Biopharmaceutical company Pharming Group N.V. (Euronext Amsterdam:PHARM) (NASDAQ:PHAR) on Tuesday announced positive topline Phase II data for leniolisib in genetically identifiable primary immunodeficiencies (PIDs) with immune dysregulation linked to PI3K delta signalling, with the findings accepted as a late-breaking abstract at ESID 2026.

The single-arm, open-label study evaluated safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy in 13 patients with genetically defined PIDs.

Leniolisib was generally well tolerated, with clinical improvements across measures of immune dysregulation, including a mean 26.4% reduction in spleen volume and reductions in the size of index lesions. Safety findings were consistent with the known profile of leniolisib, with infections the most common events and no new safety signals identified.

Nine of the 13 patients also had common variable immunodeficiency (CVID). Pharming expects to report Phase II results in CVID patients with immune dysregulation in the fourth quarter of 2026.

Additional data from the study will be presented at the 22nd Biennial Meeting of the European Society for Immunodeficiencies (ESID) in the Netherlands in October.

Leniolisib is an oral PI3K delta inhibitor approved for activated PI3K delta syndrome in multiple markets. Its safety and efficacy in PIDs with immune dysregulation beyond activated phosphoinositide 3-kinase delta (PI3K delta) syndrome (APDS) have not been established.