Pharma BD Deal Intelligence
GSK and iTeos's TIGIT bet went bust: the $625M upfront on belrestotug delivered nothing after Phase 2 lung and head-and-neck data missed, GSK walked in May 2025, and iTeos wound down the company entirely.
GSK joins chase for hot cancer target TIGIT, paying iTeos $625M upfront in new alliance for EOS-448 anti-TIGIT antibody.
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…
iTeos announces corporate wind-down following termination of the GSK belrestotug collaboration; severance and program/clinical wind-down charges disclosed.
Source summaries from our enrichment pipeline; follow links for originals.
All 6 sources with sentiment breakdown →
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.
EOS-448 (belrestotug) is a Fc-enabled anti-TIGIT monoclonal antibody being developed for advanced solid tumors in combination with PD-1 blockade. The competitive landscape groups by MOA class: anti-TIGIT monoclonal antibodies (direct), anti-PD-(L)1 checkpoint inhibitors (backbone partners), and adjacent novel checkpoints (LAG-3, TIM-3). In the anti-TIGIT class, Roche/Genentech's tiragolumab is the most advanced competitor, with mixed Phase 3 readouts including SKYSCRAPER-01 (NSCLC, missed PFS) and SKYSCRAPER-02 (SCLC, missed). Merck's vibostolimab (MK-7684) is in Phase 3 combined with pembrolizumab (KeyVibe program) across NSCLC, melanoma, and SCLC. Gilead/Arcus' domvanalimab is in multiple Phase 3 trials (STAR-121 NSCLC, STAR-221 gastric) partnered with zimberelimab. AstraZeneca's rilvegostomig (PD-1/TIGIT bispecific) and BeiGene's ociperlimab round out the late-stage field. The critical backbone class is dominated by Merck's Keytruda (pembrolizumab, ~$29.5B 2024 sales), BMS' Opdivo (nivolumab, ~$9.3B 2024), and Roche's Tecentriq (atezolizumab). Adjacent novel checkpoint anchors include BMS' Opdualag (nivolumab + relatlimab, LAG-3). Commercial takeaway: the anti-TIGIT class remains unvalidated after multiple Phase 3 misses, meaning belrestotug's franchise threat ranking depends on whether GSK/iTeos can deliver the first unambiguously positive Phase 3 readout; class economics remain a binary bet.
GSK paid $625M upfront for co-development of belrestotug (EOS-448), anti-TIGIT antibody.
Belrestotug failed to show meaningful PFS in NSCLC Phase 2. Head and neck Phase 2 also below threshold. All cohorts ending.
TIGIT class broadly failing across industry. GSK lost $625M upfront. Phase 3 enrollment stopped.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| GlaxoSmithKline plc / iTeos Therapeutics S.A. (this deal) | 2021 | $2.1B | 28 |
| GlaxoSmithKline plc / Theravance, Inc. | 2012 | $213M | 82 |
| GlaxoSmithKline plc / Tesaro Inc. | 2018 | $5.1B | 79 |
| GlaxoSmithKline plc / Pfizer Inc. (Consumer Healthcare Division) | 2018 | $12.7B | 76 |
| GlaxoSmithKline plc / Novartis Consumer Healthcare JV | 2018 | $13.0B | 74 |
| GlaxoSmithKline plc / ID Biomedical Corporation | 2005 | $1.4B | 64 |
| GlaxoSmithKline plc / Vir Biotechnology Inc. | 2020 | $595M | 51 |
← Browse all deals · How we score deals
More: 2021 deals · GlaxoSmithKline plc deals · Oncology deals