BOSTON, Mass. — X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced that the U.S. Food and Drug Administration (FDA) has approved XOLREMDI™ (mavorixafor) capsules for use in patients 12 years of age and older with WHIM syndrome (warts, hypogammaglobulinemia, infections and myelokathexis) to increase the number of circulating mature neutrophils and lymphocytes.
XOLREMDI, a selective CXC chemokine receptor 4 (CXCR4) antagonist, is the first therapy specifically indicated in patients with WHIM syndrome, a rare, combined primary immunodeficiency and chronic neutropenic disorder caused by CXCR4 pathway dysfunction. People with WHIM syndrome characteristically have low blood levels of neutrophils (neutropenia) and lymphocytes (lymphopenia) and experience serious and/or frequent infections. The FDA granted Breakthrough Therapy Designation to mavorixafor in WHIM syndrome and evaluated the New Drug Application (NDA) under Priority Review, a designation for therapies that have the potential to provide significant improvement in the treatment, diagnosis, or prevention of serious conditions.
“The approval of XOLREMDI is a transformational milestone both for X4 and, more importantly, for the WHIM syndrome community,” said Paula Ragan, Ph.D., President and Chief Executive Officer of X4 Pharmaceuticals. “We are incredibly grateful to the people living with WHIM syndrome, their families, and the investigators who took part in our clinical program, to U.S. regulators for their continued focus on rare-disease treatment development, and to our dedicated employees for making this targeted breakthrough therapy a reality.”
“Effective and innovative treatments are critical for those diagnosed with a primary immunodeficiency. The approval of XOLREMDI marks an important advancement for people living with WHIM syndrome, who are susceptible to serious and frequent infections,” said Jorey Berry, President and Chief Executive Officer of the Immune Deficiency Foundation (IDF). “We are very pleased to have been a partner to X4 in their journey to bring this much-needed treatment to this underserved rare disease community.”
Teresa K. Tarrant, M.D., Associate Professor of Medicine, Rheumatology, and Immunology at Duke University School of Medicine and a principal investigator in the 4WHIM trial, commented on the news: “Until now, supportive care for people with WHIM syndrome has focused on symptom management and not the underlying cause of disease — the dysfunction of the CXCR4 pathway. I am thrilled that with the approval of XOLREMDI, a therapy designed to address dysregulated CXCR4 pathway signaling, we now have a targeted treatment that has demonstrated the ability to elevate absolute neutrophil and lymphocyte counts, increasing WHIM patients’ ability to fight infections.”
The FDA approval of XOLREMDI was based on results of the pivotal, 4WHIM Phase 3 clinical trial, a global, randomized, double-blind, placebo-controlled, 52-week multicenter study that evaluated the efficacy and safety of XOLREMDI in 31 people aged 12 years and older diagnosed with WHIM syndrome. The efficacy of XOLREMDI was determined by improvement in absolute neutrophil counts (ANC), improvement in absolute lymphocyte counts (ALC), and a reduction in infections. In the 4WHIM trial, XOLREMDI treatment demonstrated increased time above threshold (≥500 cells/microliter) for absolute neutrophil count (TAT-ANC) vs. placebo (p<0.0001) and increased time above threshold (≥1000 cells/microliter) for absolute lymphocyte count (TAT-ALC) v. placebo (p<0.0001). The efficacy of XOLREMDI was further assessed in a composite endpoint consisting of total infection score and total wart change score using a Win-Ratio method. Analyses of the individual components of this composite endpoint showed an approximate 40% reduction in total infection score, weighted by infection severity, in XOLREMDI-treated patients compared with placebo-treated patients. There was no difference in total wart change scores between the XOLREMDI and placebo treatment arms over the 52-week period. Treatment with XOLREMDI also resulted in a 60% reduction in the annualized infection rate compared with placebo-treated patients. The most common adverse reactions reported in the 4WHIM trial (≥10% and more frequently reported than placebo) were: thrombocytopenia, pityriasis, rash, rhinitis, epistaxis, vomiting, and dizziness.
With the FDA approval of XOLREMDI, X4 has received a Rare Pediatric Disease Priority Review Voucher that can be used to obtain priority review for a subsequent application or sold to another drug sponsor.
