First-in-human results with a novel pharmacological mechanism are especially interesting when they have a read-across to a recent biotech collaboration. Thus presentation of data for Merck & Co’s MK-4830 at Esmo yesterday was of relevance to followers of Jounce, which last year licensed its similarly acting JTX-8064 for $50m to Celgene. One confusing factor is that Merck describes MK-4830 as an anti-immunoglobulin-like transcript 4 MAb, whereas Jounce says JTX-8064 hits anti-leukocyte immunoglobulin-like receptor B2; the two names actually refer to the same antigen, a protein associated with myeloid suppressor cell activity in the tumour microenvironment. The Merck trial tested MK-4830 with or without Keytruda in 84 evaluable subjects with various cancers, mostly third-line or greater. University of Toronto’s Dr Lillian Siu told Esmo that there had been 11 remissions, nine of which were in the combo cohort. This seems modest, but five of these came in subjects who had progressed after earlier PD-(L)1 blockade. Jounce reckons it can catch up by dosing JTX-8064 higher, escalating faster, and more rapidly starting a combo with its in-house anti-PD-1, JTX-4014. A phase I trial is to start this year, and no other projects with this mechanism appear in the industry pipeline.
After this article was published Immune-Onc Therapeutics contacted Evaluate Vantage to point out that its anti-LILRB2/ILT4 MAb IO-108 was in IND-enabling studies.