Safety, Tolerability and Efficacy of Microsomal Triglyceride Protein (MTP) Inhibitor

This is a single center, open-label, Phase 2 clinical trial designed to evaluate the safety, tolerability, and pharmacodynamics of lomitapide in the treatment of patients with homozygous familial hypercholesterolemia (HoFH).

Patients are required to stop all lipid-lowering therapies, including apheresis, within 4 weeks prior to the Baseline visit and throughout the study. Patients are placed on a rigorous low-fat diet (<10% of energy from total dietary fat) at the Screening assessment; dietary counseling by a registered dietitian will be initiated at Screening and will continue at each subsequent study visit.

Patients initially receive 0.03 mg/kg of lomitapide orally every day for 4 weeks. Intra-patient dose escalation to 0.1 mg/kg, 0.3 mg/kg/day and 1.0 mg/kg/day occur every 4 weeks if specific protocol-defined stopping rules related to Grade 3 or 4 toxicities or serious adverse events (SAEs) do not apply.

The study includes 15 study visits over 22 weeks: a Screening visit (Visit 1) conducted within 2 weeks prior to dosing, a Baseline visit (Visit 2) conducted on Day 1 prior to the first dose, 12 visits conducted during the treatment period (Visits 3 through 14), and a Follow-up visit (Visit 15) conducted approximately 4 weeks after the last dose of lomitapide.

Screening and Baseline procedures include medical and medication history, physical examination, vital signs, 12-lead electrocardiogram (ECG), pulmonary function tests (PFTs), safety laboratory tests, fat soluble vitamin levels and a fatty acid profile. Nuclear magnetic resonance spectroscopy (NMRS) of the liver will be conducted at Baseline, at the end of each dosing period, and at the follow up visit to assess hepatic fat content. Baseline efficacy assessment includes a fasting lipid profile (TC, LDL-C [directly measured], VLDL-C, high density lipoprotein-cholesterol [HDL-C], triglycerides, and apolipoproteins [apo B, apo AI, apo AII, apo CIII, apo E] and Lp(a)).

Safety and lipid profile assessments are repeated during the treatment period and at the Follow-up visit conducted 28 days after the last dose of lomitapide.

Inclusion criteria

• Males and females ≥13 years of age
• Clinical diagnosis of HoFH AND one of the following (a, b, or c):

• Documented functional mutation in both LDL receptor alleles, OR
• Skin fibroblast LDL receptor activity <20% of normal, OR
• TC >500 mg/dL AND triglycerides < 300 mg/dL AND both parents with documented TC >250 mg/dL
• Body weight ≥40 kg
• Negative screening pregnancy test if female of child-bearing potential
• Subjects must be willing and able to comply with all study-related procedures
• Subjects must be willing and able to go off all lipid-lowering medications, dietary supplements (psyllium preparations) and LDL apheresis within 4 weeks prior to the Baseline visit until the end of the study.

Exclusion criteria

• Uncontrolled hypertension defined as: systolic blood pressure >180 mmHg, diastolic blood pressure >95 mmHg
• History of chronic renal insufficiency (serum creatinine >2.5 mg/dL)
• History of liver disease or abnormal LFTs at screening (>3x upper limit of normal [ULN])
• Any major surgical procedure occurring < 3 months prior to the screening visit
• Cardiac insufficiency defined by the New York Heart Association classification as functional Class III or Class IV
• History of a non-skin malignancy within the previous 5 years
• History of alcohol or drug abuse
• Participation in an investigational drug study within 6 weeks prior to the screening visit
• Serious or unstable medical or psychological conditions that, in the opinion of the Investigator, would compromise the patient's safety or successful participation in the study.