X4 Pharmaceuticals Announces Upcoming Presentation of Phase 2 Chronic Neutropenia Trial Data at the 30th Annual EHA Congress
X4 Pharmaceuticals (XFOR) announced the acceptance of two abstracts for poster presentation at the 30th Annual Congress of the European Hematology Association (EHA) in Milan. The presentations will showcase results from their completed Phase 2 trial of mavorixafor in treating primary chronic neutropenic (CN) disorders.
The six-month, open-label clinical trial enrolled 23 participants with idiopathic, congenital, or cyclic chronic neutropenia. Key findings include meaningful and durable increases in functional neutrophils with once-daily oral mavorixafor, and most physicians and participants opted to reduce G-CSF dosing when using mavorixafor in combination therapy. Mavorixafor represents the first innovation in CN treatment in over 30 years and could become the first oral treatment available if approved.
X4 Pharmaceuticals (XFOR) ha annunciato l'accettazione di due abstract per la presentazione poster al 30° Congresso Annuale della European Hematology Association (EHA) a Milano. Le presentazioni illustreranno i risultati del loro trial di Fase 2 completato sull'uso di mavorixafor nel trattamento dei disturbi cronici neutropenici (CN) primari.
Lo studio clinico open-label della durata di sei mesi ha arruolato 23 partecipanti affetti da neutropenia cronica idiopatica, congenita o ciclica. I risultati principali evidenziano aumenti significativi e duraturi dei neutrofili funzionali con l'assunzione orale giornaliera di mavorixafor; inoltre, la maggior parte dei medici e dei partecipanti ha scelto di ridurre il dosaggio di G-CSF quando mavorixafor veniva usato in terapia combinata. Mavorixafor rappresenta la prima innovazione nel trattamento della CN da oltre 30 anni e potrebbe diventare il primo trattamento orale disponibile se approvato.
X4 Pharmaceuticals (XFOR) anunció la aceptación de dos resúmenes para presentación en póster en el 30º Congreso Anual de la Asociación Europea de Hematología (EHA) en Milán. Las presentaciones mostrarán resultados de su ensayo de Fase 2 completado sobre mavorixafor en el tratamiento de trastornos crónicos neutropénicos (CN) primarios.
El ensayo clínico abierto de seis meses incluyó a 23 participantes con neutropenia crónica idiopática, congénita o cíclica. Los hallazgos clave incluyen aumentos significativos y duraderos en neutrófilos funcionales con mavorixafor oral una vez al día, y la mayoría de médicos y participantes optaron por reducir la dosis de G-CSF al usar mavorixafor en terapia combinada. Mavorixafor representa la primera innovación en el tratamiento de CN en más de 30 años y podría convertirse en el primer tratamiento oral disponible si se aprueba.
X4 Pharmaceuticals (XFOR)가 밀라노에서 열리는 제30회 유럽혈액학회(EHA) 연례 총회에서 포스터 발표를 위한 두 개의 초록이 채택되었음을 발표했습니다. 발표에서는 원발성 만성 호중구 감소증(CN) 치료를 위한 마보릭사포르의 2상 임상시험 완료 결과를 소개할 예정입니다.
6개월간 진행된 공개 라벨 임상시험에는 특발성, 선천성 또는 주기성 만성 호중구 감소증 환자 23명이 참여했습니다. 주요 결과로는 하루 한 번 경구 투여하는 마보릭사포르로 기능성 호중구가 의미 있고 지속적으로 증가했으며, 대부분의 의사와 참가자가 병용 요법 시 G-CSF 투여량을 줄이기로 선택했다는 점이 포함됩니다. 마보릭사포르는 30년 넘게 없었던 CN 치료 분야의 첫 혁신이며, 승인될 경우 최초의 경구 치료제가 될 수 있습니다.
X4 Pharmaceuticals (XFOR) a annoncé l'acceptation de deux résumés pour une présentation sous forme d'affiches lors du 30e Congrès annuel de l'European Hematology Association (EHA) à Milan. Les présentations mettront en avant les résultats de leur essai de phase 2 achevé sur le mavorixafor dans le traitement des troubles neutropéniques chroniques (CN) primaires.
L'essai clinique ouvert de six mois a recruté 23 participants atteints de neutropénie chronique idiopathique, congénitale ou cyclique. Les résultats clés montrent des augmentations significatives et durables des neutrophiles fonctionnels avec une administration orale quotidienne de mavorixafor, et la majorité des médecins et des participants ont choisi de réduire la dose de G-CSF lors de l'utilisation du mavorixafor en thérapie combinée. Le mavorixafor représente la première innovation dans le traitement de la CN depuis plus de 30 ans et pourrait devenir le premier traitement oral disponible s'il est approuvé.
X4 Pharmaceuticals (XFOR) gab die Annahme von zwei Abstracts für Posterpräsentationen auf dem 30. Jahreskongress der European Hematology Association (EHA) in Mailand bekannt. Die Präsentationen werden Ergebnisse ihrer abgeschlossenen Phase-2-Studie mit Mavorixafor zur Behandlung primärer chronischer Neutropenien (CN) vorstellen.
