GSK and iTeos are the latest companies to scrap a jointly developed anti-TIGIT drug after it failed to demonstrate a meaningful benefit in two Phase II trials.
Belrestotug, a human IgG1 antibody created to bind with high-affinity T cell immunoglobulin and ITIM domains (TIGIT), was being developed as part of a partnership harnessed between the companies in June 2021.
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The companies announced on 13 May that they were slashing the programme after receiving new interim analyses from the Phase II GALAXIES Lung-201 (NCT05565378) and GALAXIES H&N-202 (NCT06062420) studies, which did not meet their efficacy endpoints.
Both trials were investigating the drug in combination with the PD-1 monoclonal antibody Jemperli (dostarlimab). However, the GALAXIES Lung-201 study was in patients with previously untreated, advanced/metastatic non-small-cell lung cancer (NSCLC). Meanwhile, the GALAXIES H&N-202 trial was in patients with PD-L1 positive recurrent/metastatic squamous cell carcinoma of the head and neck.
iTeos reported that while the GALAXIES Lung-201 trial demonstrated clinically meaningful improvements in the primary endpoint of objective response rate (ORR), however, the analysis did not meet established criteria for clinically meaningful improvements in the secondary endpoint of progression-free survival (PFS). Analysis from the GALAXIES H&N-202 trial showed a trend below the meaningful threshold for ORR in the combination cohort.
In a company statement, GSK says that due to the failures, the collaboration and all belrestotug study cohorts are ending. iTeos clarified that this includes enrolment in the ongoing GALAXIES Lung-301 Phase III trial.
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By GlobalDataiTeos’ president and chief executive officer Dr Michel Detheux said: “We are truly disappointed by the results from GALAXIES Lung-201. Following the analysis of the TIGIT data generated to date with GSK, we have made the mutual decision to discontinue the development of all ongoing TIGIT studies.”
GSK joins pharma giants dropping anti-TIGIT drugs
The news may come as a shock to the oncology field, as GSK and iTeos provided the first data for the GALAXIES Lung-201 study at the European Society for Medical Oncology (ESMO) Congress 2024 last September. The data seemed to show a positive trend with an ORR of between 63.3% and 76.7% versus 37.5% for Jemperli as a monotherapy.
The mechanism has proven challenging, with GSK and iTeos becoming the latest companies to terminate an anti-TIGIT asset.
Last month, BeiGene announced it was terminating development of ociperlimab, which it had been manufacturing as a treatment for lung cancer.
In December 2024, MSD scrapped the development of its anti-TIGIT antibody vibostolimab after the Phase III KeyVibe-003 and KeyVibe-007 trials met the pre-specified futility criteria for the primary endpoint of overall survival (OS) in patients with NSCLC. The company stopped the KeyVibe-008 trial last year.
In November 2024, Roche reported a failure with its candidate tiragolumab, which was being trialled in the Phase III Skyscraper-01 study. This came after earlier setbacks in the SKYSCRAPER-02 (NCT04256421) study and the Phase II/III SKYSCRAPER-06 (NCT04619797) trial.
Some anti-TIGIT programmes are still steaming ahead, including one by Gilead and Arcus Biosciences; who are investigating domvanalimab, and another by AstraZeneca with its PD-1/TIGIT bispecific antibody rilvegostomig.
