This is a study to determine the safety of CDX-0159 in patients with Cold Contact Urticaria, Symptomatic Dermographism, or Cholinergic Urticaria.

This study is an open label Phase 1 study evaluating the safety, pharmacokinetics, and pharmacodynamics of a single dose of CDX-0159 in patients with Cold Contact Urticaria, Symptomatic Dermographism, or Cholinergic Urticaria who remain symptomatic despite treatment with antihistamines. Twenty patients with Cold Contact Urticaria, ten patients with Symptomatic Dermographism, and ten patients with Cholinergic Urticaria will be enrolled in four separate cohorts for a total of 40 patients.

Prospective patients will be screened with tests in clinic as well as daily at home diaries for 2 weeks prior to enrollment. CDX-0159 will be administered intravenously on Day 1. Post-treatment, patients will be followed for 12 weeks with an optional longer term follow up period.

Key Inclusion Criteria:

1. Diagnosis of Cold Contact Urticaria, Symptomatic Dermographism, or Cholinergic Urticaria which does not respond to antihistamines

   • Diagnosis for ≥ 3 months; symptoms of both hive (wheal) and itch/burning/painful sensation despite concurrent use of anti-histamines
   • During screening, in clinic, for Cold Contact Urticaria, patients must have a positive cold stimulation test, for Symptomatic Dermographism, patients must have a positive FricTest®, and for Cholinergic Urticaria, patients must have a positive pulse-controlled ergometry (PCE) provocation test
   • On stable dose of antihistamines

2. Other than a diagnosis of Cold Contact Urticaria, Symptomatic Dermographism, or Cholinergic Urticaria, no other conditions which would introduce additional risk factors or would interfere with the study procedures, as determined by the investigator, based on a medical evaluation

3. Female and male patients must use highly effective contraception from the time of the screening visit and for at least 150 days after receipt of study treatment

4. Willing and able to comply with all study requirements and procedures including completion of a daily medication diary and questionnaires

Key Exclusion Criteria:

1. A clearly defined diagnosis of hives or angioedema other than chronic urticaria.
2. Receipt of prior biologic therapy (e.g.: omalizumab, dupilumab, ligelizumab) within past 3 months
3. Treatment with immunosuppressives (e.g. systemic corticosteroids, cyclosporine, methotrexate, dapsone, cyclophosphamide, tacrolimus and mycophenolate mofetil, hydroxychloroquine or others) within 4 weeks or 5 half lives
4. Active COVID-19 infection
5. HIV, hepatitis B or hepatitis C infection

There are additional criteria that your study doctor will review with you to confirm you are eligible for the study.