Die sechsmonatige, offene klinische Studie schloss 23 Teilnehmer mit idiopathischer, angeborener oder zyklischer chronischer Neutropenie ein. Wichtige Erkenntnisse sind bedeutende und anhaltende Steigerungen funktionaler Neutrophiler durch einmal täglich oral verabreichtes Mavorixafor, und die meisten Ärzte und Teilnehmer entschieden sich, die G-CSF-Dosis bei Kombinationstherapie mit Mavorixafor zu reduzieren. Mavorixafor stellt die erste Innovation in der CN-Behandlung seit über 30 Jahren dar und könnte, falls zugelassen, die erste orale Behandlung werden.
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Insights
X4's mavorixafor showed positive Phase 2 results in chronic neutropenia, supporting ongoing Phase 3 trial with potential first oral treatment in 30+ years.
The Phase 2 trial data for mavorixafor in chronic neutropenia (CN) disorders represents a significant potential advancement in treatment options. The study enrolled 23 participants with idiopathic, congenital, or cyclic chronic neutropenia and demonstrated meaningful and durable increases in functional neutrophils over the 6-month trial period. Most importantly, the majority of physicians and participants opted to significantly reduce G-CSF dosing when using mavorixafor in combination therapy.
This is particularly noteworthy as G-CSF (granulocyte colony-stimulating factor) has been the standard injectable treatment for chronic neutropenia for over three decades, with no oral alternatives available. G-CSF injections, while effective, can be burdensome for patients and associated with bone pain and other side effects. The ability to maintain target absolute neutrophil count (ANC) levels while reducing G-CSF dosage could substantially improve quality of life for CN patients.
The upcoming presentations at the EHA Congress will focus on two key aspects: the safety and efficacy of mavorixafor in raising ANC levels (both as monotherapy and in combination with G-CSF), and its potential to enable G-CSF dose reduction while maintaining clinically targeted neutrophil counts. These outcomes are clinically meaningful endpoints that directly address the therapeutic goals in CN management.
With the Phase 3 trial currently enrolling, these supportive Phase 2 results suggest mavorixafor could potentially become the first oral treatment approved for chronic neutropenia in more than 30 years, representing a significant innovation in this rare disease space.
Meaningful and durable increases in functional neutrophils observed over 6-month trial with oral once-daily mavorixafor
Majority of physicians and chronic neutropenia participants chose to significantly reduce G-CSF dosing when using mavorixafor in combination therapy
BOSTON, May 14, 2025 (GLOBE NEWSWIRE) -- X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced the acceptance of two abstracts for poster presentation at the 30th Annual Congress of the European Hematology Association (EHA) taking place in Milan, Italy from June 12-15, 2025. The abstracts published online today summarize the clinical results from the company’s completed Phase 2 trial of mavorixafor in the treatment of certain primary chronic neutropenic (CN) disorders.
“We are excited to present the positive data from our completed Phase 2 trial of chronic treatment of CN participants with mavorixafor to the global hematology community for the first time,” said Christophe Arbet-Engels, MD, PhD, Chief Medical Officer of X4 Pharmaceuticals. “With enrollment progressing in our ongoing pivotal Phase 3 trial in CN, we continue to look at these Phase 2 results as supportive of the design of the Phase 3 trial and a signal of its potential for success. Mavorixafor is the first innovation to be studied for the treatment of CN in more than 30 years and would be the first oral treatment available for this serious condition if approved.”
Summary of EHA Posters to be Presented:
The Phase 2 study of oral, once-daily mavorixafor was a six-month, open-label clinical trial that enrolled a total of 23 participants diagnosed with idiopathic, congenital, or cyclic chronic neutropenia. The two poster presentations at EHA will focus on clinical results based on the following goals of the study:
- Assessing safety and the ability of oral, once-daily mavorixafor to sustainably raise absolute neutrophil count (ANC) as a monotherapy and in combination with injectable granulocyte colony-stimulating factor (G-CSF); and
- Assessing whether treatment of participants with mavorixafor could enable the reduction of G-CSF dosage while maintaining clinically targeted ANC levels and physicians’ willingness to do so.
