Additional details surrounding the development strategy for AT2220 in combination with ERT for Pompe disease will be provided during a live presentation and webcast at the 31 st Annual JPMorgan Healthcare Conference on January 9, 2013 at 3:00 p.m. PT.
Study 010 Results – AT2220 Co-Administered with ERT (n=23)
Study 010 investigated single ascending oral doses of AT2220 co-administered with Myozyme or Lumizyme in patients with Pompe disease. The doses of AT2220 were 50 mg (Cohort 1), 100 mg (Cohort 2), 250 mg (Cohort 3), and 600 mg (Cohort 4). Each patient received one infusion of ERT alone, and then a single oral dose of AT2220 one hour before the next ERT infusion. Highlights from all four dose cohorts of AT2220 were as follows:
Single doses of AT2220 co-administered with ERT were well-tolerated, with no drug-related adverse events reported. In addition, AT2220 was cleared from muscle to near-undetectable levels by Day 7 in all four cohorts.
Recombinant Human GAA (rhGAA) Enzyme Activity in Plasma:
24-hour plasma PK was measured during and after each infusion. Plasma rhGAA activity increased in 23 out of 23 patients (100%) following co-administration and the increases were dose-related. These data suggest that co-administration increases the amount of stabilized, properly folded, and active rhGAA enzyme available for uptake into tissue.
Enzyme Activity in Muscle:
Muscle biopsies were taken to measure GAA enzyme uptake into muscle tissue, with and without AT2220. In Cohort 1, all 4 patients had muscle biopsies on Day 7. In Cohorts 2-4, muscle biopsies were taken on Day 3 for half the patients, and on Day 7 for the other half of patients.
In Cohort 1, no consistent change in GAA enzyme activity was observed at day 7. In Cohorts 2, 3, and 4 the results show that more enzyme is taken up into muscle tissue following AT2220 co-administration compared to ERT alone. The effect was most pronounced at the highest (600 mg) dose of AT2220.
At Day 3 the GAA enzyme activity in muscle following co-administration compared to ERT alone in patients with evaluable biopsies increased by the following: 25% in Cohort 2 (n=3), 7% in Cohort 3 (n=3), and 133% in Cohort 4 (n=2). At Day 7 the GAA enzyme activity in muscle was lower relative to Day 3, as expected based on the cellular half-life of the enzyme. However, following co-administration compared to ERT alone in patients with evaluable biopsies the following increases were sustained: 20% in Cohort 2 (n=3), 40% in Cohort 3 (n=2), and 20% in Cohort 4 (n=3).