Pilot Phase III Clinical Trial of JDP-205 IV Injection for Treatment of Acute Urticaria

Patients are eligible to be included in the study only if they meet all of the following criteria: Inclusion Criteria: * Male or female patients with a diagnosis of acute urticaria associated with an acute allergic reaction to a known (e.g. food, medication, insect bites) or unknown allergen who need treatment with an injectable antihistamine to alleviate their symptoms; * 18 years of age or older; * Be willing and able to give informed consent; * Patients with a Physician Pruritus Severity Score ≥ 1 (determined by the investigator); * Patients with an Extent of Urticaria/Erythema Score ≥ 1 (determined by the investigator). Exclusion Criteria: * Receipt of an investigational drug or device, within the past 30 days; * Patients in whom an antihistamine may be contraindicated (e.g. narrow angle glaucoma, symptomatic prostatic hypertrophy); * Patients who, in the opinion of the investigator, may not tolerate an IV injection of diphenhydramine 50 mg, or cetirizine 10 mg; * Receipt of any antihistamine (H1 antagonist) within the past 4 hours regardless of the route of administration, e.g. diphenhydramine, cetirizine, loratadine, fexofenadine, levocetirizine, desloratadine; * Receipt of an H2 antagonist within the past 12 hours; * Receipt of doxepin within the past 48 hours; doxepin is an antidepressant, but it also has antihistamine properties; * Receipt of steroids by the oral, IV, IM, or inhalational routes route within the past 48 hours to manage an acute allergic reaction; * Receipt of epinephrine (EpiPen or any other brand) within the past 1 hour; * Has known allergy to hydroxyzine, cetirizine or levocetirizine, or diphenhydramine; * Pregnancy or breastfeeding; * Patients who require epinephrine immediately to manage their acute allergic symptoms; * Patients who have an acute reaction to medication they are taking (e.g. antibiotics, ACE inhibitors, NSAIDs) and who cannot stop the medication; * Patients who, based on their medical history or in the opinion of the investigator, have chronic idiopathic urticaria, hereditary angioedema, urticaria refractory to antihistamines, or dermatological disease that interferes with evaluation of a therapeutic response; * Urticaria not associated with an acute allergic reaction; * Any condition that in the view of the investigator makes the subject unsuitable for enrollment in this study; * History of HIV or other known immunodeficiency; * Major medical or psychiatric illness, other than acute urticaria, at the time of presentation; * Inability to provide informed consent.