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# GSK Scraps Monoclonal Antibody Development for RA
- URL: https://www.fdaweb.com/gsk-scraps-monoclonal-antibody-development-for-ra/
- Published: 2022-10-27T12:00:00.000Z
- Updated: 2026-09-14T18:04:25.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5153070

GSK has abandoned plans to seek FDA approval for otilimab, an investigational monoclonal antibody targeting granulocyte-macrophage colony-stimulating factor (GM-CSF) as a treatment for moderate to severe rheumatoid arthritis (RA) in patients who did not respond to earlier treatments.

The company says it based its decision on data from a Phase 3 study called ContRAst-3, which did not demonstrate statistical significance on the primary endpoint of ACR20, a common improvement assessment in the core set of RA measures, in patients with inadequate responses to biologic disease modifying antirheumatic drugs or Janus Kinase inhibitors.

The company made the call to not seek approval despite two other studies having met their primary endpoint. “While the ContRAst-1 and ContRAst-2 trials met their primary endpoints, the efficacy demonstrated is unlikely to transform patient care for this difficult-to-treat patient population,” explains the company. “Assessment of efficacy and safety data from the ContRAst program is ongoing, however the limited efficacy demonstrated does not support a suitable benefit/risk profile for otilimab as a potential treatment for RA.”

GSK say optilimab works by inhibiting GM-CSF, a protein that plays a role in immune-mediated diseases, including RA. “GM-CSF acts on cells, including macrophages (an immune cell type that plays a key role in the inflammatory process), leading to inflammation, joint damage and pain,” it says. “Otilimab neutralizes the biological function of GM-CSF by blocking the interaction of GM-CSF with its cell surface receptor.”