X4 Pharmaceuticals, Inc.

Greetings and welcome to the X4 Pharmaceuticals First Quarter 2025 Financial and Operating Results Conference Call. At this time, all participants are in a listen-only mode. A question and answer session will follow the formal presentation. As a reminder, this conference call is being recorded. It is now my pleasure to introduce your host, Dan Ferry from LifeSci Advisors. Please begin.

Thank you, operator, and good morning, everyone. Presenting on today's call will be X-Force Chief Executive Officer, Dr. Paula Reagan, and Chief Financial Officer, Adam Mostafa. Following prepared remarks by each, we will open the call to your questions, and we'll be joined by Chief Commercial Officer, Mark Baldry, and Chief Medical Officer, Dr. Christoph Arbit Engels. As a reminder, on today's call, the company will be making forward-looking statements regarding regulatory and product development plans. These statements are subject to risks and uncertainties that may cause actual results to differ from those forecasted. A description of these risks can be found in X4's most recent filings with the SEC, including last year's Form 10-K and this past quarter's Form 10-Q, which is expected to be filed after market close today. Please note, that the X4 investor deck was updated this morning on the company website to include slides detailing some of the data analyses mentioned in this morning's press release and on this call today. I'd now like to turn the call over to X4's president and CEO, Dr. Paula Regan. Paula?

