X4 Pharmaceuticals, Inc. · NASDAQ:XFOR

X4 Pharmaceuticals — Investor Presentation (September 2026)

20 slides from X4 Pharmaceuticals's investor presentation, Sep 9, 2026

  1. Slide 1: Corporate Presentation September 2026

    Corporate Presentation September 2026 Nasdaq: XFOR EXHIBIT 99.1

  2. Slide 2: Forward-Looking Statements

    Forward-Looking Statements 2 • This presentation, including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery of the presentation and any question and answer sessions and any documents or materials distributed at or in

  3. Slide 3: Delivering on the Promise of CXCR4 antagonist Mavorixafor

    Focused on improving the lives of people with rare hematology diseases Delivering on the Promise of CXCR4 antagonist Mavorixafor 1. WHIM (Warts, Hypogammaglobulinemia, Infections, Myelokathexis), a rare primary immunodeficiency and chronic neutropenic disorder. 3 • Mavorixafor (XOLREMDI®) approved f

  4. Slide 4: X4's Leadership Team – Turnaround, Drug Approval and Commercialization Experience

    Former CTI BioPharma Senior Management sold company to SOBI for $1.7B in 2023 X4’s Leadership Team – Turnaround, Drug Approval and Commercialization Experience 4 cDavid Kirske Chief Financial Officer cAdam Craig, MD PHD Executive Chair cJohn Volpone President and COO

  5. Slide 5: Mavorixafor: An oral agent designed to alleviate neutropenia

    Validated mechanism with the potential to increase neutrophil counts and decrease infection rates Mavorixafor: An oral agent designed to alleviate neutropenia 1. Bainton DF (1980) The Cell Biology of Inflammation, vol 2, pp 1–25. Amsterdam: Elsevier/North-Holland. 2. Furze RC, et al, Immunology. 200

  6. Slide 6: Chronic Neutropenia – Increasing Risk of Serious Infections and Hospitalization

    Chronic Neutropenia (CN) – Increasing Risk of Serious Infections and Hospitalization 1. https://ctep.cancer.gov/protocoldevelopment/electronic_applications/docs/ctcae_v5_quick_reference_8.5x11.pdf. 2. Palmblad J, Dufour C, Papadaki HA. Haematologica. 2014 Jul;99(7):1130-1133. 3. Sicre de Fontbrune F

  7. Slide 7: Chronic Neutropenia Opportunity – High unmet need in ~15K patients in U.S.

    Large number of primary CN patients experiencing severe/life threatening and recurrent infections Chronic Neutropenia Opportunity – High unmet need in ~15K patients in U.S. 1. Analysis of claims data derived from Veeva Compass 2+ claims with ICD-10 codes: D70.0, D70.4, D70.8, D70.9 between January 2

  8. Slide 8: Significant Opportunity to Address Unmet Needs in CN Community

    Broad opportunity for mavorixafor use as monotherapy or in combination with G-CSF Significant Opportunity to Address Unmet Needs in CN Community 1. X4 Market Research, July 2023 – data on file; ICD-10 Code Research (2017-2023). 2. G-CSF – Granulocyte Colony Stimulating Factor. 8 Current use of G-CSF

  9. Slide 9: Unmet Needs For CN Patients

    13 20 22 22 25 26 30 32 32 34 35 Intravenous treatment options Alternative mechanisms of action to G-CSF Safer treatment options Decrease in acute antimicrobial dose / freq. Decrease in G-CSF dose / frequency Lower frequency of infections Decrease in proph. antimicrobial dose / freq. Decreased sever

  10. Slide 10: Phase 2 Proof of Concept Study of Mavorixafor in Chronic Neutropenia

    10 Phase 2 Proof of Concept Study of Mavorixafor in Chronic Neutropenia Phase 2 Study N=23 patients Baseline Assessed Safety and Durability of ANC Levels over 6-Month Period Once-Daily Oral Mavorixafor: Monotherapy +/-G-CSF DAY -1 Month 1 Month 3 Month 6 Study Visits Assessments at Baseline, Month 1