Evaluating the Safety and Efficacy of Mavorixafor, an Oral CXCR4 Antagonist, in Patients with Chronic Neutropenic Disorders: Results from the Phase 2 Study
Lead Author: Julia T. Warren, MD, PhD, Department of Pediatrics, Division of Hematology, Perelman School of Medicine, University of Pennsylvania, and Division of Pediatric Hematology, Children’s Hospital of Philadelphia
Poster #: PS1654
Poster Session: Bone marrow failure syndromes incl. PNH - Clinical
Date Available: Thursday, June 12
Mavorixafor, an Oral CXCR4 antagonist, Allows for Granulocyte-Colony Stimulating Factor Dose De-escalation in Patients with Chronic Idiopathic Neutropenia and Congenital Neutropenia
Lead Author: Julia T. Warren, MD, PhD, Department of Pediatrics, Division of Hematology, Perelman School of Medicine, University of Pennsylvania, and Division of Pediatric Hematology, Children’s Hospital of Philadelphia
Poster #: PS1669
Poster Session: Bone marrow failure syndromes incl. PNH - Clinical
Date Available: Thursday, June 12
About Chronic Neutropenia and Mavorixafor
Chronic neutropenia is a primary, rare blood condition lasting more than three months, persistently or intermittently, and characterized by low levels of circulating neutrophils, increased risk of infections, and reduced quality of life. Neutrophils are retained in the bone marrow by the CXCR4/CXCL12 axis, creating a reserve of cells. Downregulation of the CXCR4 receptor by mavorixafor, an orally active CXCR4 antagonist, has been shown to mobilize functional neutrophils from the bone marrow into the peripheral blood across multiple disease states. The level of circulating neutrophils is typically measured by drawing blood to determine the absolute neutrophil count (ANC).
About the Phase 1b/Phase 2 Chronic Neutropenia Trial
The Phase 1b/Phase 2 clinical trial (NCT04154488) was a proof-of-concept, open-label, multicenter study designed to assess oral mavorixafor, with or without injectable G-CSF, in participants with chronic neutropenic disorders, including idiopathic, cyclic, and congenital neutropenia. In the Phase 1b portion of the study (n=25), participants received one dose of oral mavorixafor and were assessed for magnitude of absolute neutrophil count (ANC) response and tolerability. The Phase 2 portion of the trial (n=23) assessed the safety, tolerability, and the impact on participants’ neutropenia of oral, once-daily mavorixafor with and without concurrent injectable G-CSF therapy over a six-month period in the same patient population.
About the 4WARD Global, Pivotal Phase 3 Clinical Trial
The 4WARD trial is a global, pivotal Phase 3 clinical trial (NCT06056297) evaluating the efficacy, safety, and tolerability of oral, once-daily mavorixafor (with or without G-CSF) in people with congenital, acquired primary autoimmune, or idiopathic chronic neutropenia who are experiencing recurrent and/or serious infections. The 52-week trial is a randomized, double-blind, placebo-controlled, multicenter study aiming to enroll 150 participants with confirmed trough ANC levels less than 1,000 cells per microliter at baseline screening and histories of two or more serious and/or recurrent infections in the prior year. The primary endpoint of the trial is based on two outcome measures: annualized infection rate and positive ANC response.
About X4 Pharmaceuticals
X4 is delivering progress for patients by developing and commercializing innovative therapies for those with rare diseases of the immune system and significant unmet needs. Leveraging expertise in CXCR4 and immune system biology, X4 has successfully developed mavorixafor, an orally available CXCR4 antagonist that is currently being marketed in the U.S. as XOLREMDI® in its first indication. The company is also evaluating additional uses of mavorixafor and is conducting a global, pivotal Phase 3 clinical trial (4WARD) in people with certain chronic neutropenic disorders. X4 is headquartered in Boston, Massachusetts. For more information, please visit www.x4pharma.com.
X4 Forward Looking Statements
This press release contains forward-looking statements within the meaning of applicable securities laws, including the Private Securities Litigation Reform Act of 1995, as amended. These statements may be identified by the words “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “target,” or other similar terms or expressions that concern X4’s expectations, strategy, plans, or intentions. Forward-looking statements include, without limitation, implied or express statements regarding the initiation, timing, progress, and results of our current and future preclinical studies and clinical trials.
Any forward-looking statements in this press release are based on management’s current expectations and beliefs. These forward-looking statements are neither promises nor guarantees of future performance, and are subject to a variety of risks and uncertainties, many of which are beyond X4’s control, which could cause actual results to differ materially from those contemplated in these forward-looking statements, including the risks that: trials, studies and research programs may be delayed and may not have satisfactory outcomes, additionally earlier trials and studies may not be predictive of later trials and studies, including assessing the ability of mavorixafor monotherapy to durably increase absolute neutrophil count in patients with chronic neutropenic; the design and rate of enrollment for current clinical trials may not enable successful completion of the trial(s); X4 may be unable to obtain and maintain regulatory approvals; adverse safety effects may arise from the testing or use of X4’s product and product candidates; and other risks and uncertainties, including those described in the section entitled “Risk Factors” in X4’s most recent Annual Report on X4’s Form 10-K, as well as in other filings X4 makes with the Securities and Exchange Commission, including its quarterly report on Form 10-Q, from time to time. X4 undertakes no obligation to update the information contained in this press release to reflect new events or circumstances, except as required by law.
| X4 Investor Contact: | X4 Media Contact: | |
| Daniel Ferry | Rhiannon Jeselonis | |
| LifeSci Advisors | Ten Bridge Communications | |
| daniel@lifesciadvisors.com | rhiannon@tenbridgecommunications.com | |
| (617) 430-7576 | ||
FAQ
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