Pharma BD Deal Intelligence

GlaxoSmithKline plc / iTeos Therapeutics S.A.

2021 · Co-Development · $2.1B · Complete

CALLED IT — OFF BY 22
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The coverage arc

Jun 14, 2021 MedCity News Bullish

GSK joins chase for hot cancer target TIGIT, paying iTeos $625M upfront in new alliance for EOS-448 anti-TIGIT antibody.

May 13, 2025 GSK Bearish

GSK and iTeos discontinuing belrestotug after phase 2 GALAXIES Lung-201 and H&N-202 interim analyses did not meet efficacy criteria; the collaboration and all…

May 27, 2025 iTeos Therapeutics 8-K (2025-05-27) Bearish

iTeos announces corporate wind-down following termination of the GSK belrestotug collaboration; severance and program/clinical wind-down charges disclosed.

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In June 2021 GSK paid iTeos Therapeutics $625M upfront (deal value up to ~$2.075B with $550M development/regulatory and $900M commercial milestones, plus equal US profit share and ex-US royalties) to co-develop and co-commercialize belrestotug (EOS-448), an Fc-active anti-TIGIT monoclonal antibody, for next-generation immuno-oncology combinations. On 13 May 2025 GSK and iTeos terminated the belrestotug program and ended the collaboration after the Phase 2 GALAXIES Lung-201 interim analysis (belrestotug + dostarlimab in first-line PD-L1-high NSCLC) failed to show clinically meaningful progression-free survival despite an improved objective response rate, and the GALAXIES H&N-202 head-and-neck cohort trended below the ORR threshold. All belrestotug-containing cohorts ended and new enrollment in the Phase 3 GALAXIES Lung-301 trial stopped; iTeos subsequently announced a corporate wind-down. The deal joins a long list of TIGIT-class clinical failures, with GSK's $625M upfront unrecovered.

Key facts

Related deals — scored

DealYearValueOutcome
GlaxoSmithKline plc / iTeos Therapeutics S.A. (this deal)2021$2.1B28
GlaxoSmithKline plc / Theravance, Inc.2012$213M82
GlaxoSmithKline plc / Tesaro Inc.2018$5.1B79
GlaxoSmithKline plc / Pfizer Inc. (Consumer Healthcare Division)2018$12.7B76
GlaxoSmithKline plc / Novartis Consumer Healthcare JV2018$13.0B74
GlaxoSmithKline plc / ID Biomedical Corporation2005$1.4B64
GlaxoSmithKline plc / Vir Biotechnology Inc.2020$595M51

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