An Outpatient Study of the Efficacy of ARS-2 in Patients With Chronic Spontaneous Urticaria

Inclusion Criteria:

• Is a male or female between the ages of 18 and 65 years, inclusive.

• Has been clinically diagnosed with CSU and experiences an acute flare of moderate tosevere urticaria symptoms (itch and hive severity UAS score ≥ 2) approximately 1-2times a month or every other month consistently during the past year while on achronic treatment.

• Has been on a daily chronic treatment for ≥ 6 weeks.

• Is willing to use a smartphone study application to record study assessments andAEs.

• Has body weight more than 15 kilogram (kg).

• Has no medical history of clinically significant hypertension and cardiovasculardisease in the last 10 years

• If female, is not pregnant or breastfeeding based on a negative urine pregnancy testat baseline.

• Is able to communicate clearly with the Investigator and staff; able to read,complete questionnaires, and perform study procedures on the smartphone studyapplication.

• Is willing and able to provide written informed consent prior to participating inthe study.

• Controlled hypertension without beta blocker confirmed by the Investigator isacceptable.

• At screening, has stable vital signs in the following ranges (after 5 minutes ofrest):

• Systolic blood pressure (SBP) ≥90 and ≤140 milliliters of mercury (mmHg)

• Diastolic blood pressure (DBP) ≥50 and ≤90 mmHg

• Heart rate (HR) ≥45 and ≤100 beats per minute (bpm)

Exclusion Criteria:

• Has a history of clinically significant gastrointestinal, renal, hepatic,neurologic, hematologic, endocrine, oncologic, pulmonary, immunologic, psychiatric,or cardiovascular disease or any other condition which, in the opinion of theInvestigator, would jeopardize the safety of the subject or impact the validity ofthe study results.

• Has any clinically significant medical condition or PE finding as deemedinappropriate by the Investigator.

• Has abnormal cardiovascular exam at screening including any prior history ofmyocardial infarction or clinically significant abnormal electrocardiogram (ECG)

• Has had significant traumatic injury or major surgery within 30 days prior to studyscreening.

• Known hypersensitivity to any compound in the test product, or any other closelyrelated compound (e.g., dihydropyridine-derived molecules).

• Has participated in a clinical trial within 30 days prior to the first dose of studydrug.

• Has an immediate family member of the Investigator, or an employee of the studycenter, with direct involvement in the proposed study, or other studies under thedirection of the Investigator or study center or is in a dependent relationship witha study center employee who is involved in the conduct of this study (e.g., spouse,parent, child, sibling), or may consent under duress.