MSD (Merck & Co) has secured a win for its anti-TL1A hopeful, tulisokibart, in painful skin condition, hidradenitis suppurativa (HS), while posting a loss for the drug in a rare lung disease.
During the company’s Q2 earnings call, MSD executives shared initial topline results from a primary analysis of two Phase II trials, which were evaluating tulisokibart in both hidradenitis suppurativa (HS) and systemic sclerosis-associated interstitial lung disease (SSc-ILD).
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In the HS trial (NCT06956235), the anti-TL1A therapy met both its primary and secondary endpoints, which looked at the percentage of patients achieving abscess and nodule clearance of more than 50%, as well as adverse events (AEs), measures of quality of life (QoL) and greater clearance, as per a ClinicalTrials.gov filing. Following this top-line update, the New Jersey-based pharma giant noted it would share further details from this trial at an upcoming medical conference.
On a less positive note, the drug failed to demonstrate a significant impact in a Phase II trial (NCT05270668), dubbed ATHENA-SSc-ILD, in SSc-ILD – leading MSD to discontinue the drug’s development in the condition. The pharma giant inherited this study from tulisokibart’s original developer, Prometheus Biosciences, which MSD acquired for $10.8bn back in 2023.
Anti-TL1A drug class catches big pharma’s eyes
While tulisokibart’s flop in SSc-ILD will be disappointing for MSD, the drug’s success in HS still puts it on course for potential future success as the drug class attracts the attention of several large pharma companies – including Roche, Teva and Sanofi.
With billions of dollars siphoned into securing deals for anti-TL1As, many companies are now hoping to determine if drugs in this class hold ‘pipeline-in-a-product’ potential, with development efforts spanning skin conditions, inflammatory bowel diseases and rheumatological indications.
Currently, tulisokibart has the broadest development programme for any anti-TL1A, which spans HS, ulcerative colitis (UC), Crohn’s disease, rheumatoid arthritis (RA), radiographic axial spondyloarthritis (r-axSpA) and psoriatic arthritis (PsA).
As per Phase III data debuted in June 2026, tulisokibart could hold significant potential in UC, with the drug having met its primary and key secondary endpoints in the condition.
In its Q2 earnings, MSD executives noted that they will also look into the combinatory potential of tulisokibart.
Tulisokibart’s clinical successes thus far will be welcome news for MSD, which is currently looking to stave off the financial impacts of cancer therapy Keytruda’s (pembrolizumab) patent expiry in 2028 by bolstering its commercial portfolio and pipeline.
Keytruda will leave a particularly large hole for MSD to fill due to the drug’s huge reach across the solid tumour treatment paradigm, which led it to become one of the best-selling drugs in the industry’s history. In 2025, Keytruda pulled in sales of $31.7bn.
