iTeos and GSK to drop belrestotug + dostarlimab collaboration

Belgian clinical-stage biotech iTeos Therapeutics (Nasdaq: ITOS) saw its shar leap18.6% to $8.20 today, despite posting disappointing results for a leading program and decision to discontinue GALAXIES Lung-201, the Phase II platform study sponsored by iTeos’ development partner GSK (LSE: GSK) assessing the belrestotug + dostarlimab doublet in previously untreated, unresectable, locally advanced or metastatic PD-L1 high non-small cell lung cancer (NSCLC).

The GALAXIES Lung-201 data continued to demonstrate clinically meaningful improvements in the trial’s 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 in the belrestotug + dostarlimab combination cohorts versus dostarlimab monotherapy. Additionally, an interim analysis of the GALAXIES H&N-202 Phase II trial showed a trend below the meaningful threshold for ORR in the belrestotug combination cohorts versus. dostarlimab monotherapy in PD-L1 positive head and neck squamous cell carcinoma.

Based on these results, iTeos and GSK have made the decision to terminate the belrestotug development program and end the collaboration, marking another project to join the TIGIT graveyard. The collaboration had the potential to earn iTeos $2 billion.