  11. Slide 11: Phase 2 Clinical Study in Chronic Neutropenia: Participant Disposition

    Study group representative of typical CN population with history of prior infections Phase 2 Clinical Study in Chronic Neutropenia: Participant Disposition 1. Congenital CN participants included those with ELANE variant (n=2), VPS13B variant (Cohen syndrome), G6PC3 variant/ deficiency, SRP54 variant

  12. Slide 12: Mavorixafor Monotherapy Increased Mean ANC

    Mavorixafor Monotherapy Increased Mean ANC 1. Data set contains two LOCF (last observation carried forward) values: one value missing at M3 assessment, one value missing at M6. 2. One patient discontinued prior to Month 3 assessment (no change from data set presented on 6/27/2024). 3. One patient di

  13. Slide 13: Substantial Reductions in G-CSF on Study

    13 Substantial Reductions in G-CSF on Study G-CSF: • Treating physicians chose to reduce injectable G-CSF therapy in 9 of 12 (75%) eligible patients • Three patients with dose adjustments had G-CSF usage stopped by 6 months • Mean ANC maintained at normal levels (>1,500 cells/µL) through Month 6 • D

  14. Slide 14: Mavorixafor maintains normal ANC counts with G-CSF stoppages and dose reductions

    Mavorixafor maintains normal ANC counts with G-CSF stoppages and dose reductions 14 Data demonstrates the potential to reduce or stop G-CSF usage with mavorixafor no neutropenia mild neutropenia moderate neutropenia severe neutropenia Month 3 (n=12) Month 6 (n=12) Month 1 (n=12) Baseline (n=13) 4034

  15. Slide 15: Phase 2 Chronic Neutropenia Study Safety Summary

    Mavorixafor is well tolerated as both monotherapy and in combination with G-CSF Phase 2 Chronic Neutropenia Study Safety Summary 1. TEAE: treatment-emergent adverse event. 15 Combination (n=13), n (%) Monotherapy (n=10) n (%) Overall (n=23) n (%) Any Related AE 10 (76.9) 7 (70.0) 17 (73.9) Nausea 4

  16. Slide 16: Pivotal Phase 3 4WARD Study in Chronic Neutropenia

    Full enrollment expected Q4 2026 with top-line data expected H1 2028 Pivotal Phase 3 4WARD Study in Chronic Neutropenia 16 Mavorixafor (50%) +/- G-CSF Placebo (50%) +/- G-CSF Global, Double-Blind, Placebo-Controlled Trial Screening Baseline Visit and 1:1 Randomization N=126 ANC assessments at baseli

  17. Slide 17: Cash Runway Expected into 2029

    Cash Runway Expected into 2029 Financial Position 17 Fully diluted common stock outstanding includes pre-funded warrants June 30, 2026 Cash Fully Diluted Common Stock Outstanding $208 M 145.6 M

  18. Slide 18: X4 on Track to Deliver Pivotal Phase 3 Data in H1 2028

    Potential FDA approval late 2028/early 2029 X4 on Track to Deliver Pivotal Phase 3 Data in H1 2028 18 • Large market opportunity for mavorixafor in CN in the US • ~15,000 patients with moderate and severe disease • Clear medical need for well tolerated oral agent - monotherapy or in combination with

  19. Slide 19: Appendix

    PHARMACEUTICALS : Appendix

  20. Slide 20: Mavorixafor: Pipeline and Partners

    20 Mavorixafor: Pipeline and Partners Indication Pre-clinical Phase 1 Phase 2 Phase 3 Approved Partners Expected Milestones M av or ix af or Chronic Neutropenia (Congenital, Autoimmune, Idiopathic) Full enrollment Q4 2026 Top-line data H1 2028 WHIM Syndrome (Warts, Hypogammaglobulinemia, Infections,

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