Migalastat

Breast Feeding; Lactation; Alpha-Galactosidase; Enzyme Inhibitors;

EMA approved medicines: Human medicine

In placebo-controlled trials, liver test abnormalities were rare and no more common with migalastat than with placebo treatment. What abnormalities occurred were mild and resolved spontaneously without need for dose interruption. During these premarketing clinical trials and since its more widespread clinical availability, no instances of acute liver injury with jaundice have been reported attributable to migalastat. However, the total clinical experience with its use has been limited.

A - Alimentary tract and metabolism

QA - Alimentary tract and metabolism

In general, treatment in patients with migalastat in Phase 2 pharmacodynamic trials resulted in increases in endogenous alpha-galactosidase (alpha-Gal A) activity in white blood cells, as well as in skin and kidney for the majority of patients. In patients with amenable galactosidase alpha gene (GLA) mutations, globotriaosylceramide (GL-3) levels tended to decrease in the urine and in the kidney interstitial capillaries. In an in vitro assay (HEK-293 assay), Human Embryonic Kidney (HEK-293) cell lines were transfected with specific GLA variants (mutations) which produced mutant alpha-Gal A proteins. In the transfected cells, amenability of the GLA variants was assessed after a 5-day incubation with 10 micromol/L migalastat. A GLA variant was categorized as amenable if the resultant mutant alpha-Gal A activity (measured in the cell lysates) met two criteria: 1) it showed a relative increase of at least 20% compared to the pre-treatment alpha-Gal A activity, and 2) it showed an absolute increase of at least 3% of the wild-type (normal) alpha-Gal activity. The in vitro assay did not evaluate the trafficking of the mutant alpha-Gal A proteins into the lysosome or the dissociation of migalastat from the mutant alpha-Gal A proteins within the lysosome. Also, the in vitro assay did not test whether a GLA variant causes Fabry disease or not.

Fabry disease is a progressive X-linked lysosomal storage disorder that affects males and females. Fabry disease-causing mutations occur in the galactosidase alpha (GLA) gene and result in a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-Gal A) that is required for glycosphingolipid substrate (GL-3 and lyso-Gb3) metabolism. Reduced alpha-Gal A activity is, therefore, associated with the progressive accumulation of glycosphingolipid substrate in vulnerable organs and tissues, which ultimately leads to the morbidity and mortality associated with Fabry disease. Migalastat is a pharmacological chaperone that reversibly binds to the active site of the alpha-galactosidase A (alpha-Gal A) protein (encoded by the galactosidase alpha gene, GLA), which is deficient in Fabry disease. This binding stabilizes alpha-Gal A allowing its trafficking from the endoplasmic reticulum into the lysosome where it exerts its action. In the lysosome, at a lower pH and at a higher concentration of relevant substrates, migalastat dissociates from alpha-Gal A allowing it to break down the glycosphingolipids globotriaosylceramide (GL-3) and globotriaosylsphingosine (lyso-Gb3). Certain GLA variants (mutations) causing Fabry disease result in the production of abnormally folded and less stable forms of the alpha-Gal A protein which, however, retain enzymatic activity. Those GLA variants, referred to as amenable variants, produce alpha-Gal A proteins that may be stabilized by migalastat thereby restoring their trafficking to lysosomes and their intralysosomal activity. The GLA mutations that are amenable and not amenable to treatment with migalastat are regularly maintained and updated on online sites that are readily accessible by healthcare providers.

With absorption occurring largely in the gut, the absolute bioavailability (AUC) for a single oral 150 mg migalastat hydrochloride dose or a single 2-hour 150 mg intravenous infusion was approximately 75% and Tmax was approximately 3 hours. Plasma migalastat exposure (AUC0-∞) and Cmax demonstrated dose-proportional increases at migalastat hydrochloride oral doses from 50 mg to 1,250 mg (doses from 0.5 to 8.3-fold of the approved recommended dosage). Migalastat administered with a high-fat meal (850 calories; 56% from fat), or 1 hour before a high-fat or light meal (507 calories; 30% from fat), or 1 hour after a light meal, resulted in significant reductions of 37% to 42% in mean total migalastat exposure (AUC0-∞) and reductions of 15% to 39% in mean peak migalastat exposure (Cmax) compared with the fasting state.

In a mass balance study in healthy male subjects, following oral administration of 123 mg [14C]-migalastat, approximately 77% of the total radiolabeled dose was recovered in urine and 20% of the total radiolabeled dose was recovered in feces with an overall total recovery of 98% within 96 hours post-dose. In urine, unchanged migalastat accounted for 80% of the radioactivity, which equates to 62% of the administered dose. In feces, unchanged migalastat was the only drug-related component. In plasma, unchanged migalastat accounted for approximately 77% of the plasma radioactivity, and three dehydrogenated O-glucuronide conjugated metabolites, M1 to M3, together accounted for approximately 13% of the plasma radioactivity, none of which comprised more than 6% of the radiolabeled dose. Approximately 9% of the total radioactivity in plasma was unassigned.

In healthy volunteers, the volume of distribution (Vz/F) of migalastat following ascending single oral doses (25-675 mg migalastat HCl) ranged from 77 to 133 L, indicating it is well distributed into tissues and greater than total body water (42 liters).

Following ascending single oral doses (25-675 mg migalastat hydrochloride), no trends were found for clearance (CL/F). At the 150 mg dose, CL/F was approximately 11 to 14 L/hr, while at 123 mg, the apparent clearance was calculated to be 12.5 L/hr.