Nonprecipitous changes upon withdrawal from imiglucerase for Gaucher disease because of a shortage in supply

Because of an unpredicted and unavoidable shortage in global supplies of imiglucerase for Gaucher disease, we collected clinical and laboratory data from patients who were evaluated ≤ 6 months before drug withdrawal and then retested before/during reinstatement of therapy. Hemoglobin, platelet counts, and liver and spleen index volumes by ultrasound as well as chitotriosidase were evaluated as percent change over time and relative to dose-years of exposure to enzyme therapy. Deterioration was seen in all four clinical parameters and in chitotriosidase activity in most patients and even among patients who stopped for only 3. months. No patient consistently showed nondeterioration in all five parameters. Platelet counts were most sensitive to therapy withdrawal. There was no overt correlation between percent change in these parameters and dose-years of therapy. Although we no longer think that drug vacations should be considered as a form of maintenance for patients requiring enzyme therapy for Gaucher disease, but if necessary-for compelling personal reasons-one may be reassured that a short-term drug interruption is not likely to lead to irreversible complications or return to baseline values of critical clinical parameters.