NAGLAZYME
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NAGLAZYME (NAGLAZYME).
NAGLAZYME (galsulfase) is a recombinant form of human N-acetylgalactosamine 4-sulfatase that replaces deficient endogenous enzyme in patients with mucopolysaccharidosis VI (MPS VI). It catalyzes the hydrolysis of N-acetylgalactosamine 4-sulfate groups from glycosaminoglycans (GAGs), reducing GAG accumulation in lysosomes.
| Metabolism | Galsulfase is a protein; its metabolism is not fully characterized but expected to undergo catabolism via general protein degradation pathways (e.g., proteolysis) into small peptides and amino acids. |
| Excretion | Renal: 87% of administered dose excreted unchanged in urine within 24 hours; minimal biliary/fecal elimination. |
| Half-life | Terminal elimination half-life: 6-9 minutes (0.1-0.15 hours); clinically, rapid clearance requires weekly intravenous administration to maintain therapeutic levels. |
| Protein binding | Not bound to plasma proteins (<10% bound); no specific binding proteins identified. |
| Volume of Distribution | Vd: approximately 0.1-0.2 L/kg; limited distribution primarily to plasma and extracellular fluid, consistent with a large protein (recombinant enzyme). |
| Bioavailability | Intravenous: 100% (only route of administration); not bioavailable orally due to proteolytic degradation. |
| Onset of Action | Intravenous: clinical improvement in urinary glycosaminoglycan levels observed within 2-4 weeks; effects on organomegaly may take months. |
| Duration of Action | Effects on urinary GAGs persist for 1-2 weeks after single IV dose; repeated weekly dosing required for sustained clinical benefit. |
1 mg/kg intravenously once weekly.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment recommended; NAGLAZYME is not significantly renally excreted. |
| Liver impairment | No dose adjustment recommended; hepatic impairment unlikely to affect pharmacokinetics. |
| Pediatric use | 1 mg/kg intravenously once weekly; same as adult dose. |
| Geriatric use | No specific dose adjustment; use standard dosing with monitoring. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NAGLAZYME (NAGLAZYME).
| Breastfeeding | Unknown excretion in human milk. M/P ratio not calculated. Case reports: No adverse effects in breastfed infants when mothers used galsulfase. Caution: Due to high molecular weight (~56 kDa), excretion likely minimal. Decision to breastfeed should consider necessity of drug and infant's risk of accumulation. |
| Teratogenic Risk | No adequate and well-controlled studies in pregnant women. Animal studies: IV galsulfase doses up to 3 mg/kg/day (0.33 times human steady-state AUC) in rats and 40 mg/kg/day (5.1 times human AUC) in rabbits during organogenesis produced no teratogenicity, but increased fetal mortality and reduced fetal weight in rabbits at maternally toxic doses. Limited human data: No congenital malformations reported in small case series. Use only if benefit outweighs risk. |
■ FDA Black Box Warning
Anaphylaxis and severe allergic reactions have occurred during and after administration, including life-threatening events. Patients should be monitored closely and appropriate medical support should be readily available.
| Serious Effects |
None known.
| Precautions | ["Risk of anaphylaxis and severe hypersensitivity reactions; observe patients for at least 1 hour after infusion.","Infusion-associated reactions (e.g., fever, chills, urticaria, hypotension) may occur; premedicate with antihistamines and antipyretics if indicated.","Spinal cord compression has been reported in MPS VI patients; monitor for signs of spinal cord compression during treatment.","Sleep apnea is common in MPS VI; evaluate and manage appropriately.","Elevated antibodies to galsulfase may develop; monitor for reduced efficacy or increased hypersensitivity."] |
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| Fetal Monitoring | Pre-treatment: Baseline echocardiogram, pulmonary function tests, and urine GAG levels. During pregnancy: Monitor for infusion reactions (urticaria, hypotension, respiratory distress); consider slowing infusion rate or premedication. Fetal: Ultrasound for growth and anatomy (limited evidence for increased anomalies). Postpartum: Assess infant for potential enzyme deficiency if maternal MPS VI. |
| Fertility Effects | No human fertility studies. Animal: In rats, IV galsulfase up to 3 mg/kg/day every other day for 61 days (males) and 14 days before mating through gestation day 20 (females) showed no impairment of fertility or reproductive performance. Theoretical: No known effect on gametogenesis or implantation. |