Safety and pharmacokinetics of Alpha-1 MP (Prolastin®-C) in Japanese patients with alpha1-antitrypsin (AAT) deficiency

Abstract

Background: Alpha₁-Proteinase Inhibitor, Modified Process (Alpha-1 MP) is used for augmentation therapy in alpha1-antitrypsin deficiency (AATD), an extremely rare disease in Japan. Weekly doses of 60 mg/kg Alpha-1 MP have been shown to be safe and well tolerated in non-Japanese subjects, but the safety and pharmacokinetics (PK) have not been evaluated in Japanese subjects. The objectives of this study were to evaluate the safety and PK of 60 mg/kg Alpha-1 MP administered by weekly IV infusions over 8 weeks in Japanese subjects with AATD.

Methods: This was a multicenter, open-label trial in Japanese adults aged ≥20 years with AATD. Samples for evaluation of serum alpha₁-PI concentration and PK parameters were collected at 10 time points until the seventh day after the last dose at Week 8: immediately before dosing, immediately after dosing (time 0), and 0.25, 2, 4, 8, 24, 48, 120, and 168 hours after dosing.

Results: Four subjects were analyzed. The median t_max was 0.534 h. Mean ± SD values for t_½, C_max, and AUC_0-7days were 150.4 ± 36.18 h, 174.2 ± 30.51 mg/dL, and 14,913.2 ± 1633.45 mg*h/dL, respectively. Mean trough concentration at week 8 was 55.4 ± 7.23 mg/dL. Alpha-1 MP therapy was safe, with no serious adverse events or deaths reported. Two treatment-emergent adverse events of fatigue in one subject were considered to be possibly related.

Conclusions: The PK and safety of Alpha-1 MP in Japanese subjects with AATD were consistent with the Alpha-1 MP profile in non-Japanese subjects (ClinicalTrials.gov: NCT02870309; JAPIC CTI: JapicCTI-163160).

Keywords: AAT deficiency; Alpha(1)-proteinase inhibitor; Japanese; Pharmacokinetics; Safety.