Pharming Group N.V. announced that the positive results of a Phase 3 clinical trial of the investigational drug leniolisib, an oral, selective phosphoinositide 3-kinase delta (PI3Kd) inhibitor, in adult and adolescent patients with activated phosphoinositide 3-kinase delta syndrome (APDS), a rare primary immunodeficiency, have been published in Blood,1 the peer-reviewed international medical journal of the American Society of Hematology. Data from this study was previously announced on February 2, 2022. The paper, entitled 'Randomized, Placebo-Controlled, Phase 3 Trial of PI3Kd Inhibitor Leniolisib for Activated PI3Kd Syndrome', outlined results from the multinational, triple-blind, placebo-controlled, randomized clinical trial, which enrolled 31 patients with APDS aged 12 years or older.

Patients were randomly assigned in a 2:1 ratio to receive 70 mg leniolisib or placebo twice daily for 12 weeks. Improvement over placebo was significant in the co-primary endpoints which evaluated reduction in lymph node size and increase in naïve B cells, reflecting the impact on immune dysregulation and correction of immunodeficiency in these patients, respectively. The adjusted mean change (95% CI) between leniolisib and placebo for lymph node size was -0.25 (-0.38, -0.12; P=0.0006; N=26) and for percentage of naïve B cells was 37.30 (24.06, 50.54; P=0.0002; N=13).

Leniolisib was well tolerated, and fewer patients receiving leniolisib reported study treatment-related adverse events (mostly grades 1-2) compared to those receiving placebo (23.8% vs 30.0%).