MASH stands for “metabolic dysfunction-associated steatohepatitis”, a disease characterised by the buildup of fat deposits in the liver, causing inflammation 1. Globally, 38% of adults suffered from MASH between 2016 and 2019 2. This number is projected to reach over 55% in 2040, making MASH a substantial market.
Historically, MASH was a risky therapeutic area with a high R&D failure rate. For years, MASH patients were offered nothing other than diet and exercise advice 3. March 2024 marked a key milestone for the disease area with the first-ever approval of a MASH medication, Rezdiffra, produced by Madrigal Pharmaceuticals 4. Rezdiffra is a daily oral pill, indicated for MASH with moderate to advanced fibrosis. The monopoly didn’t last long. In August 2025, Novo Nordisk’s Wegovy was approved for the same indication 5.
Nevertheless, there are still substantial gaps in the market to be addressed. These include medications for more severe MASH stages, with improved tolerability/efficacy, and with additional cardiometabolic benefits (due to the substantial overlap with other metabolic diseases) 3, 6.
Prompted by these initial approvals, Big Pharmas have been racing to enter the MASH market through major acquisitions. Some examples include GSK’s US$2B acquisition of Boston Pharmaceuticals (July 2025), Roche’s US$3.5B acquisition of 89bio (Sep 2025), and Novo Nordisk’s $5.2B acquisition of Akero Therapeutics (Dec 2025) 3.
All of these acquisitions were made to acquire a MASH asset that could be used in combination with Big Pharma’s own drug – this is the combination therapy strategy, where two or more different medications are used together in a single treatment regimen 3. This could improve patient outcomes when the two drugs work synergistically 7.
GSK’s acquisition gives it access to Boston Pharmaceuticals’ efimosfermin, currently in phase III clinical trials for MASH 8. The company plans to run trials combining this drug with its own GSK’990, which uses another mode of action to target MASH 9.
Similarly, Roche’s acquisition gives it access to 89bio’s pegozafermin, also in phase III trial for MASH, which could be combined with Roche’s existing incretin-based assets 10.
Despite having huge potential, combination therapies are often difficult to design due to the cross-company dynamics and legal implications involved, along with technical challenges 11.
In theory, a company is allowed to conduct clinical trials to test a combined therapy in which one drug is a patented drug from another company. This is due to a provision known as ‘research exemption’, which exists in the UK, US, and EU 12.
However, the company will need permission from the patent holder to market the new drug combination. Any commercial activities involving the branded drug without a license will be infringing patent laws. Moreover, the large supply of drugs needed for the trial necessitates collaboration with the manufacturer. Thus, in practice, companies often form some kind of partnership/agreement to co-develop a combination therapy.
For instance, in 2021, Gilead and MSD entered a collaboration to test a combined therapy involving Gilead’s Trodelvy and MSD’s Keytruda for triple-negative breast cancer 13. As part of the agreement, Gilead will sponsor a phase III global clinical trial for the combination, while MSD agreed to supply Keytruda for the trial. The trial was a success, demonstrating significant improvement in patient survival compared to standard treatment 14.
In another case, in 2017, AstraZeneca and MSD entered a strategic collaboration to co-develop and co-commercialise AstraZeneca’s Lynparza for various cancers 15. The two companies would jointly develop and commercialise Lynparza as both a monotherapy and in combination with other medicines, including MSD’s Keytruda.
If successful, the partners will likely agree on a profit-sharing structure for selling the combined therapy.
Most combination therapy agreements are between large and established pharmaceutical companies. In the cases of MASH, rather than entering a collaborative agreement, large pharmaceuticals straight up purchase the company with the MASH asset it wants to use.
This makes strategic sense. When a drug belongs to a large pharmaceutical company, a straight-up purchase of the company is expensive and unnecessary. The cost of profit-sharing through a collaborative agreement is more justifiable. In the case of MASH, where a smaller biotech company owns the drug, it is easier to acquire the partner than to draw up a collaborative agreement.
Thus, the recent wave of Big Pharma’s bet on MASH medication was an interesting case study, showing how patent protection laws could have implications for a company’s strategic partnership decision.