X4 Pharmaceuticals, Inc.

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, a LifeSci advisor. Please begin.

Thank you, Operator, and good morning, everyone. Thanks for joining us. Presenting on today's call will be X4's Chief Executive Officer, Dr. Paula Regan, and the company's Chief Financial Officer, Adam Mostafa. Following prepared remarks by each, we will open up the call to your questions. And we'll be joined by Chief Scientific Officer, Art Tavares, Chief Medical Officer, Diego Kadovid, and Chief Operating Officer, Mary DiBiase. As a reminder, on today's call, the company will be making forward-looking statements regarding regulatory and product development plans, as well as research activities. 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. I'd now like to turn the call over to Paula Regan. Paula?

Thanks, Dan, and thank you, everyone, for joining us on the call this morning. where we plan to discuss our upcoming presence at the ASH December meeting along with highlights of the recent quarter and our financial results. In doing so, we hope to convey the level of excitement here at X4 as we head into what promises to be a very catalyst-rich period for the company. As we detailed in the press release that just went out, we have had all seven of our submitted abstracts accepted for publication at ASH, with four accepted to be presented as posters. This conference will be the largest presence ever for X4 at a medical meeting and represents the culmination of several years of incredibly hard work and success across our entire organization. We also just announced that we will be hosting an Investor Day on December 16th, just following the ASH meeting, to discuss the data in greater depth and to hear from a number of prominent key opinion leaders who will help put all of these data into context. So please save the date for that X4 event. The abstracts published today on the ASH website contain a very broad array of both clinical and scientific data, data that we believe not only further establishes XFOR as a leader in the CXCR4 space, but that also supports the broadening scope of the clinical potential of our lead candidate, Maverick XFOR. As you know, Maverick XFOR is the only CXCR4 antagonist being developed in an oral, once-daily formulation. We are currently conducting three clinical trials of Mavericks 4 across a number of indications. The first is our global pivotal phase 3 trial in people with WHIM syndrome. Importantly, we achieved a major milestone in early October, completing enrollment in this phase 3 clinical trial. Thirty-one adult and pediatric patients have been enrolled in the trial, which was originally designed to enroll 18 to 28 patients with WHIM syndrome. Top line data from this trial are anticipated in the fourth quarter of 2022. WHIM is a rare inherited primary immunodeficiency caused by a variety of mutations in the CXCR4 receptor gene that cause immune cell dysregulation. This dysregulation inhibits the proper maturation process for the entire range of white blood cells and causes them to get trapped in the bone marrow, preventing healthy trafficking and systemic circulation. This results in lifelong challenges to the health and well-being of WIM patients, including severe, recurrent, and sometimes life-threatening infections, loss of lung function and hearing, and significantly increased risk to HPV-associated cancers. By correcting this CXCR4 dysfunction, Mavericks 4 has been shown to not only increase the levels of circulating neutrophils, monocytes, and lymphocytes in WIM patients, but also to reduce the number and severity of annual infections and to reduce warts caused by unchecked HPV infections. One of our abstracts accepted for poster presentation at ASH further highlights similarly positive data from our ongoing Phase II open-label extension trial in patients with WHIM and includes patient interviews that reveal that all four of the continuing study participants experienced good tolerability and beneficial treatment effects when dosed with Mavericks before long-term. Also relating to WHIM, several of the abstracts published this morning focus on WHIM-causing CXCR4 mutation variants and on the U.S. prevalence of the disease. As quick background, there have been 16 WHIM-causing CXCR4 receptor mutations identified to date, all of which have been located in the internal tail, known as the C-terminus, of the receptor. Driven by our patient identification efforts in the PPAP collaboration and clinical trial screening efforts, we have identified a host of patients with both these known CXCR4 variants and also novel CXCR4 mutations. As a result, we have been able to better learn about the disease spectrum of WHIM, both clinically and genetically, and have established research that enables the correlation of a patient's WHIM symptoms with increased CXCR4 signaling caused by genetic mutations. This is referred to as genotype-phenotype correlation. In the abstract describing a novel variant, we specifically publish on our first discovery resulting from these efforts, which describe a novel missense mutation called D84H discovered in collaboration with treating physicians and X4 scientists. The D84H mutation is the first mutation identified outside of the C-terminus of the CXCR4 receptor. And we have shown through our internal research that this mutation causes gain-of-function signaling correlating with the disease phenotype of WIM patients. To look further into this newly identified mutation, we also analyzed multiple broad population genomic databases. which helped us determine that the allele frequency of the D84H mutation is very high in the generalized population. Using the current US population and a conservative estimate of 5 to 10% of individuals who go on to develop the disease symptoms, also known as penetrants, these data support that there are at least 1,250 to 2,500 WIM patients in the US resulting from the D84H mutation alone. We have found multiple D84H patients from different families across the world in the brief time since the discovery, which further validates this finding. We plan for further patient identification efforts to deepen the validation of the D84H prevalence estimate and to explore similarly identified