Crohn's and Colitis: The $18 Billion Bet on One New Drug Target

The Most Important Number in IBD Isn't a Trial Count

Inflammatory bowel disease (IBD) — the umbrella term for ulcerative colitis and Crohn's disease — has 553 actively recruiting trials on ClinicalTrials.gov, 46 of them in Phase 3. Those are healthy numbers for a chronic-disease category. But they aren't the number that matters most.

The number that matters is $18 billion. That is roughly what Merck, Roche and Sanofi committed between April and October 2023 to acquire or license antibodies against a single new target: TL1A (TNF-like ligand 1A). Three deals, one mechanism, in roughly six months. It is the clearest signal in IBD competitive intelligence right now — and it tells you where the next standard of care is expected to come from.

TL1A is a protein that, according to the companies developing against it, amplifies inflammation and drives the fibrosis (tissue scarring) that makes IBD progressive and hard to treat. The thesis behind every one of these deals is the same: an anti-TL1A antibody might do something the current drugs don't — calm inflammation and slow scarring at once, in both ulcerative colitis and Crohn's, with a single mechanism.

The TL1A Feeding Frenzy: $18 Billion in Six Months

Three deals built the TL1A field. Two were outright acquisitions; one was a co-development partnership. Together they pulled the target from clinical-stage biotech into the hands of three of the biggest names in immunology.

Merck moved first, acquiring Prometheus Biosciences for approximately $10.8 billion in a deal announced in April 2023 — a roughly 75% premium that valued the company almost entirely on its lead anti-TL1A antibody, tulisokibart (STAT, April 2023). Six months later, Roche paid $7.1 billion up front (plus a $150 million milestone) to acquire Telavant — a vehicle Roivant and Pfizer had built around RVT-3101 — securing US and Japan rights to the antibody and an option on a next-generation p40/TL1A bispecific (BioPharma Dive, October 2023). Weeks earlier, Sanofi and Teva had agreed to co-develop and co-commercialize duvakitug, with Teva taking $500 million up front, up to $1 billion in milestones, and a 50/50 split of costs and profits.

Who Is Running TL1A Phase 3 Right Now

All three programs are past the validation stage and into pivotal trials. As of today, the three TL1A antibodies account for 11 currently recruiting Phase 3 trials across ulcerative colitis and Crohn's disease — nearly a quarter of all 46 Phase 3 IBD trials recruiting on ClinicalTrials.gov.

Roche has converted its acquisition into the broadest Phase 3 footprint: all five of its currently recruiting IBD trials are RVT-3101 studies. Sanofi's four recruiting Phase 3 trials are all duvakitug, now run under Sanofi as the Phase 3 lead after Teva ran the earlier studies. Merck's two recruiting Phase 3 tulisokibart trials are a more concentrated bet — fewer trials, but on the asset that triggered the whole frenzy.

The Market They're Buying Into Is Already Crowded

Here is the tension in the TL1A thesis: the IBD market these antibodies are racing toward is not empty. It has been one of the most active approval categories in all of medicine over the last three years. An anti-TL1A drug that reaches the market will arrive into a field where several mechanisms already work and several launched recently.

That is just the recent wave. Behind it sits an established backbone: anti-TNF biologics (the legacy standard), the anti-integrin vedolizumab (Takeda's Entyvio), the IL-12/23 inhibitor ustekinumab (now facing a wall of biosimilars), and the oral JAK inhibitor upadacitinib (AbbVie's Rinvoq), approved across IBD. The interleukin-23 class in particular has become the center of gravity, with three IL-23 antibodies winning fresh IBD indications in 2024–2025 alone (MedCentral, 2025; AJMC).

Who Has the Most Active IBD Trials

Volume and pivotal-stage concentration tell two different stories. The established franchises lead on sheer number of recruiting trials; the TL1A acquirers show up as smaller but almost entirely Phase 3.

Industry lead sponsors only; academic and hospital sponsors excluded. Eli Lilly's figure excludes one additional trial registered under its Morphic Therapeutic subsidiary; Johnson & Johnson runs several more under regional Janssen affiliates. Recruiting trials as of May 31, 2026.

Read the two columns together and the strategy split is obvious. Takeda (13 recruiting, defending its Entyvio franchise) and AbbVie (13 recruiting, behind Skyrizi and Rinvoq) lead on breadth. But Roche and Johnson & Johnson run pure Phase 3 books — every recruiting trial is pivotal-stage — and Roche's entire footprint is the single TL1A asset it bought. Concentration like that is a tell: it's what a company looks like when it has stopped exploring and is racing to register one bet.

A note on attribution: ClinicalTrials.gov lists the registered lead sponsor, which lags ownership. Some tulisokibart trials still appear under "Prometheus Biosciences, a subsidiary of Merck," and duvakitug's earlier studies sit under Teva — so the effective footprints of Merck and Sanofi are slightly larger than the lead-sponsor counts above suggest.

What to Watch Next

• The TL1A Phase 3 readouts are the main event. Eleven recruiting Phase 3 trials across three sponsors will start reporting over the next few years. The first strong registrational data validates the $18 billion and resets the IBD standard of care; a miss reopens questions about the whole class — and about the deals made on the assumption it would work.
• Fibrosis is the differentiator to watch for. The mechanistic pitch for TL1A is that it touches both inflammation and scarring. If a Phase 3 program can show a structural or stricture benefit that IL-23 inhibitors don't deliver, that is the claim that justifies the premium. Remission rates alone won't separate it from a crowded field.
• Pfizer isn't out of TL1A. As part of the Telavant deal, Roche took an option on a next-generation p40/TL1A bispecific that originated with Pfizer (BioPharma Dive, 2023). Combination and bispecific approaches that pair TL1A with IL-23 blockade are the likely second wave — worth tracking even though none are in Phase 3 yet.
• Biosimilars are reshaping the economics underneath all of this. Ustekinumab (Stelara) biosimilars won a wave of FDA approvals across 2024–2025, and the new IL-23 antibodies are partly a response to that erosion. TL1A drugs will be priced and positioned against a backdrop of cheapening incumbents — a commercial pressure that doesn't show up in trial data but will shape every launch decision.
• Takeda's franchise defense. With six recruiting Phase 3 trials and the most active overall pipeline, Takeda is the incumbent with the most to lose if TL1A becomes a new backbone. Watch whether its activity stays defensive (lifecycle work around vedolizumab) or moves toward a new mechanism of its own.