X4 Pharmaceuticals, Inc. Q3 FY2024 earnings call

Operational Achievements

• U.S. FDA approval in late April 2024 for XOLREMDI for WHIM syndrome.
• Engaged with all 3,400 targeted immunologists and hematologists for XOLREMDI launch. Market research shows >75% knowledge of WHIM syndrome among targeted prescribers and 80% of HCP would consider prescribing XOLREMDI.
• Phase II study of mavorixafor in chronic neutropenia (CN) completed: mavorixafor monotherapy increased and durably sustained absolute neutrophil count (ANC) to normal range; combination with G-CSF allowed downward adjustment of G-CSF dose while maintaining normal ANC; neutrophils mobilized by mavorixafor are functional.
• Phase III trial (4WARD) in CN progressing well: 85% of countries authorized, ~40% of sites initiated, aiming for mid-2025 enrollment.
• WHIM launch activities: conference attendance, peer-to-peer speaker program, patient-focused campaign with website, new materials, etc.
• Reimbursement and access good with over 150 million lives covered.

The company's main product is XOLREMDI (mavorixafor) approved for WHIM syndrome. Sales in Q2 had stocking with specialty pharma during initial launch. No detailed breakdown of absolute revenue and contribution % by product segments provided in the transcript.

Forward-Looking Statements

• Phase III trial of mavorixafor in CN expected to enroll in mid-2025.
• No specific sales guidance for XOLREMDI in 2025 provided yet, but commercial efforts ongoing for WHIM launch ramp-up.

Risks

• Risks associated with forward-looking statements regarding regulatory and product development, as detailed in X4's most recent SEC filings including Form 10-K and upcoming Form 10-Q.

Q: What were the biggest criteria for physicians to reduce G-CSF usage in the trial?

A: The important thing is the high and robust ANC responses due to the addition of mavorixafor, which gave physicians confidence in data, leading them to adjust G-CSF dosing.

Q: Early anecdotes on reduced pain or convenience benefits?

A: Early to assess, but broad reduction in G-CSF usage seen across 75% of patients, including some completely coming off G-CSF.

Q: Details on XOLREMDI patient initiative?

A: Launched a new patient-directed campaign with digital campaigns and hard copy material to educate patients and encourage them to discuss WHIM syndrome with their physician.

Q: Number of patients on XOLREMDI and commercialization setup?

A: Focus on disease awareness and screening, no specific patient count given yet, ramping up in 2025 with plans to provide more details later.

Q: Correlation between CN subtype and G-CSF dose reduction, and baseline G-CSF and dose reduction?

A: Phase II sample too small for subtype correlation; Phase III trial will analyze in detail the different subtypes and G-CSF profiles.

Q: Sales guidance for XOLREMDI 2025 and infection data in Phase II?

A: No sales guidance yet; Phase II not designed for infection rate assessment, but ANC correlates with infection risk based on G-CSF clinical trials and everyday use.