In ~2.5 years, MASH has gone from its first FDA approval to a ~$1.5B annualized drug launch, $8B+ in upfront FGF21 acquisitions and a crowded 500+ asset landscape. But what's fascinating is the commercial / clinical split is happening much earlier than usual.
By all accounts, the commercial market is barely penetrated. Madrigal (while biased) estimates 1% penetration - the prescribing and diagnostic infrastructure needed to identify the ~410K untreated patients in the US is in its infancy.
Against this backdrop, we historically used to see a number of fast followers with near-identical trial designs and target patient populations, even in mid-stage development.
Instead, even later-stage R&D is already planning for a more fragmented, multi-drug treatment environment canonically associated with more mature markets. Many trials are segmented by fibrosis stage, metabolic comorbidities and, importantly, response to emerging frontline treatments, including GLP1s (Wegovy was approved in MASH in August 2025).
Planning for future treatment sequencing has always been part of the playbook, but the degree of competition in every corner of drug development these days has pushed forward the need to have a differentiated patient angle. Every shift in the SOC creates a new patient phenotype that did not exist before.
In this case, GLP-1 exposed MASH patients will differ histologically from the untreated population and the bet is that the broad reach of GLP1s will flip these ratios over time (Novo indicated 1/3 of patients in efruxifermin's Ph2 study were already on GLP1s), as it may be a more natural discovery point for undiagnosed patients.
And that means the next drug will need different comparators, patient selection criteria and, potentially, endpoints to answer emerging treatment questions, like: what additional benefit should a liver-directed drug deliver? When do you add it?
An asset's competitive position isn't fixed the moment it enters clinical development, so staying nimble to skate where the puck is going is critical.
Going back to MASH, we pulled together an interactive landscape covering mechanisms, fibrosis stages, efficacy, deals, China and upcoming readouts:
sleuthinsights.com/analysis/…
Some takeaways from that work:
• F4 is the next expansion opportunity - current approvals cover F2/F3, but ~250K additional US patients have compensated cirrhosis
• The next 12 months are packed with catalysts, including Inventiva's pivotal lanifibranor readout, Phase 3 data from Novo and Roche's FGF21s, and the expected Rezdiffra cirrhosis outcomes readout
• GLP1s haven't yet boxed out liver-directed drugs. Rezdiffra is still adding ~6-7K net patients per quarter despite Wegovy's entry
I've included a snapshot below but it's definitely worth playing with yourself!
For those working in MASH, what are we missing? Particularly interested in which patient segments and treatment combinations you think will matter most over the next few years.