A Study to Assess the Efficacy and Safety of GSK5784283 (Felcorekibart) Compared With Placebo in Participants With Chronic Rhinosinusitis With Nasal Polyps (CRSwNP)

Inclusion Criteria: * 18 years of age and older * Male or eligible female participants * Physician-diagnosed CRSwNP for greater than or equals to (\>=) 12 months before screening. * Have had at least one of the following at Visit 1: * Any documented history of Nasal surgery for the removal of NP (or contraindications/intolerance to Nasal surgery) * Have used at least 3 consecutive days of Systemic corticosteroid (SCS) or 1 intramuscular depot injectable dose (or contraindications/intolerance to SCS) in the previous 12 months (but not in the past 3 months before screening) for the treatment of NP. * Endoscopic bilateral NP score consistent with severe CRSwNP assessed by the investigator. * Symptoms of Chronic rhinosinusitis (CRS) * Presence of symptoms of CRS for at least 12 weeks prior to Visit 1 such as rhinorrhea and/or reduction or loss of smell and * Moderate to severe nasal congestion/blockade/obstruction at Visit 1 based on clinical assessment by the investigator. * Participants must have an elevated SNOT-22 score at screening. * Participants must be on daily treatment with intranasal corticosteroids (INCS) (including intranasal liquid steroid wash/douching) for at least the 8 weeks prior to screening. Exclusion Criteria: * As a result of medical interview, physical examination, or screening investigation the physician responsible considers the participant unfit for the study. * Have the following conditions:- Cystic fibrosis, Antrochoanal polyps, Nasal cavity tumor (malignant or benign), Fungal rhinosinusitis, Rhinitis medicamentosa, Hyper-eosinophilic syndrome (HES) Eosinophilic granulomatosis with polyangiitis (EGPA) or Churg-Strauss Syndrome or eosinophilic esophagitis, Helminth parasitic infection in the past 6 months unless treated and have responded to therapy. * Female who are pregnant * Known substance or alcohol abuse * Current smokers (including e-cigarettes) or ex-smokers of 6 months or less * Other significant medical conditions (eg immunogenicity, Human immunodeficiency virus \[HIV\], viral hepatitis, tuberculosis \[TB\], cardiac and liver disease) that could impact participants' safety or study outcomes. * Where nasal surgery is contraindicated * Nasal surgery in the past 6 months * Asthma exacerbation in the past 4 weeks.