finalize and aligned with the agency in the second half of the year, and subsequently initiate our Phase 3 trial. Also note we will be simultaneously interacting with the EMA to ensure our protocol will ultimately support an EU filing. In parallel, our clinical operations team is working diligently to capitalize on the heightened excitement created by our positive Phase 2 DUET data presentations. As we noted previously, we've already selected more than a hundred sites with an estimated 1,600-plus subjects that have interest in participating in the trial. While our number one priority for Sparsentan is developing the protocol and launching this trial for FSGS, we are also exploring the ability to maximize the potential of this molecule by investigating its use in other glomerular nephropathies. Our initial diligence suggests that there may be a good fit in one or two other indications, and we look forward to finalizing our strategy after completing the FSGS protocol. Overall, we're excited about our momentum for Sparsentan, and we anticipate having a great deal more to discuss later this year. I'll now switch over to RE-024, our replacement therapy for PKAN. The program is moving along well, and we took all of the necessary steps during the quarter to ensure the first PKAN patients will be dosed this summer in our Phase 3 study, named FORT. FORT was designed under a special protocol assessment agreement to evaluate RE-024 for the treatment of PKAN. We anticipate that this trial will support regulatory filing in both the U.S. and EU. FORT will be an international randomized double-blind placebo-controlled study evaluating RE-024 in approximately 82 PKAN patients, ages six to 65 years. The primary endpoint of the trial will be the change in score of the PKAN activities of daily living scale from baseline through 24 weeks of treatment. The PKAN-ADL scale is an adaptation of part 2 of the comprehensive and widely-referenced unified Parkinson's disease rating scale, or UPDRS. We're excited to get the first PKAN patients dosed in the trial soon, and all is moving along as anticipated. As Steve mentioned earlier, sites have begun recruitment activities, and we have our U.S. investigator meeting this week. Finally regarding RE-024, all four patients receiving treatment as part of physician-initiated protocols outside the U.S. remain stable on therapy today. So in looking ahead to the balance of 2017, we have a number of clinical milestones that we are anticipating. Most notably, we're looking forward to finalizing our Phase 3 protocol for Sparsentan with the intent of initiating the trial towards the end of the year. We'll update on our development plans for additional glomerular nephropathies, and we'll be dosing our first patients in our pivotal trial of RE-024 and PKAN and ramping up enrolment throughout the end of the year. I look forward to sharing more about our progress as we reach these key milestones. Now, let me turn the call over to Neil for an operational update on the quarter. Neil?