FDA Approves L-Glutamine Powder for the Treatment of Sickle Cell Disease

Approval was based on data from a randomized, double-blind, placebo-controlled, multi-center clinical trial (NCT01179217) enrolling 230 patients (5 to 58 years old) with sickle cell anemia or sickle β⁰-thalassemia who had two or more painful crises within the 12 months prior to enrollment. Eligible patients stabilized on hydroxyurea for at least 3 months, continued their therapy throughout the study. Patients were randomized to receive either L-glutamine or placebo for 48 weeks followed by three weeks of drug tapering.

Efficacy was demonstrated by a reduction in the number of sickle cell crises through Week 48 among patients who received L-glutamine compared to those receiving placebo. A sickle cell crisis was defined as an emergency room/medical facility visit for sickle cell disease-related pain treated with a parenteral narcotic or parenteral ketorolac. The occurrence of chest syndrome, priapism, and splenic sequestration were considered sickle cell crises. Over the 48-week period, patients receiving L-glutamine had a median of 3 sickle cell crises compared with a median of 4 crises for those receiving placebo. Treatment with L-glutamine also resulted in fewer hospitalizations due to sickle cell pain, fewer cumulative hospital days, and a lower incidence of acute chest syndrome.

The most common adverse reactions occurring in greater than 10% of patients treated with L-glutamine were constipation, nausea, headache, abdominal pain, cough, pain in extremity, back pain, and chest pain. Treatment discontinuation due to adverse reactions was reported in 2.7% (n=5) of patients receiving L-glutamine. These adverse reactions included one case each of hypersplenism, abdominal pain, dyspepsia, burning sensation, and hot flash.

The recommended dose of L-glutamine is 10 grams to 30 grams per day (based on body weight) taken orally, twice daily. See recommended dosing based on weight listed in the product label. Each dose should be mixed in 8 oz. (240 mL) of cold or room temperature beverage or 4 to 6 oz. of food before ingestion.

Full prescribing information is available (https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/208587s000lbl.pdf).

FDA previously granted Orphan Drug Designation to L-glutamine for this indication.  A description of FDA expedited programs is in the Guidance for Industry: Expedited Programs for Serious Conditions-Drugs and Biologics (http://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm358301.pdf).

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