Inclusion Criteria:

Participant must be at least 6 years of age (or the minimum legal age for adolescents in the country of the investigational site) at the time of signing the informed consent.

Participants with the diagnosis of AFRS adapted from criteria by Bent and Kuhn (meeting all):

• IgE mediated inflammatory response to fungal hyphae (specific IgE serology or skin test) Evidence of sensitization to fungus by skin testing (at screening or documented historical positive skin test in the previous 12 months), or positive fungal-specific IgE in serum at screening.
• Nasal polyposis confirmed by nasal endoscopy at screening.
• Characteristic CT signs to be performed during screening period and can include any of the below signs as assessed by central reader:
  • hyperdensities
  • bony demineralization
  • bone erosion of sinus
• Eosinophilic mucin/mucus identified within 5 years prior to screening or at

  screening with or without positive fungal stain

AFRS patients with the following:

• An endoscopic NPS of at least 2 out of 4 for unilateral polyps or 3 out of 8 for bilateral polyps at Visit 1 (central reading) and Visit 2 (local reading) and,
• Sinus opacification in CT scan with an LMK score of 9 for patients with unilateral polyps or 12 for patients with bilateral polyps during screening period and,

Body weight ≥15 kg

Exclusion Criteria:

• Patients with nasal conditions/concomitant nasal diseases making them non-evaluable at Visit 1 or for the primary efficacy
• Nasal cavity malignant tumor and benign tumors.
• Known of fungal invasion into sinus tissue.
• Severe concomitant illness(es) that, in the investigator's judgment, would adversely affect the patient's participation in the study
• Active tuberculosis or non-tuberculous mycobacterial infection, or a history of incompletely treated tuberculosis unless documented adequately treated.
• Diagnosed active endoparasitic infections; suspected or high risk of endoparasitic infection
• Known or suspected immunodeficiency
• Active chronic or acute infection requiring treatment with systemic antibiotics, antivirals, or antifungals within 2 weeks before the Screening Visit 1 or during the screening period.
• History of systemic hypersensitivity or anaphylaxis to dupilumab or any of its excipients.
• Treatment with commercially available dupilumab within 12 months, participation in prior dupilumab clinical trial, or discontinued dupilumab use due to adverse event.
• Patients who are treated with intranasal corticosteroid drops; intranasal steroid emitting devices/stents; nasal spray using exhalation delivery system, such as Xhance™, during screening period.
• Patients who are on intranasal corticosteroids (INCS) spray unless they have received stable dose for at least 4 weeks prior to Visit 1.
• Patients who have undergone sinus intranasal surgery (including polypectomy) within 6 months prior to Visit 1.
• Patients who have taken:
  • Biologic therapy/systemic immunosuppressant to treat inflammatory disease or autoimmune disease within 5 half-lives prior to Visit 1
  • Any investigational mAb within 5 half-lives prior to Visit 1
  • Anti-IgE therapy (omalizumab) within 4 months prior to Visit 1. - Treatment with a live (attenuated) vaccine within 4 weeks prior to Visit 1
• Leukotriene antagonists/modifiers unless patient is on a continuous treatment for at

  least 30 days prior to Visit 1.

• Initiation of allergen immunotherapy within 3 months prior to Visit 1 or a plan to begin therapy or change its dose during the screening or treatment period. - Patients received SCS during screening period. - Either intravenous immunoglobulin therapy and/or plasmapheresis within 30 days prior to Screening Visit (Visit 1).

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.