Trial of Erythrocyte Encapsulated Thymidine Phosphorylase In Mitochondrial Neurogastrointestinal Encephalomyopathy

Who can take part

• Patients must be male or female, of any race, aged 18 years or older at Screening; Having IDMC reviewed the benefit risk profile and recommended progression to juvenile cohorts the age range will be extended to include patients:; aged 16 years or older after at least 24 patient months of exposure in patients aged 18 years or over; aged 12 years or older after at least 24 patient months of exposure in patients aged <18 years at the time of enrolment
• Patients must be diagnosed with MNGIE by demonstrating all of the following:; <18% normal thymidine phosphorylase activity in the buffy coat; >3 μmol/L plasma thymidine; >5 μmol/L plasma deoxyuridine; Confirmation of the presence of a pathogenic mutation in TYMP by sequencing
• Patients must be able to undergo study procedures
• Patients must agree to either remain completely true abstinent or to use 2 effective contraceptive methods from Screening until completion of the Follow up Visit
• Patients must be willing to sign and date the written informed consent form after the benefits and risks of taking part in this study have been explained to them, and to comply with the study restrictions

Who cannot take part

• Patients who have received a successful liver or bone marrow transplant
• Patients suitable for allogeneic haematopoietic stem cell transplantation (AHSCT)
• Patients who have donated blood in the 90 days prior to Screening
• Patients who have a significant history of alcoholism or drug/chemical abuse within 1 year prior to Screening, as determined by the Investigator
• Patients with a known history of human immunodeficiency virus, hepatitis B infection, or an active hepatitis C infection
• Patients who have an abnormality in heart rate, blood pressure, or body temperature at Screening that, in the opinion of the Investigator, increases the risk of participating in the study
• Patients who have, or have a history of, any clinically significant neurological, GI, renal, hepatic, cardiovascular, psychiatric, respiratory, metabolic, endocrine, haematological, or other major disorder (except for MNGIE, or disorders associated with MNGIE that, in the Investigator's opinion, do not constitute a risk when taking study drug and would not interfere with the study objectives) as determined by the Investigator
• Patients with any current malignancy, or a history of malignancy within 5 years prior to Screening, with the exception of adequately treated or excised non metastatic basal cell or squamous cell cancer of the skin or cervical carcinoma in situ
• Patients with any medical condition, which in the opinion of the Investigator, would make the patient unsuitable for enrolment or could interfere with the patient's participation in, or completion of, the study
• Patients with a confirmed red blood cell count of <3.0 × 10\^9 per mL
• Patients who meet any of the following criteria will not be eligible to participate in the study:
• Patients with a matched AHSCT donor
• Patients who are severely disabled (e.g., patient bed bound, incontinent, and unable to carry out any daily activities), or with a life expectancy of less than 12 months at Screening, based on the Investigator's judgment
• Female patients who are:; pregnant, planning a pregnancy, or are unwilling to use contraception; breastfeeding or lactating
• Patients who have an abnormality in the 12 lead electrocardiogram (ECG) at Screening that, in the opinion of the Investigator, increases the risk of participating in the study
• Patients who are currently enrolled in, or are planning to participate in, or discontinued within the last 30 days from a clinical study involving an investigational medicinal product or concurrently enrolled in medical research judged not to be scientifically or medically compatible with EE-TP