Lilly paid up to $2.3 billion for Ajax Therapeutics. Phase 1 data at the European Hematology Association meeting this week just showed what that money bought.
AJ1-11095, the lead asset from Lilly’s April acquisition, hit a 70% SVR35 rate in Phase 1 trial AJX-101. All 23 patients enrolled had already failed a Type I JAK inhibitor; historical SVR35 rates in that same post-JAK setting run 0% to 32%.
The mechanism is the bet. AJ1-11095 targets the Type II conformation of JAK2, where approved drugs like Jakafi bind Type I. Type I inhibitors don’t typically move that mutation needle; AJ1-11095 appears to. Variant allele frequency dropped in 21 of 23 patients, with 35% seeing a 50% or greater reduction by week 24.
At EHA 2026, Incyte disclosed updated data on INCA033989, its CALR-targeted antibody. Best SVR35 was 39%; Week 24 rate was 27% across 62 patients. Analysts had estimated peak-sales potential for INCA033989 at $1.9 billion. The comparison with Lilly isn’t clean, given different populations and mechanisms, but Lilly’s 70% number is what the market sees.
Here’s the read-across. INCA033989 covers roughly one-fourth to one-third of MF patients — those with CALR mutations. AJ1-11095 showed VAF reductions across JAK2, MPL, and CALR mutations alike, with Lilly finding no excluded subtype in the early data. A pan-subtype drug competing across the full MF population is a different competitive threat to Jakafi’s franchise than a mutation-selective antibody.
Lilly plans to declare a dose and start phase 3 in second-line MF as quickly as possible. Van Naarden: “We are not done.”
Diana Kowalski