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Clinical Trials

X4P-001-RD demonstrates promising activity in WHIM syndrome patients

PBR Staff Writer Published 18 June 2018

X4 Pharmaceuticals said that its X4P-001-RD has demonstrated promising activity in the ongoing open-label phase 2 portion of a phase 2/3 study in patients with WHIM syndrome.

WHIM syndrome is a primary immunodeficiency disease caused by a mutation in the C-X-C receptor type 4 (CXCR4) gene, which results in susceptibility to certain types of infections.

The X4P-001-RD is an oral and small molecule inhibitor of CXCR4 being developed for use as a life-long treatment for patients with WHIM syndrome and other primary genetic immunodeficiencies.

At present, the X4P-001-RD is being assessed in a phase 2/3 trial in patients with WHIM syndrome.

The interim results from the phase 2 portion of the trial showed promising activity of X4P-001-RD with dose-dependent increases in absolute neutrophil and lymphocyte counts in patients with WHIM syndrome.

The study showed that majority of patients had improved levels of neutrophil and lymphocyte counts with daily oral administration of X4P-001-RD.

According to the company, measurement of circulating neutrophils and lymphocytes are endpoints in the X4P-001-RD clinical study, as leukocytes are retained in the patient’s bone marrow in WHIM syndrome patients.

The study lead investigator David Dale said: “In this study, X4P-001-RD showed consistent increases in neutrophils and lymphocytes, the primary biomarker for response to therapy.

“Increases in these biomarkers are an indication of an improvement in the pathophysiology underlying WHIM syndrome. One exciting example of improvement was a reduction in HPV-related warts following X4P-001-RD therapy in one patient.”

In the phase 3 portion of the trial, all patients showed a dose-dependent increase in neutrophils and lymphocytes from screening values.

The X4P-001-RD drug exposure demonstrated a dose-dependent increase that correlated with increases in absolute neutrophil count.

The X4P-001-RD was noticed to be well tolerated for durations up to 400 days and to doses including 400 mg daily without serious adverse events.

X4 Pharmaceuticals chief medical officer Sudha Parasuraman said: “Our clinical program with X4P-001-RD in WHIM syndrome has made significant progress, with the establishment of the recommended dose for our future Phase 3 study in WHIM syndrome.”