Gene Transfer Study in Patients With Late Onset Pompe Disease

Open to people ages 18-80

• Subject is aged ≥ 18 years.
• Subject has a documented clinical diagnosis of Pompe disease by genetic testing.
• Subject has received enzyme replacement therapy (ERT) with rhGAA for the previous ≥ 2 years.
• Subject has been on a stable standard dose (at least 20 mg/kg every 2 weeks) of ERT with rhGAA for at least the previous 6 months.
• Subject or legally authorized representative(s) (LAR) (if applicable) provides written informed consent.
• Subject and LAR(s) are willing and able to comply with study visits and study procedures.
• Subject must agree to refrain from blood or blood products donation and sperm or egg donation from the time of AT845 administration until the later of 90 days or 3 consecutive negative viral shedding samples
• Subjects enrolled in previous protocol versions 1 through 9: Subject has upright FVC ≥ 30% of predicted normal value. Subjects enrolled in protocol version 10: Subject has upright FVC ≥ 30% and ≤ 85% of predicted normal value.
• Subjects enrolled in protocol version 10: Subject who is able to ambulate ≥ 40 m without stopping and without the use of an assistive device. The use of an assistive device for community ambulation is acceptable. (Subjects enrolled under previous protocol versions 1 through 9 will not be excluded if they do not meet this criterion during re-screening visit).

• Subject is currently participating in an interventional study or has received gene or cell therapy.
• Subject tests positive for AAV8 antibodies with titers >1:20 neutralizing.
• Subject has received immune-modulating agents within 90 days before dosing (use of inhaled corticosteroids is allowed); use of other concomitant medications to manage chronic conditions must have been stable for at least 30 days before dosing. Concomitant medications that may predispose the subject to peripheral neuropathy will be evaluated.
• Subject has any clinically significant laboratory values (other than those directly associated with LOPD [e.g., GAA, serum creatine kinase (CK)]) that would preclude participation in the study.
• Subject has clinically significant underlying liver disease at Screening, or has any of the following:
• Gamma glutamyl transferase (GGT) > 5.0 x upper limit of normal (ULN)
• Active hepatitis B or C, and hepatitis B surface antigen (HBsAg), HB core antibody (HBcAb), HBV-DNA positivity or HCV-RNA viral load positivity, respectively.
• Negative viral load assays in 2 samples, collected at least 6 months apart, will be required to be considered negative. Both natural clearers and those who have cleared HCV on antiviral therapy are eligible.
• Currently on antiviral therapy for hepatitis B or C
• Subject has serological or viral load evidence of HIV-1 or HIV-2.
• Subject has received drugs for treatment of myopathy or neuropathy with immunosuppressive therapy (e.g., corticosteroids, cyclosporine, tacrolimus, methotrexate, cyclophosphamide, IV immunoglobulin, rituximab) within 3 months prior to starting the study
• Subject has a high risk for a severe allergic reaction to rhGAA (ie, previous moderate to severe anaphylactic reaction to alglucosidase alfa or and/or a history of sustained high immunoglobulin G [IgG] antibody titers to alglucosidase alfa that suggests a high risk for an allergic reaction to ERT).
• Subject has a history of hypersensitivity to β2 agonist drugs such as albuterol, levalbuterol, bitolterol, pirbuterol, terbutaline, salmeterol, which contraindicates pulmonary function testing.
• Subject has an active viral infection based on clinical observation.
• Subject has a history of or concurrent medical condition other than Pompe disease that could jeopardize safety of the subject or impact study results.
• Subject has a history of, or currently has, a clinically important cardiac condition, such as an echocardiogram (ECHO) with ejection fraction below 40% or has symptoms or signs of cardiomyopathy that precludes enrollment.
• Subject has a contraindication to study drug or to corticosteroids, or has demonstrated hypersensitivity to any of the components of the study drug.
• Subject tests positive for GAA antibodies with titers > 1:50,000 total
• Subject has a history of hypersensitivity to MRI contrast agents including gadolinium.
• Subject has a known hypersensitivity to local anesthetics such as lidocaine.
• Subject has a bleeding diathesis, e.g., due to anti-coagulation or anti-platelet treatments.
• Subject has a concurrent medical condition (including uncontrolled diabetes, alcohol use disorder, certain autoimmune conditions, Lyme disease, active malignancy requiring chemotherapy and/or radiation, uremic nephropathy, known exposure to heavy metals) commonly associated with peripheral neuropathy. Other concurrent medical conditions that may predispose to peripheral neuropathy will be evaluated and action taken on a case-by-case basis, following discussion between the Investigator and Medical Monitor.
• Subject who is unwilling to withdraw from ERT.
• Subject has an active symptomatic large fiber peripheral neuropathy diagnosed by a neurologist at a screening visit.
• Age-related sensory changes on NCS without symptoms or mononeuropathy (refers to focal involvement of a single nerve, usually due to a local cause such as trauma, compression or entrapment) will not be excluded.