X4 Pharmaceuticals, Inc Q1 FY2024 earnings call

• Approval of XOLREMDI (mavorixafor) for WHIM syndrome in US, with Phase III trial results published in Blood and OLE showing durable improvements. - Market size estimate of at least 1,000 confirmed WHIM patients in US. - Plans for European regulatory submission of XOLREMDI and development of mavorixafor for chronic neutropenia. - Phase II trial in chronic neutropenia with enrollment complete, planning investor event in late June to present interim results, and aiming to present final Phase II data later in the year. - Financials: Cash of $81.6 million as of March 31, 2024; R&D expenses $19.9 million, SG&A expenses $17.4 million, net loss $51.8 million for Q1 2024.

No traditional product segment financial performance detailed; focus on company's product development and financials.

• Intention to initiate Phase III chronic neutropenia trial this quarter. - Plan to present interim results from Phase II chronic neutropenia trial at investor event in late June. - Aim to present final Phase II chronic neutropenia data later in the year and potentially at a major medical conference. - Cash position of $81.6 million sufficient to support operations into 2025, excluding potential monetization of PRV from XOLREMDI approval.

• Risks associated with forward-looking statements regarding regulatory and product development plans. - Uncertainties that may cause actual results to differ from forecasted due to various factors.

Q: Looking forward to the update next month, could you remind on how infections are defined in Phase III and if prior infections are adjudicated?

A: Christophe Arbet-Engels explained that infections are adjudicated by the safety committee, with patients reporting adverse events, antibiotic use, and hospitalizations related to infections, and prior infections in the past year are defined by criteria like antibiotic use and hospitalization.

Q: How is the statistical plan for Phase III accommodated for potential reduction in infection rates in placebo arm?

A: Christophe Arbet-Engels stated the study is randomized, designed with experts to have over 90% power for infection rates, taking conservative assumptions on effect size.

Q: On launch parameters for XOLREMDI, what information will be provided?

A: Mark Baldry mentioned field teams are out, engaging with physicians in different buckets (aware of WHIM, not familiar, not aware), and will communicate progress to the Street over time.

Q: On chronic neutropenia, about bone pain from G-CSF, what's the data and how it helps commercial setting?

A: Christophe Arbet-Engels said bone pain is a real issue with G-CSF, and studies will look at decreasing G-CSF usage and its impact on patient lifestyle, with Phase II/III studies helping in commercial setting.

Q: On Phase III chronic neutropenia, what's the expectation of data in upcoming update and split of patients?

A: Paula Ragan said data will be in context of ANC increases, durability of counts, and applying Phase III criteria success to Phase II subset to build confidence. Details on follow-up and patient split were discussed with clarification needed on the question.