Study to Investigate Etokimab (ANB020) Activity in Adult Participants With Peanut Allergy

The purpose of this study is to determine etokimab safety, tolerability and activity in adult participants with peanut allergy.

This is a multi-center, randomized, double-blind, placebo-controlled, proof of concept study to assess the safety and tolerability of etokimab in adult participants with peanut allergy.

Eligibility Criteria:
Inclusion Criteria:

* Male and female participants with age \> 18 years and able to give informed consent.
* Participants with a confirmed clinically allergic response to peanut.
* Positive clinical reaction during the peanut oral food challenge and no clinical reaction during the placebo challenge
* Positive peanut allergy skin prick test \> 3 millimeters (mm) of the negative control and detectable serum peanut-specific Immunoglobulin E (IgE) levels by ImmunoCAP testing.
* Body mass index (BMI) of 18 to 36 kilogram per square meter (kg/m\^2) inclusive) and total body weight \> 50 kg (110 lb). BMI = weight (kg)/(height \[m\^2\]).
* Willing and able to comply with the study protocol requirements.
* Have the ability to read and understand the study procedures and have the ability to communicate meaningfully with the Investigator and staff.
* Women of childbearing potential, must have a negative serum pregnancy test at screening and Day 1, and be surgically sterile or using an acceptable method of contraception throughout the study and for 15 weeks after the last administration of investigational product. Postmenopausal participants defined as (1) aged over 45 years with at least 1 year of amenorrhea and levels of follicle stimulating hormone over 20 international units per liter (IU/L) or (2) aged over 50 years with at least 1 year of amenorrhea.
* Male participants must be willing to use effective methods of contraception during the entire study period and for 15 weeks after the last administration of investigational product.

Exclusion Criteria:

* Have concomitant dermatological or medical condition(s) which may interfere with the Investigator's ability to evaluate the participant's response to the investigational product.
* Have experienced severe life-threatening anaphylactic reactions to peanuts within 6 months before screening (i.e., requiring an intensive care unit \[ICU\] admission).
* Positive clinical reaction observed during the placebo oral food challenge.
* Participation in any interventional study for the treatment of peanut and/or food allergies in the 12 months before screening.
* Have received any investigational product or been part of any interventional clinical study within a period of 3 months or 5 half-lives (whichever is longer) before screening.
* Have received systemic corticosteroids, nonsteroidal, immunosuppressant, or immunomodulating drugs treatments within 2 weeks before screening.
* Use of beta blockers, angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, or calcium channel blockers within 2 weeks before screening.
* History of ischemic cardiovascular diseases.
* Use of biologics within 6 months before screening or participant is in build-up phase of allergen immunotherapy (excluding peanut) and has not reached maintenance dose.
* Have received antibiotic treatment within 1 week before screening.
* Have a history of hypersensitivity or allergic reactions following infusions of human blood or blood components.
* Have a history of hypersensitivity or allergic reactions a component of etokimab formulation or the inactive ingredients (excipients).
* If female, are pregnant or lactating, or intend to become pregnant during the study period.
* Current diagnosis of asthma requiring Global Initiative for Asthma Assessment (GINA) Step 4 or higher treatment or asthma partially controlled or uncontrolled according to GINA classifications in the last three months before screening.
* History of a life threatening asthma attack within 1 year before screening (example: requiring an intensive care unit admission, intubation with mechanical ventilation).
* Other significant medical conditions that in the opinion of the Principal Investigator, prevent participation in the study.
* History of drug, alcohol or other substance abuse, or other factors limiting the ability to cooperate and to comply with the study protocol.
* Have any other physical, mental, or medical conditions which, in the opinion of the Investigator, make study participation inadvisable or could confound study assessments.
* Receipt of a live attenuated vaccine within 4 weeks before screening.
* Planned surgery during the study or 30 days before screening.