Three Poster Presentations Demonstrate The Long-Term Efficacy of Mavorixafor in Primary Immunodeficiencies

X4 Pharmaceuticals Inc. has recently published data from 3 different posters which were presented at the American Society of Hematology (ASH) Annual Meeting in Georgia. You can read the full posters on their website here, but below is a brief summary of each.

Poster 1

The first poster (#2186) highlighted how Mavorixafor, a CXCR4, when administered orally, is able to increase the peripheral white blood cell count. This was found to be true across many different conditions, including chronic neutropenia, Waldenström’s macroglobulinemia (WM), WHIM (Warts, Hypogammaglobulinemia, Infections, Myelokathexis) syndrome, clear cell renal cell carcinoma (ccRCC), and chronic idiopathic neutropenia (CN).
The medication was found to increase monocytes, lymphocytes, and neutrophils. Additionally, it was efficacious both in the short term as well as in the long term.
Mavorixafor remained efficacious when used in addition to ibrutinib, glanulocyte-colony stimulating factor (G-CSF), and axitinib.
The results ultimately demonstrated that mavorixafor may be able to minimize the severity of many different immunodeficiencies. It may have a much broader potential than previously realized. Additionally, it has potential regardless of whether or not CXCR4 mutations are present.

Poster 2

The second poster (#1121) focused on mavorixafor as a therapy for those diagnosed with WHIM syndrome. It shared the findings from the extension portion of an open-label Phase 2 trial. The median duration of treatment was 148.4 weeks.

The therapy was found to be well tolerated over the long term. Additionally, there were durable raises in monocytes, lymphocytes, and neutrophils. Improvements in warts and in infections were sustained.

Further, the higher the dose of the treatment, the lower infection rates dropped.

Patient interviews were also conducted which demonstrated the treatment was tolerated well, hospital trips decreased, and infection prevalence and duration decreased.

There is now a Phase 3 trial for WHIM syndrome which is ongoing. The primary endpoint of this trial is time above threshold for ANC. Results from this Phase 3 trial are anticipated by the last quarter of 2022. The trial will last a total of 52 weeks.

So far, this therapy remains to look like a safe, tolerable, effective therapy for WHIM syndrome.

Poster 3

The 3rd poster (#2063) examined functional analyses of different CXCR4 WHIM syndrome mutations.

The researchers found that AKT activation as well as CXCR4 internalization may be key assays to predict pathogenicity of CXCR4 variants in vitro. Additionally, all of the CXCR4 cell line variants examined were found to be sensitive to the therapy.

You can read more about these posters and findings surrounding CXCR4 here.

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