Efficacy and Safety Study of RAGWITEK™ (MK-3641) in Children With Ragweed-Induced Rhinoconjunctivitis With or Without Asthma (MK-3641-008)

Inclusion Criteria:

- Is between the ages of 4 and 17 years (inclusive) at enrollment in this study and is
at least 5 years old at randomization

- Has a clinical history of significant ragweed pollen-induced allergic
rhinitis/rhinoconjunctivitis of ≥1 year (at least 1 season for ages 4 to 6 years) or
≥2 years (at least 2 seasons for ages 7 to 17 years) duration diagnosed by a physician
(with or without asthma) and have received treatment for the condition during the
previous ragweed season

- If female, agrees to remain abstinent or use (or have their partner use) an acceptable
method of birth control within the projected duration of the study.

Exclusion Criteria:

- Has a clinical history of symptomatic seasonal allergic rhinitis (and/or asthma) due
to another allergen, which has required regular medication during, or potentially
overlapping, the ragweed season

- Has a clinical history of significant symptomatic perennial allergic rhinitis and/or
asthma due to an allergen to which the subject is regularly exposed during the ragweed
season which would interfere with assessment of the treatment effect

- Has any nasal condition that could confound the efficacy or safety assessments (e.g.,
nasal polyposis).

- Has asthma requiring high daily doses of inhaled corticosteroids within the 6 months
prior to the Screening Visit

- Has severe, unstable, or uncontrolled asthma, as judged by the clinical investigator,
or has experienced a life-threatening asthma attack or an occurrence of any clinical
deterioration of asthma that resulted in emergency treatment, hospitalization due to
asthma, or treatment with systemic corticosteroids (but allowing short-acting beta
agonists) at any time within the last 3 months prior to the Screening or Randomization
Visits

- Has a history of anaphylaxis with cardiorespiratory symptoms with prior immunotherapy,
unknown cause, or inhalant allergen

- Has a diagnosis of eosinophilic esophagitis

- Has a history of chronic urticaria and/or chronic angioedema

- Has a clinical history of chronic sinusitis during the 2 years prior to the Screening
or Randomization Visits

- Has current severe atopic dermatitis

- Has a history of allergy, hypersensitivity, or intolerance to the ingredients of the
study drug (except for Ambrosia artemisiifolia), rescue medications, or
self-injectable epinephrine

- Has previously received MK-3641

- Has previously been randomized into this study

- Is participating in any other clinical study or plans to participate in another
clinical study during the duration of this study