The goal of this clinical trial is to evaluate the safety, pharmacokinetics, and effectiveness of MY006, a therapy designed to prevent severe or potentially life-threatening allergic reactions caused by accidental peanut intake. In the first part of the study, adult participants receive one dose or two doses of MY006 or a placebo, administered by subcutaneous injection. The safety of MY006, including the number of adverse events, injection-site reactions, and immunogenicity, in these participants will be reviewed by an independent Safety Monitoring Committee and, if the safety is judged acceptable, the second part of the study will be started. In the second part of the study, adult and adolescent participants with peanut allergy receive one dose of MY006 or a placebo, administered by subcutaneous injection. Several weeks later, the participants are given a food peanut challenge to assess reactions and treatment effects. The duration of the study for participants is for up to 32 weeks.

Key Inclusion Criteria:

Part A - Single-ascending dose and multiple dose cohorts in healthy volunteers

1. Subject is male or female between 18 to 55 years of age, inclusive, at the screening visit.
2. Subject agrees voluntarily to participate, and is able to read and understand, and willing to sign, the Institutional Review Board/Independent Ethics Committee-approved informed consent form prior to performing any screening visit procedures.
3. Subject weight at screening and admission is between 45 kg and 100 kg, inclusive.
4. Subject has a body mass index between 18.0 and 30.0 kg/m2, inclusive, at screening visit.

Part B - Peanut-allergic patient cohorts

1. Participant and/or parent/legal guardian must be able to understand and provide informed consent and/or assent, as applicable.

2. Patient is male or female between 12 to 55 years of age, inclusive, at the screening visit.

3. Patient weight at screening and admission is between 40 kg and 100 kg, inclusive.

4. If patient is 12-17 years of age, their body mass index (BMI) must be above the 5th percentile and below the 95th percentile for age and sex at the screening visit. If patient is 18 years of age or above, their BMI must be between 18.0 and 30.0 kg/m2, inclusive, at the screening visit.

5. Patient has a history of allergy to peanut and meets all of the following criteria:

   1. Positive skin prick test (≥5 mm wheal greater than Placebo) to peanut; and
   2. Positive specific IgE (≥0.7 kUA/L) to peanut and Ara h 2 at screening determined by ImmunoCap; and
   3. Positive double-blinded challenge to peanut during the screening period, defined as experiencing dose-limiting symptoms at a single dose of ≤300 mg of peanut protein.

6. Patient is willing and able to avoid peanut-containing products and any other allergy-inducing foods known to the patient for the duration of study participation.

Key Exclusion Criteria:

Part A - Single-ascending dose and multiple dose cohorts in healthy volunteers

1. Subject has a clinically relevant history, as determined by the Principal Investigator or designee, or presence of respiratory, gastrointestinal, renal, hepatic, hematological, lymphatic, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, endocrine, and/or connective tissue diseases or disorders.

2. Subject has clinically significant abnormal vital signs, after 5 minutes or more of sitting rest, defined as any of the following:

   1. Systolic blood pressure ≥140 mmHg;
   2. Diastolic blood pressure ≥90 mmHg; and/or
   3. Heart rate ≥90 beats per minute.

3. Subject has any clinically significant abnormalities in rhythm, conduction, or morphology of the resting electrocardiogram (ECG) and/or any clinically significant abnormalities in the 12-lead ECG as considered by the Principal Investigator or designee that may interfere with the interpretation of QTc interval changes.

4. Subject has history of severe allergy/hypersensitivity, ongoing clinically significant allergy/hypersensitivity, as judged by the Principal Investigator or designee, known or suspected allergy to peanuts, and/or history of hypersensitivity to drugs with a similar structure or class.

Part B - Peanut-allergy patient cohorts

1. Patient has history of frequent or recent severe, life-threatening episodes of anaphylaxis or anaphylactic shock to peanut, as defined by more than 3 episodes of anaphylaxis within the past year and/or an episode of anaphylaxis within 60 days of screening.

2. Patient has uncontrolled or severe asthma/wheezing at screening, defined by one or more of the following criteria:

   1. Global Initiative for Asthma criteria regarding asthma control per latest guidelines;
   2. History of two or more systemic corticosteroid courses within 6 months of screening or one course of systemic corticosteroids within three months of screening to treat asthma/wheezing;
   3. Prior intubation/mechanical ventilation for asthma/wheezing;
   4. One hospitalization or emergency department visit for asthma/wheezing within 12 months of screening;
   5. Inhaled corticosteroid (ICS) dosing of >500 mcg daily fluticasone (or equivalent ICS based on the CoFAR Inhaled Corticosteroid Equivalency Tables); and/or
   6. Forced expiratory volume in one second (FEV1) <80% of predicted or FEV1/forced vital capacity <75%, with or without controller medications.

3. Patient has unstable exacerbated atopic disease (e.g., atopic dermatitis, urticaria, allergic rhinitis) defined by an episode of disease requiring initiation of systemic immunosuppressive or immunomodulatory treatment in the last 3 months.

4. Patient has current clinically significant cardiovascular, respiratory, neurologic, hepatic, hematopoietic, renal, gastrointestinal, or metabolic dysfunction unless currently controlled and stable as judged by the Principal Investigator.

5. Patient has abnormal vital signs, after 5 minutes or more of sitting rest, defined as any of the following:

   1. Systolic blood pressure ≥140 mmHg;
   2. Diastolic blood pressure ≥90 mmHg; and/or
   3. Heart rate ≥90 beats per minute.