X4 Pharmaceuticals, Inc.

Greetings, and welcome to X4 Pharmaceutical's second quarter 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 is being recorded. It is now my pleasure to introduce your host, Kerry Galan of LifeSci Advisors. 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 Reagan, and the company's Chief Financial Officer, Adam Mustafa. Following prepared remarks by each, we will open the call to your questions, and we will be joined by Chief Scientific Officer, Art Taveras, and Mary DiBiase, Senior Vice President, Technical Operations and Quality. 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 XCOR's most recent filings with the SEC. I'd now like to turn the call over to Paula Regan. Paula?

Thanks, Kerry, and thank you, everyone, for joining us on the call this morning as we update you on our significant clinical progress achieved so far this year and look ahead to what is expected to be a very productive remainder of the year. As I hope you saw in our release this morning, we provided a detailed update on our Mavericks IV clinical programs and highlights of upcoming events and milestones expected through the rest of 2021. For those of you new to the XIV story, Mavericks IV is our lead candidate. It is a first-in-class small molecule antagonist of the chemokine receptor CXCR4, a receptor involved in the healthy trafficking and maturation of immune cells. With its ability to develop and mobilize white blood cells out of the bone marrow, we believe Mavrixa4 has broad potential to provide patients benefits in a variety of immunodeficiency conditions and in certain cancers. Our lead indication of WHIM syndrome which is a rare inherited primary immunodeficiency disease caused by a variety of mutations to the CXCR4 gene, we announced this morning that we have now surpassed the 18-patient minimum enrollment that is needed for primary endpoint analysis and for U.S. regulatory filing. We have now enrolled 23 patients in the Phase III trial, enabling the study to also assess potential clinical benefit of Maverick before. We will be completing enrollment this quarter while allowing for the remaining identified patients to complete screening and potentially enroll in the trial. As a reminder, our 4WIM trial is a global, pivotal, phase 3, randomized, double-blinded, placebo-controlled, multicenter study designed to evaluate the safety and efficacy of Mavarixifor in genetically confirmed WIM patients over the course of 52 weeks. with an expected open label extension period to follow. The primary endpoint for the trial, time above threshold, absolute neutrophil counts, or TAT ANC, measures the level of circulating neutrophils in a 24-hour assessment relative to a clinically meaningful threshold in response to treatment with Mavericks IV versus the TAT ANC of treatment with placebo. Secondary endpoints assess infection rates, warp burden, markers of the immune system, and quality of life, among others. With enrollment now close to complete, we are confident that we will be positioned to announce top-line data from the trial in the fourth quarter of 2022 and, if successful, intend to file for U.S. regulatory approval in the first quarter of 2023. Based on this progress and on the encouraging data that continue to come out of the open-label extension of our ongoing Phase II trial in WHIM, more of which we plan to announce later this year, we are starting to ramp up our pre-commercial planning. In addition to the new Phase II data that I just mentioned, we also plan to provide further results from WHIM patient prevalence studies later this year, results that not only help in refining our estimates of the potential opportunity for Maverick support in the WHIM indication, but that also enrich our insights into market dynamics, patient identification, and physician awareness. Our research team in Vienna has also been doing innovative work to better understand and characterize the genetics underlying WHIM syndrome, fully developing a mouse model of WHIM, for example, examining the correlation between genotype and phenotype, and also identifying a new WHIM variant. We plan to announce preliminary findings from some of this work also later this year. Turning now to our program in Waldenstrom's macroglobulinemia, which you may recall is a rare blood cancer characterized by an excess of abnormal white blood cells in the bone marrow, we announced this morning that we have fully enrolled both cohort A and B in the study with six patients each. We are very pleased to have enrolled the minimum patients in the study needed to determine the maximum safest dosing in combination with ibrutinib. We are continuing to enroll patients in the optional cohort C to expand the total number of patients on study. As a reminder here as well, this is an ongoing Phase 1b open-label, multicenter, single-arm study examining intrapatient dose escalation, safety, pharmacokinetics, or PK, and the pharmacodynamics, or PD, of maverixifor at doses of 200, 400, and 600 milligrams in combination with abrutinib. a BTK inhibitor, and the current standard of care for patients with Waldenstrom's. Both agents are delivered orally, once daily, in patients with confirmed MYD88 and CXCR4 mutations. While greater than 90% of patients with Waldenstrom's have acquired mutations in the MYD88 gene, a subset, about 30 to 40%, have also acquired mutations in CXCR4. there's a significant unmet need in these double mutation patients where the presence of the CXCR4 mutation can prevent patients from responding well to ibrutinib monotherapy. This can manifest as delayed responses, inferior depth of response, and or shorter progression pre-survival. These patients typically experience greater cancer burden, higher serum IgM levels, and increased risk of developing a serious emergent condition called symptomatic hyperviscosity syndrome. In our phase 1B study, patients are being followed for adverse events and change from baseline IgM and hemoglobin, PK and PD markers, which include measurements of peripheral white blood cell counts in addition to measuring clinical response. This past June, we were very pleased to present the first data from this trial in an e-poster at the 2021 European Hematology Association meeting. In the poster and on our investor day call, we presented details from the first eight patients enrolled in the study. Those data were very encouraging, with maverixifor plus abrutinib demonstrating good tolerability with robust decreases in serum IgM at the low and mid doses of maverixifor, suggesting best-in-class potential for this combination treatment. We also saw meaningful increases in hemoglobin levels, suggesting reduction in cancer burden in the bone marrow. And at six months, patients achieved median IgM level reductions of 60 to 75 percent, with one patient achieving normal IgM and two of four patients achieving greater than 50 percent reductions in serum IgM from baseline. By the end of this year, we expect to announce additional data from this Phase 1B trial in Waldenstrom, including in safety and efficacy at the highest dose of 600 milligrams of Maverick before, as well as clinical response measures. Let's turn now to our ongoing clinical program in severe congenital neutropenia, or SCN, a rare blood disorder characterized by abnormally low levels of certain white blood cells called neutrophils. We are currently conducting a Phase 1B clinical trial in SBMs, and as enrollment is continuing to progress, we expect to be able to announce some initial data from the study in the fourth quarter of this year. Interestingly, as we've continued to assess Maverick support's mechanism of action and its ability to mobilize and develop neutrophils, data continue to emerge from prior and ongoing studies that show chronic, sustained white blood cell increases across a number of patient groups treated with maverick zephyr. As a result, we are beginning to explore the potential for broader use of maverick zephyr across the larger chronic neutropenia landscape. Our initial data in SCN as part of this broader data set may facilitate these larger opportunities for maverick zephyr in chronic neutropenias. and we aim to provide more details on these exciting efforts later this year. In summary, we could not be more pleased with our progress over the first half of 2021. Despite a global pandemic, we have been able to significantly advance Mavericks4 through key clinical development milestones with commercialization in sight. As we look ahead to what we expect to be a news-rich rest of 2021, We thank all of you for your support and look forward to providing frequent updates on our continued progress. With that update, I will now turn the call over to Adam to discuss our financial results for the quarter.