Paula Ragan
Analyst · Stifel. You may proceed with your question
Thanks Dan, and thank you everyone for joining us on the call this morning. Let me start by saying that we could not be more pleased with our accomplishments so far this year. We've achieved significant progress and our mavorixafor clinical programs and successfully completed a $55 million at-the-market PIPE financing to included participation from leading biotech investors, both new to X4 as well as from existing investors. We believe this demonstrates a strong level of investor conviction and the clinical and commercial potential of mavorixafor, while also extending our expected cash runway into late 2022 and supporting our additional pipeline programs. As mentioned on our last call, the pace of enrollment in our key clinical programs has ramped up significantly since last year. Specifically, we now expect to be able to announce an important enrollment update in our Phase 3 trial in WHIM syndrome in mid-2021. As a reminder, WHIM is a rare inherited primary immunodeficiency disease caused by gain of function CXCR4 mutations that prevent healthy immune cell trafficking and effective immuno surveillance. Most patients with WHIM disease have life on neutropenia and lymphopenia, that can result in a variety of serious chronic infections across multiple organ systems, HPV associated regions and increased cancer risk and other serious life impacting morbidities. Mavorixafor is our first-in-class small molecule antagonist of the CXCR4 receptor that we believe has the potential to be the first disease modifying therapy for more than 3500 potential diagnosed and undiagnosed WHIM patients in the U.S. The 4WHIM Phase 3 trial is a global randomized, placebo controlled double blinded, multicenter study designed to evaluate the safety and efficacy of mavorixafor over a course of 52 weeks, and approximately 18 to 28 genetically confirmed WHIM patients. The Phase 3 primary efficacy endpoint, called time above threshold for absolute neutrophil count, or TATANC, compares the level of circulating neutrophils relative to a clinically meaningful threshold in response to mavorixafor treatment versus placebo. As you may recall from our Phase 2 study and published in the journal blood in 2020, mavorixafor demonstrated greater than a 600% increase in time above threshold for neutrophil counts at our selected Phase 3 dose as compared to the lower doses treated for WHIM patients, which gives us deep confidence and the potential success of our Phase 3 study. Secondary endpoints include infection rates, work burden and assessment of immune system function and quality of life among others. At our current rate of enrollment, we continue to expect top line data from this Phase 3 trial in 2022. We also continue to expect to report new data from the open label extension of our Phase 2 clinical trial and WHIM later this year. We expect these data will continue to provide us insights regarding the long-term safety and durability of chronic mavorixafor treatments. Additionally, we anticipate several scientific publications that further support mavorixafor mechanism of action and potential for disease modification, as well as demonstrate its breadth of activity across a spectrum of WHIM genotypes. Finally, we look forward to sharing new information regarding our additional WHIM prevalence research later this year. In addition to our WHIM program, we continue to make good progress in our Phase 1b trial for the treatment of Waldenstrom's macroglobulinemia. A rare form of Non-Hodgkin's Lymphoma. As a reminder, this Phase 1b study is a multicenter open label, dose escalation clinical trial that is expected to enroll approximately 12 to 18 patients. We are very excited to have recently received notice of acceptance of our Phase 1b trial abstracts for a poster presentation at this year's annual Congress of the European Hematology Association or EHA that will be taking place virtually from June 9 to June 17. The abstract and poster will focus on initial clinical data from the ongoing Phase 1b trial of mavorixafor at the study low and mid doses in combination with an ibrutinib and the subset of Waldenström's macroglobulinemia patients harboring both the MYD8 and CXCR4 mutations. In addition to safety pharmacokinetics and pharmacodynamic markers, the initial data set will evaluate changes in Serum immunoglobulin M, or IgM and blood hemoglobin levels. It is well established that reductions in IgM levels and increases in hemoglobin levels correlate favorably with clinical responses for the treatment in Waldenstrom's patients. Later this year, we expect that the study will mature further, such that we should be able to present data sets regarding the determination of the final dose selection for further study and assessment of major response rates, as well as ongoing safety across a range of doses. So as you can see, 2021 has been quite productive for us to-date, and we're looking forward to a steady flow of value adding data presentations and business milestones throughout the rest of the year. With that update, I will now turn the call over to Adam to discuss our results for the quarter and our recent financing announcements. Adam?