On December 21, 2018, the Food and Drug Administration approved tagraxofusp-erzs (ELZONRIS, Stemline Therapeutics), a CD123-directed cytotoxin, for blastic plasmacytoid dendritic cell neoplasm (BPDCN) in adults and in pediatric patients 2 years and older.
Approval was based on a multicenter, multicohort, open-label, single-arm clinical trial (STML-401-0114; NCT 02113982) in patients with untreated or relapsed/refractory BPDCN. Patients received tagraxofusp-erzs at the recommended dose of 12 mcg/kg (see schedule below) In the pivotal cohort, seven (53.8%; 95% CI: 25.1, 80.8) of 13 patients with untreated BPDCN achieved complete response/clinical complete response after a median follow-up of 11.5 months. The median response duration was not reached. In the second cohort, of 15 patients with relapsed or refractory BPDCN, one patient achieved a complete response (duration 111 days) and one patient achieved a clinical complete response (duration 424 days).
Most common adverse reactions (incidence ≥ 30%) are capillary leak syndrome, nausea, fatigue, peripheral edema, pyrexia, and weight increase. Most common laboratory abnormalities (incidence ≥ 50%) are decreases in albumin, platelets, hemoglobin, calcium, and sodium, and increases in glucose, ALT and AST.
The recommended tagraxofusp-erzs dose and schedule is 12 mcg/kg administered intravenously over 15 minutes once daily on days 1 to 5 of a 21-day cycle.
FDA granted this application priority review and breakthrough therapy designation. This therapy also received orphan drug designation. A description of FDA expedited programs is in the Guidance for Industry: Expedited Programs for Serious Conditions-Drugs and Biologics.
Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System or by calling 1-800-FDA-1088.
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