The purpose of this study is to compare how two different formulations of the study medicine (GSK5784283) move through the body over time (pharmacokinetic [PK] study) in healthy adults. The aim of the study is to see how the body processes GSK5784283 and determine if the study medicine is safe, how well it is tolerated by the body and if the study medicines being tested work in the body in the same way.

Inclusion Criteria:

• Participants who are healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and ECG.
• Body weight greater than or equal (>=) 50 kilogram (kg) (110 pounds [lbs]) and body mass index within the range 19 to 30 kilogram per meter square (kg/m^2) (inclusive).
• A female participant is eligible to participate if she is a participant of non-childbearing potential (PONCBP) as specified in the protocol.
• Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the ICF and in this protocol.

Exclusion Criteria:

• Hypersensitivity- Participants with allergy/intolerance to any biologic therapy or any of the known excipients used in products administered subcutaneously
• History or presence of any clinically significant medical condition capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention or interfering with the interpretation of data.
• Any clinically relevant abnormal findings in physical examination, hematology, clinical chemistry, urinalysis, vital signs during screening period which in the opinion of the investigator, may put the subject at risk because of his/her participation in the study, or may influence the results of the study, or the subject's ability to participate in the study.
• Live vaccine(s) within 1 month prior to screening or plans to receive such vaccines during the clinical study.
• Treatment with biologic agents (such as monoclonal antibodies including marketed drugs) within 3 months or 5 half-lives (whichever is longer) prior to study intervention administration.
• Current smokers (tobacco and/or marijuana) or former smokers with a smoking history >10 pack-years and participants using vaping products, including electronic cigarettes.
• Regular alcohol consumption that exceeds the limits specified in the protocol
• Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the investigator or medical monitor, contraindicates participation in the clinical study.
• The QTc is the QT interval corrected for heart rate according to Fridericia's formula (QTcF), machine-read or manually over-read >450 millisecond (msec).

Study Sponsor will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/gsk-patient-level-data-sharing-july2025.pdf

Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or asset(s) with development terminated across all indications.

Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months, but an extension may be granted, when justified, for up to 6 months.