X4Connect™ Offers Disease and Treatment-Related Support
X4 is committed to helping people with WHIM syndrome access XOLREMDI and announced today the launch of X4Connect, offering eligible U.S. patients dedicated support throughout their XOLREMDI treatment journey, including disease and treatment-related resources, help navigating insurance coverage, and copay assistance. For additional information about X4Connect, call 1-844-X4CNNCT (844-942-6628), Monday-Friday, 8am-8pm ET or visit https://www.xolremdihcp.com/access-and-support.
XOLREMDI will be commercially available in the U.S. through X4’s specialty pharmacy partner PANTHERx® Rare.
IMPORTANT SAFETY INFORMATION
CONTRAINDICATION
XOLREMDI is contraindicated with drugs highly dependent on CYP2D6 for clearance.
WARNINGS AND PRECAUTIONS
Embryo-Fetal Toxicity: Based on its mechanism of action, XOLREMDI is expected to cause fetal harm. Verify pregnancy status of female patients of reproductive potential prior to starting XOLREMDI. Advise females of reproductive potential to use effective contraception during treatment with XOLREMDI and for three weeks after the final dose.
QTc Interval Prolongation: XOLREMDI causes concentration-dependent QTc prolongation. Correct any modifiable risk factors for QTc prolongation, assess QTc at baseline, and monitor QTc during treatment as clinically indicated in patients with risk factors for QTc prolongation or receiving concomitant medications that increase XOLREMDI exposure and/or drugs with a known potential to prolong the QTc interval. Dose reduction or discontinuation of XOLREMDI may be required.
ADVERSE REACTIONS
The most common adverse reactions (in ≥10% patients and more frequently reported than placebo) were thrombocytopenia, pityriasis, rash, rhinitis, epistaxis, vomiting, and dizziness.
DRUG-DRUG INTERACTIONS
Avoid co-administration of XOLREMDI and strong CYP3A4 inducers. Reduce XOLREMDI daily dosage when administered with strong CYP3A4 inhibitors. Monitor more frequently for adverse reactions associated with an increase in exposure of XOLREMDI when used concomitantly with moderate CYP3A4 inhibitors or P-gp inhibitors and reduce XOLREMDI daily dosage if necessary.
USE IN SPECIFIC POPULATIONS
Advise females that breastfeeding is not recommended during treatment with XOLREMDI and for three weeks after the final dose.
The safety and effectiveness of XOLREMDI have not been established in pediatric patients younger than 12 years of age.
XOLREMDI is not recommended in patients with severe renal impairment, end-stage renal disease, or moderate to severe hepatic impairment.
To report suspected adverse reactions, contact X4 Pharmaceuticals at 1-866-MED-X4MI (1-866-633-9464) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Please see the full Prescribing Information for XOLREMDI.
About WHIM Syndrome
WHIM syndrome is a rare, combined primary immunodeficiency and chronic neutropenic disorder caused by CXCR4 receptor dysfunction that results in impaired mobilization of white blood cells from the bone marrow into peripheral circulation. WHIM syndrome is named for its four classic manifestations: warts, hypogammaglobulinemia, infections, and myelokathexis, although only a minority of patients experience all four manifestations in the acronym. People with WHIM syndrome characteristically have low blood levels of neutrophils (neutropenia) and lymphocytes (lymphopenia), and as a result, experience serious and/or frequent infections. It is estimated that at least 1,000 people are currently diagnosed with WHIM syndrome in the U.S.
About XOLREMDI™ (mavorixafor)
XOLREMDI (mavorixafor) is a selective CXCR4 receptor antagonist approved in the U.S. for use in patients 12 years of age and older with WHIM syndrome to increase the number of circulating mature neutrophils and lymphocytes. CXCR4 receptor stimulation by its ligand, CXCL12, has been shown to play a key role in the movement of white blood cells (leukocytes) to and from the bone marrow compartment. Treatment with XOLREMDI results in increased mobilization of neutrophils and lymphocytes from the bone marrow into peripheral circulation.
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 our expertise in CXCR4 and immune system biology, we have successfully developed mavorixafor, which has received U.S. approval as XOLREMDI™ (mavorixafor) capsules in its first indication. We are also evaluating the use of mavorixafor in additional potential indications. X4 corporate headquarters are in Boston, Massachusetts and our research center of excellence is in Vienna, Austria.
Investor Contact
Daniel Ferry
Managing Director, LifeSci Advisors
[email protected]
(617) 430-7576
Media Contact
Kit Rodophele
Account Director, Ten Bridge Communications
[email protected]