A Study of BMN 255 in Participants With Non-Alcoholic Fatty Liver Disease And Hyperoxaluria

Inclusion Criteria:

1. History of NAFLD with a liver fat content ≥ 8.0%, as determined by Fibroscan (transient elastography) or magnetic resonance imaging-derived proton density fatfraction (MRI-PDFF) during screening.

2. Hyperoxaluria, as defined by 24-hour urine oxalate excretion ≥ 45 mg/24 hours/1.73m2at 2 independent assessments during screening. The pre-dose 24-hour urine oxalatemeasure at Day 1 will be used for baseline but will not be required for inclusion inthe study

3. History of kidney stones (at least 1 stone prior to screening based on medicalhistory); participants with a known personal or family history of cystinuria orcystine kidney stones, calcium phosphate stones, struvite stones, or urate stonesshould not be included.

4. Contraceptive use by men and women use throughout the study period

5. Participants must be capable of giving signed informed consent

Exclusion Criteria:

1. Clinical history (including family history) or genetic analyses consistent withprimary hyperoxaluria (Type 1, 2, or 3).

2. History or current evidence of inflammatory bowel disease (including, but notlimited to: Crohn's disease, ulcerative colitis, celiac disease / gluten-sensitiveenteropathy) or evidence of chronic fat malabsorption (steatorrhea) due to any cause (eg, pancreatic insufficiency).

3. Significant history or clinical manifestation of any other allergic, dermatological,hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal,neurological, respiratory, endocrine, or psychiatric disorder, as determined by theinvestigator. Participants with Type II diabetes will be permitted to enroll butmust meet the concomitant therapy requirements listed below.

4. Use or intend to use any prescription medications/products within 14 days prior toPeriod 1 check-in, other than permitted oral medications to treat controlledhypertension, dyslipidemia and/or to lower triglycerides, and oralanti-hyperglycemic agents (AHAs), including, but not limited to, metformin,sulfonylureas, and dipeptidyl peptidase IV (DPP-IV) inhibitors, if approved by theinvestigator. Participants who require insulin injections, glucagon-like peptide-1agonists, pioglitazone, or vitamin E ≥ 800 mg should not be included in the study. Note: Participants receiving lipid-modifying therapies and participants withcontrolled hypertension and/or diabetes must have been on a stable treatment regimen (medication, dose strength, dose interval) for 12 weeks prior to screening and nochange in that regimen should be anticipated for the entire duration of this study (ie, from screening to final follow-up visit).

5. Confirmed diagnosis or NASH or evidence of hepatic cirrhosis, based on clinicalassessment (eg, physical examination), historical liver biopsy or other priorimaging study, or a liver stiffness value ≥ 14 kPa during the FibroScan® examinationat screening.