Regular Monitoring Ongoing Monitoring 
Regular comprehensive and reproducible evaluation of disease compartments is recommended for all patients. The indicated frequency of monitoring depends on whether a patient is taking enzyme replacement therapy (ERT), and whether those patients have met therapeutic goals. All patients should be evaluated if there has been a dosing change or a significant clinical complication has occurred.
Download the Gaucher Registry Monitoring Guidelines (PDF).

Biochemical Markers
Chitotriosidase, an enzyme secreted by activated macrophages, is the most studied biomarker of Gaucher disease burden. Chitotriosidase activity is elevated in the sera of patients with Gaucher disease. Chitotriosidase activity has been shown to decrease with ERT in a dose-dependent manner and to correlate with improvement in hematologic and visceral parameters, but a clear correlation between clinical status and change in chitotriosidase level has not been established.
Values are variable between patients and a small proportion of patients (6%) do not have serum chitotriosidase because of a mutation. Single measurements of chitotriosidase activity are not clinically relevant; only serial measurements have prognostic value. Serial increases in serum chitotriosidase activity may be an early indicator of clinical relapse, including after dosage reduction or treatment interruption. Chitotriosidase levels are interpreted in conjunction with clinical assessments.
Additional or alternative biomarkers that are elevated in Gaucher disease are angiotensin-converting enzyme (ACE) and tartrate-resistance acid phosphatase (TRAP). ACE is a nonspecific indicator of lipid storage. TRAP, distinguished from total acid phosphatase, is often higher in the presence of active bone disease.
Important Safety Information
Approximately 15% of patients have developed immune responses (antibodies). These patients have a higher risk of an allergic reaction (hypersensitivity). Use Cerezyme® (imiglucerase for injection) carefully if you have had an allergic reaction to the product in the past. Symptoms suggestive of allergic reaction happened in 6.6% of patients, and include anaphylactoid reaction (a serious allergic reaction), itching, flushing, hives, an accumulation of fluid under the skin, chest discomfort, shortness of breath, coughing, cyanosis (a bluish discoloration of the skin due to diminished oxygen), and low blood pressure. Side effects related to Cerezyme administration have been reported in less than 15% of patients. Each of the following events occurred in less than 2% of the total patient population. Reported side effects include nausea, vomiting, abdominal pain, diarrhea, rash, fatigue, headache, fever, dizziness, chills, backache, and rapid heart rate. Because Cerezyme therapy is administered by intravenous infusion, reactions at the site of injection may occur: discomfort, itching, burning, swelling or uninfected abscess. Cerezyme is available by prescription only. For more information, consult your physician. To learn more, please see full product information (PDF), or contact Genzyme at 1-800-745-4447.

References
Weinreb NJ, Aggio MC, Andersson HC, et al. Gaucher disease type 1: Revised recommendations on ealuations and monitoring for adult patients. Semin Hematol. 2004;41(4 suppl 5):15-22.
Hollak CE, van Weely S, van Oers MH, Aerts JM. Marked elevation of plasma chitotriosidase activity. A novel hallmark of Gaucher disease. J Clin Invest. 1994;93:1288-1292
Aerts JM, Hollak CE Plasma and metabolic abnormalities in Gaucher's disease. Baillieres Clin Haematol. 1997;10:691-709.
Hollak CE, Maas M, Aerts JM. Clinically relevant therapeutic endpoints in type I Gaucher disease. J Inherit Metab Dis. 2001;24(Suppl 2):97-105.
Casal JA, Lacerda L, Perez LF, et al. Relationships between serum markers of monocyte/macrophage activation in type 1 Gaucher's disease. Clin Chem Lab Med. 2002;40:52-55.
Czartoryska B, Tylki-Szymanska A, Lugowska A. Changes in serum chitotriosidase activity with cessation of replacement enzyme (cerebrosidase) administration in Gaucher disease. Clin Biochem. 2000;33:147-149.
Cabrera-Salazar M, O'Rourke E, Henderson N, Wessel H, Barranger J. Correlation of surrogate markers of Gaucher disease. Implications for long-term follow up of enzyme replacement therapy. Clin Chim Acta. 2004;344:101-107.
Giraldo P, Cenarro A, Alfonso P, et al. Chitotriosidase genotype and plasma activity in patients with type 1 Gaucher's disease and their relatives (carriers and non-carriers). Haematologica. 2001;86:977-984.
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