Sting’s fortunes wax and wane

The lifting yesterday of the FDA’s clinical hold over Mersana’s anti-HER2 antibody-drug conjugate XMT-2056, which carries a Sting agonist payload, appeared to provide yet more impetus to the Sting mechanism, which has been enjoying a recent resurgence in interest. However, this morning GSK curbed the enthusiasm by revealing the discontinuation of its own Sting agonist project, GSK3745417. This had been in phase 1 trials for solid tumours and myeloid malignancies, but GSK said it was being removed from the pipeline. Also discontinued is the UK company’s anti-Lag3 MAb encelimab (GSK4074386), the result of a collaboration between AnaptysBio and Tesaro; GSK had acquired the latter back in 2018. This project was in two phase 1 trials, but both dated from before the acquisition, listing Tesaro as primary sponsor, and it seems GSK never started any encelimab studies of its own. This is despite Bristol Myers Squibb’s Opdualag showing significant potential to expand the activity of PD-(L)1 blockade, a fact that has spurred rival Lag3-directed work at Merck & Co, Regeneron and others.