GSK3174998 is an investigational antibody-based therapy being developed by GlaxoSmithKline in partnership with Merck, for the treatment of advanced or returning solid tumors.

How GSK3174998 works

GSK3174998 is a monoclonal antibody (a protein that binds to specific molecules) that specifically binds to OX40, a receptor protein expressed on the surface of activated T-cells (both helper T-cells and killer T-cells).

When injected into the bloodstream of patients, GSK3174998 selectively binds to and activates OX40, which in turn promotes both the proliferation and survival of activated T-cells. Therefore, GSK3174998 induces a T-cell mediated immune response against cancer cells, leading to their death.

GSK3174998 in clinical trials

An open-label, non-randomized, multicenter Phase 1 study (NCT02528357) is recruiting participants in the U.S., France, and the Netherlands with advanced or returning solid tumors that have progressed after standard treatment.

The trial was designed to evaluate the safety, tolerability, and preliminary clinical activity of GSK3174998 as a single agent (monotherapy) and in combination with Keytruda (pembrolizumab). Keytruda blocks the interaction of the programmed death-1 (PD-1) receptor with its ligands, PD-L1 and PD-L2, resulting in the activation of an immune response against cancer cells.

The study aims to enroll about 180 patients with different tumor types (non-small cell lung cancer, squamous cell carcinoma of the head and neck, renal cell carcinoma, melanoma, bladder, soft tissue sarcoma, triple-negative breast cancer, and colorectal cancer).

It will be conducted in two parts. Part 1 will evaluate the safety, tolerability, and maximum tolerated dose of GSK3174998 as a single agent in escalating doses administered every three weeks for up to 48 weeks. After a dose has been identified that is both tolerable and demonstrates clinical activity in part 1, enrollment for part 2 may begin. In part 2, escalating doses of GSK3174998 will be evaluated in combination with a fixed dose of Keytruda (200 mg) administered every three weeks for up to two years.

The post-treatment follow-up period will include disease assessments every 12 weeks. The study is expected to be completed by January 2020.


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