Merck’s $10.8B Prometheus deal delivers another win—plus a Phase 2b miss

News Business Merck’s $10.8B Prometheus deal delivers another win—plus a Phase 2b miss August 4, 2026 | 3 min read | Gabrielle Masson Twitter LinkedIn Facebook Email Print The anti-TL1A antibody from Merck’s 2023 Prometheus buy delivered positive mid-stage results in a skin condition but failed in a certain type of lung disease, the Big Pharma revealed alongside second-quarter earnings. Merck has recorded a loss and a win for the experimental anti-TL1A antibody it picked up in its nearly $11 billion immunology buyout of Prometheus Biosciences a few years back.The asset, a monoclonal antibody known as tulisokibart, failed to meet the main goal of a Phase 2 trial for patients with systemic sclerosis-associated interstitial lung disease (SSC ILD), according to Merck’s second-quarter earnings release shared Tuesday. The miss has prompted the New Jersey–based pharma to discontinue the study.Merck didn’t share data behind the fail but said no new safety concerns were identified.

The study enrolled 154 patients and lists three safety measures and one efficacy goal as primary endpoints. The Big Pharma also reported a win for tulisokibart in a skin condition called hidradenitis suppurativa (HS), announcing that the Phase 2b trial met its primary and key secondary endpoints. Merck was mum on the details but said it would share the full results at an upcoming medical conference.

The study enrolled 147 patients and measured the percentage of participants with an over 50% reduction in skin abscesses and inflammatory nodules.Merck picked up tulisokibart in 2023 when it acquired Prometheus for $10.8 billion. Also known as MK-7240, tulisokibart was the centerpiece of the deal, with its main promise expected as treatment for of ulcerative colitis (UC) and Crohn’s disease. Inflammatory bowel disease Merck posts ‘encouraging’ Phase 3 ulcerative colitis data but Roche challenge looms Given its intravenous route of administration, Merck’s tulisokibart will likely “need to be meaningfully improved” over Roche’s afimkibart, which can be given subcutaneously, BMO Capital Markets analysts said.

Both assets are being tested for ulcerative colitis. June 23, 2026 · 2 min read · Tristan Manalac Read more Earlier this summer, Merck reported a Phase 3 victory for tulisokibart in UC, sharing that the anti-TL1A antibody helped patients achieve clinical remission, without revealing any data. Given the lack of information, analysts remained cautious about the asset’s prospects, also citing potential competitive overhangs.

For example, Roche picked up the anti-TL1A antibody afimkibart in its $7.1 billion Telavant acquisition in 2023.“With Merck’s tulisokibart administered by IV and Roche’s afimkibart administered subcutaneously in the induction setting, tulisokibart’s efficacy would likely need to be meaningfully improved vs. afimkibart to be competitive and support strong preferential uptake if approved,” BMO analysts wrote in June.Merck is also developing a subcutaneous formulation of tulisokibart for maintenance treatment, which BMO noted “could help lessen such headwinds to uptake.”“We look forward to the upcoming readout of the larger induction and maintenance study, which, together with the induction-only study, would form the basis of a regulatory filing and will be presented at an upcoming scientific congress,” Merck R&D head Dean Li said on an Aug. 4 investor call.

He added that the UC late-stage results “reinforce the potential of targeting TL1A to help address immunofibrosis, a key driver of disease progression across multiple immune-mediated inflammatory conditions.”Li framed the Phase 2 studies as an exploration of the anti-TL1A hypothesis, citing a broad development program across radiographic axial spondyloarthritis, psoriatic arthritis and rheumatoid arthritis.“The positive readout for HS gives us more confidence in the derm possibilities for this drug, and so that’s where we’re looking at,” Li said on the call’s Q&A portion. When pressed on the failure in SSC ILD, he said, “I would just step back. I don’t know any anti-cytokine that has worked.

So, this was a bold move to move that forward. It’s a challenging and refractory disease.” Approvals Merck dives into cholesterol with first FDA approval for oral PCSK9 inhibitor Merck’s once-daily pill is the first oral PCSK9 inhibitor to hit the market for high cholesterol, beating AstraZeneca in the race to develop more accessible treatment options. July 16, 2026 · 2 min read · Gabrielle Masson Read more A narrow beat Overall, it was a clean quarter with key launches demonstrating traction, according to a Tuesday note from BMO analysts.Merck reported $16.6 billion in sales, up from the expected consensus estimate of $16.37 billion.The pharma also narrowed and raised its sales guidance for the 2026 fiscal year to a midpoint of $66.8 billion, up slightly from $66.4 billion.

Earnings per share (EPS) estimates narrowed to $2.66–$2.76, taking into account a hefty negative impact related to the $6.7 billion Terns buyout that closed in the second quarter. The pharma had previously expected its 2026 EPS to range from $5.04 to $5.16.Merck’s beats stemmed from faster-than-expected conversions to Keytruda Qlex, the subcutaneous formulation of the blockbuster cancer therapy traditionally delivered intravenously. A 20% beat over consensus estimates for oncology product Welireg gave Merck an additional boost.

Chronic obstructive pulmonary disease med Ohtuvayre also served as “a bright spot,” up 19%, according to Guggenheim analysts. Meanwhile, newly approved Enflonsia for RSV fell short of consensus estimates by 84%, but BMO analysts said the launch was still early and “initial revenue lumpiness is expected.” Mergers & acquisitions Merck To Buy Terns, ‘Unprecedented’ Leukemia Drug for $6.7B as Keytruda Cliff Looms Merck’s acquisition of Terns Pharmaceuticals follows other big-ticket purchases, including of Verona Pharma and Cidara Therapeutics, as the pharma prepares for the impending expiration of its blockbuster’s patents. March 25, 2026 · 3 min read · Tristan Manalac Read more Twitter LinkedIn Facebook Email Print Earnings Merck & Co.

Gabrielle Masson Gabrielle is a senior editor at BioSpace. You can reach her at gabrielle.masson@biospace.com.