Eli Lilly bought a Phase 1 biotech for $2.3 billion this morning.
Yes, you read that right. Phase 1.
Ajax Therapeutics dosed its first patient in October 2024. Lilly announced the acquisition this week, valued at up to $2.3 billion, with proof-of-concept data still expected later in 2026.
So what’s actually being bought here?
The asset is AJ1-11095, a Type II JAK2 inhibitor – and its the “Type II” part that is actually what’s important.
Every approved JAK inhibitor on the market today, ruxolitinib included, binds JAK2 in its active conformation. Ajax’s compound binds the inactive conformation.
Okay…why does that matter?
Because most myelofibrosis patients eventually fail Type I inhibitors. They get spleen reduction and symptom relief, but the underlying disease keeps moving. In preclinical models, AJ1-11095 reversed marrow fibrosis, reduced mutant allele burden, and stayed effective against MPN cells that had become resistant to chronic Type I exposure.
These are things ruxolitinib couldn’t do.
Ajax Therapeutics funding trajectory
Earlier rounds
2019–2023
Series C
Goldman, Lilly, Vivo
Lilly acquisition
Apr 2026
From ~$145M raised to $2.3B exit, ~18 months after first patient dosed
Two things made this exit happen pre-data.
First, the team has a track record.
Ajax’s leadership and Schrödinger collaborators previously worked together on a TYK2 inhibitor at Nimbus Therapeutics. Takeda bought that program for $4 billion in 2022. So, yeah…this is the same team with a very similar playbook – Lilly trusted that they could do it again.
Second, Lilly was already in the cap table – that always helps.
They participated in the May 2024 Series C alongside Goldman Sachs, Vivo Capital, RA Capital, and Point72. Insider deals like this don’t happen randomly. Lilly had a year of close access, watched the IND go through, watched dosing start, and decided to convert their option before anyone else could.
This is also the second-largest pre-POC acquisition I can remember in recent biotech history. The implication for early-stage hematology programs with differentiated mechanisms is that big pharma is willing to pay before they see human data, when the preclinical story is good enough and the team has run the play before.
For founders building precision oncology platforms, take the meeting when Lilly wants to invest.
The Biotech Voyager
Early-stage biotech signals, personalized.
The signals that matter to you — contextualized and written directly to you — so you cut through the noise and immediately understand why it matters.
