The U.S. Food and Drug Administration (FDA) has approved Xolremdi (mavorixafor), the first therapy to receive approval for the treatment of persons with WHIM syndrome.
WHIM syndrome is an acronym for a rare immunodeficiency disorder with each letter representing a predominant feature of the condition:
W = warts
H = hypogammaglobulinemia
I = infections
M = myelokathexis (retention of neutrophils in the bone marrow)
Symptoms usually begin in early childhood with recurrent bacterial infections such as respiratory infections and cellulitis. It is caused by genetic changes in the CXCR4 gene.
Mavorixafor
Mavorixafor is a selective CXC chemokine receptor 4 (CXCR4) antagonist. The drug works by targeting the underlying cause of disease and increasing the amount of mature circulating neutrophils and lymphocytes. The capsules are approved for patients ages 12 and older. Patients weighing more than 50 kg will receive 400 mg per day while those under 50 kg will receive 300 mg per day. The estimated annual cost for the capsules ranges from $373,300 (300 mg dose) to $496,400 (400 mg dose).
4WHIM Clinical Trial
The approval comes following results from the 4WHIM https://clinicaltrials.gov/study/NCT03995108, a phase 3 global, randomized, double-blind, placebo-controlled, 52-week multicenter study testing the safety and efficacy of mavorixafor in WHIM patients. Improvements were observed in absolute neutrophil counts, absolute lymphocyte counts, as well as a decrease in infections. Safety was also well observed with the most common adverse reaction being thrombocytopenia, pityriasis, rash, rhinitis, epistaxis, vomiting, and dizziness.
The approval of mavorixafor gives the manufacturers, X4 Pharmaceuticals, a Rare Pediatric Disease Priority Review voucher. The voucher can be used for subsequent drug applications that would not qualify for a priority review. A Priority Review designation means the FDA must review the drug application within 6 months instead of the standard 10 months. The voucher can also be sold to another company. Last year, Sarepta Therapeutics sold their voucher for $102 million.
For more information, visit https://investors.x4pharma.com/news-releases/news-release-details/x4-pharmaceuticals-announces-fda-approval-xolremditm-mavorixafor
To learn more about WHIM syndrome, visit our learning page at https://checkrare.com/learn-about-whim-syndrome/