Thank you, Dan, and thanks to all of you for joining us this morning. The first quarter of 2025 was an extremely productive and value-building period for X4, with clinical trial advancement in chronic neutropenia, continued progress in the commercialization of Zolremdi for WHIM syndrome in the U.S., and our achievement of several significant milestones towards expanding the global potential of Mavericks 4 for patients. Let's begin with Mavericks 4 in chronic neutropenia, or CN. As you know, having successfully developed Mavericks 4, branded Zolremdi for patients with WHIM syndrome in the U.S., we are now also developing Mavericks 4 for the larger indication of chronic neutropenia. There are currently about 50,000 people diagnosed with some form of CN in the U.S. based on retrospective ICD-10 code analyses. Of those currently diagnosed with primary CN, we estimate that approximately 15,000 individuals, or about 30 to 40 percent, have remaining health challenges and continue to experience low absolute neutrophil counts, or ANCs, and recurrent infections despite available standard of care. We define this as the high unmet need CNN patient population. And it is with this population in mind that we are launching our ongoing FORWARD trial, a global pivotal phase three clinical trial evaluating the safety and efficacy of once daily oral maverick support in people with certain chronic neutropenic conditions, including primary autoimmune, idiopathic, and congenital neutropenia, and who are experiencing recurrent and or serious infections. As we reported on our last call, we're now screening and enrolling participants in over 20 countries with more than 90% of our target global trial sites being activated. Additionally, we've now finalized the trial design based on the feedback we also discussed previously from both the FDA and EMA to focus on those with the highest unmet needs, a population that matches up well with Mavericks for its targeted commercial CN patient population. The trial is enrolling with those with moderate to severe CN or ANC below 1,000 cells per microliter and experiencing two or more infections over the past 12 months. We also finalized the ANC response endpoint. The definition of ANC response is now uniform across all participants and is defined as an increase in ANC greater than 500 cells per microliter versus baseline ANC and occurring at 50% or more of the time points evaluated in the trial. The trial seeks to demonstrate statistically significant increases in ANC response and corresponding decreases in annualized infection rates between those on Mavericks 4 versus placebo. To date, the demographics of the enrolled population are balanced and representative of the target commercial CN patient populations, and baseline ANCs and historical infection rates are consistent with this high unmet need population. We recently completed some additional data analyses that further increase our confidence in the success of the forward trial. Individual patient data from both the Mavericks for Phase 3 4WIM trial and the completed Phase 2 CN trial have now been analyzed applying this just mentioned forward trial ANC response criteria. The full details of these analyses can be found in the updated investor deck that is on the front page of the investor section of our website. In summary, we created what we're calling heat maps, which detail individual ANC responses across all trial participants at all of the assessed time points. Specifically, the 4-WIM Phase III heat map provides a benchmark for ANC responses that translated into a 60% reduction in annualized infection rates when comparing Maverick support treatment to placebo. The CN Phase II heat map demonstrates the impact of Mavericks IV on durable increases in ANC across those with idiopathic, cyclic, and congenital chronic neutropenia. ANC outcomes in the CN Phase II trial look similar to ANC responses seen in the Mavericks IV arm of the 4WIM trial. When taken together, these heat map analyses provide evidence supporting the potential success of the CN Phase III trial where we believe that the expected ANC responses resulting from Maverick support treatment will correspond to a significant decrease in annualized infection rates. We also continue to believe that the forward trial is rigorously designed and powered to demonstrate the impact of Mavericks for NCM. The trial is powered at greater than 95% to assess the ANC response endpoint. and the 150 participant sample size independently supports robust powering at greater than 90% for the infection rate results. As of today, we continue to anticipate full enrollment in the trial in the third or fourth quarter of 2025, which would enable disclosure of top line data in the second half of 2026. Lastly, on the CN front, we have good news from the U.S. Patent Office. We received a notice of allowance on our application, which claims include the use of Mavericks for and treating severe chronic idiopathic and autoimmune neutropenia in patients without a CXCR4 genetic variant. The patent is expected to expire in the US in March of 2041. Similar patent applications are pending in Europe, China, Japan, and Canada. To conclude, we remain confident that we'll be able to deliver on our upcoming milestones in CN, that we'll have a long-term patent protection in the indication, and that the value proposition for Mavericks IV in CN could represent a $1 to $2 billion opportunity in the U.S. alone. With that, let's turn now to our progress with Mavericks IV in WHIM syndrome. At the end of March of this year, cumulative sales of Zolrembi reached 3.5 million since our mid-May launch last year. This quarter's sales were slightly lower than those reported in the fourth quarter because of the fluctuations in the timing of inventory resupply, which causes some lumpiness to sales. This is typical with markets anchored in small patient populations and early in launch. We do expect this to even out over time with the increasing demand that we're already seeing. We are currently in the thick of conference season and continue to have fruitful engagements with all of our targeted top-tier immunologists and hematologists, increasing the visibility of WIMP syndrome. And we're seeing success in our educational efforts that support HCPs and finding WIMP patients, with new patients now representing approximately 40% of our current Zol Remedy-treated population at the end of the first quarter. In addition, we're just about to kick off our WHIM Patient Ambassador Program and hope these efforts will continue to build demand for Zil Remedy in the U.S. As we discussed on our last call, we made significant progress in our efforts to expand the potential global reach of Maverick score in WHIM during the first quarter. In January, we announced that our submitted MAA was accepted by European regulatory authorities for review. With a typical 12 to 15-month review process, we anticipate potential approval from the EMA as early as the first quarter of 2026. We also announced the completion of two international partnerships in the first quarter, the first with Nourgine, a leading European specialty pharmaceutical company, to commercialize Mavericks for Europe, Australia, and New Zealand. Norgene will be launching Maverick support for the WIM indication in the EU should we receive approval there next year, and we are working closely with them to ready for that possibility. The second partnership is with Taba Rare, another specialty pharmaceutical company to commercialize Vol Remedy in the Middle East and North Africa, or MENA region, following any approvals there. The MENA region does have a compassionate use program that allows physicians to prescribe drugs approved in other countries to local patients with no other treatment options. We'll keep you updated on our progress there. Lastly, we're continuing to advance the understanding of WHIM syndrome, as well as the impact of Mavericks 4 on the disease. We had two abstracts accepted for publication at the annual meeting of the Clinical Immunology Society, or CIS, which starts today. From the 4-WIM Phase III Open Label Extension, or OLE, we'll be presenting two-year data that demonstrate a marked clinical improvement in wart severity as assessed by a standard measurement, the clinical global impression of severity across 70 defined wart areas. We're also presenting results from the first-ever survey looking into infection burden in WIM patients. Twenty WIM patients provided responses. None were on Zolrembi at the time. The survey revealed that 60% of those under 18 years and 73% of those 18 or over reported experiencing at least one infection in the previous three months, with 25% requiring overnight hospitalizations due to infection. The study concludes that, quote, the frequency and severity of infections requiring medical care and hospitalizations underscores the urgency to proactively treat patients with WHIM syndrome. Needless to say, we're very proud to be able to have developed this first approved therapy for WHIM in the U.S. and look forward to commercial updates and continued global advancement milestones in the coming quarters. I'll now turn it over to Adam to run through our financials. Adam?