CXER4 variants that could impact prevalence estimates in 2022 and beyond. Together, this patient identification and bench-to-bedside research along with our prior market research and our artificial intelligence research published in these ASH abstracts, continues to reaffirm our belief that WHIM is a significantly under-recognized and under-diagnosed condition, and that the true population may be much larger than is currently reported. We plan to go into more detail regarding our ongoing patient finding activities at our investor event in December, but needless to say, we are very encouraged by the results that our studies are elucidating building support and awareness to the rare disease physician community as we continue to ramp up our pre-commercial activities in advance of our expected phase three top line data, which, as I mentioned, are anticipated in the fourth quarter of 2022. Let's now shift to updates on our ongoing clinical trial in chronic neutropenia, which is an indication that nicely leverages our successful experiences with WHIM syndrome. our broader trial experiences, and input from our clinical communities. We believe the treatment opportunity for Mavericks 4 in chronic neutropenia is quickly becoming an additional key value driver for X4 based on new long-term data. Specifically, one of the ASH abstracts accepted for poster presentation demonstrates that Mavericks 4 alone or in combination with other therapies acutely and chronically increases total peripheral white blood cell counts 1.5 to 3 times baseline across a number of different diseases in both the presence and absence of the CXCR4 mutations. This suggests that Maverick Sephora could uniquely provide benefit to patients with broad chronic neutropenia conditions. And given its profile as an oral, once daily administration, we believe Maverick Sephora is positioned to potentially become standard of care in a treatment landscape only addressed currently by injectable therapies. Based on the extensive and long-term data we presented in the abstract, and based on input from our clinical advisors, we have amended our ongoing Phase 1b neutropenia trial to include a broader range of neutropenia conditions, including patients with severe and moderate neutropenia. We are now also enrolling all patients, whether or not they are being treated with the standard of care, which is granulocyte colony stimulating factor, or GCSF, and whether or not their neutropenia is caused by a genetic mutation. The trial is assessing the safety and tolerability of two weeks of dosing in cohort A and a single dose of Mavericks 4 in cohort B and measuring the effect of doses on patient neutrophil counts along with other white blood cell types. We've also modified the number of patients to be enrolled to 25, a number we believe will be sufficient to complete the goals of the trial. Our third ongoing trial with Mavericks 4 is designed to demonstrate safety dose and elucidate proof of concept in a rare B-cell lymphoma called Waldenstrom's macroglobulinemia. While greater than 90% of patients with Waldenstrom's have acquired mutations in what's called the MYD8 gene, a subset, about 30% to 40%, also have acquired mutations in CXCR4. There's a significant clinical unmet need in these double mutation patients, where the presence of the CXCR4 mutation, as with WIM patients, causes white blood cells, including their abnormal B cells, to become stuck in the bone marrow. This sequestration of cells can prevent patients from responding well to standard of care BTK inhibitor treatments. This can manifest as delayed response, inferior depth of response, and or shorter progression-free survival. Our Phase 1B trial is evaluating the safety and tolerability of Maverick for in-frontline and treatment refractory Waldenstrom patients at doses of 200, 400, and 600 milligrams in combination with ibrutinib. Both agents are delivered orally, once daily, in patients with confirmed NYDA8 and CXCR4 mutations. The study is also measuring change from baseline in IgM and hemoglobin, pharmacokinetics and pharmacodynamic markers, which include measurements of peripheral white blood cell counts in addition to measuring clinical response rates. As you may recall, this past June, we presented the first data from this initial trial in an e-poster at the 2021 European Hematology Association meeting. In the poster and on our investor call that day, we presented details from the first eight patients enrolled in the study. Those data were very encouraging with Mavericks for a plus abrutinib demonstrating good tolerability and biomarker data suggesting best-in-class potential for this combination treatment. Because the cutoff date for the ASH abstract filing was so close to this event and data announcement, the ASH, the abstract contains a fairly modest amount of incremental data beyond what we presented at EHA. As of the abstract cutoff date of June 15th, 2021, the overall response rate, which is minor response or better, in the eight patients evaluated at the time was 100%, with four of the eight patients achieving a major response, which is greater than a 50% reduction in CRM IgM, and one of the eight patients achieving a very good partial response, which is greater than a 90% reduction in CRM IgM. We do plan to have additional data at the ASH poster with a data cutoff of mid-October, and we look forward to a deeper reveal of overall response rates at the meeting and at our Investor Day in December. We remain very encouraged by our Waldenstrom's program potential as we continue to see encouraging signals emerging across patient groups within the Phase 1b trial. So as you can see, we are very excited about the data we've revealed so far and about the expanding potential of Mavericks 4, and we're really looking forward to our presentations at ASH and to our investor event just following the meeting. We'll be providing more details about the event in the coming weeks, but we currently expect it to be a two-hour virtual meeting on the morning of December 16th with participation from our expert clinical advisors. So please mark your calendars. With that update, I'll now turn it over to Adam to discuss our results for the quarter before we open up the call for questions.