Pharming Group NV (EURONEXT Amsterdam: PHARM) (Nasdaq: PHAR), a Netherlands-based global biopharmaceutical company, announced on Wednesday that it has enrolled its first patient in its Phase III clinical trial in Japan, assessing leniolisib for the treatment of activated phosphoinositide 3-kinase delta syndrome (APDS) in adult and paediatric patients 12 years of age and older.

APDS is a rare primary immunodeficiency that was first characterised in 2013. It is characterised by a variety of symptoms, including severe, recurrent sinopulmonary infections, lymphoproliferation, autoimmunity, and enteropathy.

The company's single-arm, open-label clinical trial is intended to assess the safety, tolerability, and efficacy of leniolisib in three patients 12 years of age and older who have a confirmed APDS diagnosis. Each patient is to receive weight-based dosing up to 70mg of leniolisib twice daily for 12 weeks. The primary efficacy endpoints and secondary endpoints of the study mirror those used to assess the clinical results in each of the leniolisib APDS trials.

The firm is planning to include data from the trial in a future registration application for the approval of leniolisib to be filed with Japan's Pharmaceuticals and Medical Devices Agency (PMDA). Eligible subjects enrolled in the trial are to continue to receive the investigational drug for around one year through an open-label extension trial.

Hirokazu Kanegane, professor of the Department of Child Health and Development, Tokyo Medical and Dental University, said: "The initiation of this clinical study is a positive step for the APDS community in Japan. With patients currently reliant on supportive treatments, the prospect of a disease-modifying treatment for this rare primary immunodeficiency could represent an exciting new treatment option for patients, their families, caregivers and their doctors in Japan."