Gilead Sciences will acquire U.K.-based startup MiroBio, which is developing antibody drugs for autoimmune disorders, in a $405 million deal announced Thursday.

MiroBio sprouted from a University of Oxford research laboratory run by professors Simon Davis and Richard Cornall. Its approach focuses on checkpoint receptors, proteins that help to regulate the immune system.

Blocking these proteins has proven effective in treating cancer, unleashing the immune system to attack malignant cells. But companies like MiroBio are exploring how they can be targeted to tamp down damaging immune system overreactions in inflammatory diseases.

Existing autoimmune disease drugs generally reduce the overall amount of inflammation in the body. By comparison, MiroBio aims to use antibodies to selectively stimulate the immune system’s “brakes,” finding the correct checkpoint receptor to block overactive immune cells.

Striking this balance is tricky, but more precise treatments could help people with autoimmune diseases without leaving them vulnerable to infections.

MiroBio’s most advanced experimental antibody, dubbed MB272, targets T, B and dendritic cells to rein in inflammatory immune responses. MB272 entered Phase 1 clinical trials this week as the deal with Gilead was announced.

The company’s other drug, a PD-1 agonist, is in preclinical testing.

Backed by Samsara BioCapital and Oxford Sciences Enterprises, MiroBio was spun out of Oxford in 2019. Cofounder Cornall had previously worked at Stanford University with Samsara’s founder Srini Akkaraju, who connected Cornall with Eliot Charles. An alum of Genentech and Amgen who had recently landed in the U.K., Charles is now chair of MiroBio’s board of directors.

MiroBio raised $33 million in a Series A round in 2019, and added another $97 million in Series B funding in June.

According to Charles, MiroBio did not set out seeking an acquisition. But he said the startup had received “an awful lot of interest” since 2019, and began talking to Gilead more seriously late last year

“Market conditions were bad, but we managed to raise more than $100 million and that’s a testament to the people,” he said.

MiroBio’s preclinical data attracted Gilead, which plans to generate additional drugs targeting immune receptors from MiroBio’s research platform. The acquisition expands Gilead’s presence in anti-inflammatory disease, a corner of their research alongside a longstanding focus on HIV and hepatitis C.

“We perceive [the deal] more as a continuation rather than a shift back to inflammation and consistent with their overall business development strategy to do smaller-sized deals,” said Salim Syed, a biotech analyst at Mizuho Securities.

Gilead has eyed a larger business in anti-inflammatory drugs with its substantial $5 billion investment in Belgian biotech Galapagos. But in 2020, the Food and Drug Administration rejected filgotinib, one of Galapagos’ most important drugs.

Immune diseases have drawn significant investment from other large pharmaceutical companies, such as Eli Lilly and Merck & Co., who are interested in new, more targeted anti-inflammatory approaches. In 2021, Merck acquired Pandion Therapeutics in a $1.9 billion deal. At the time, Pandion had reported positive results from a Phase 1 clinical trial testing a treatment for ulcerative colitis and lupus.

After a dearth of dealmaking in recent years, acquisitions are on the upswing in the pharma industry. The second quarter was busy, with 14 biotech buyouts worth $50 million or more, according to data from BioPharma Dive. Just earlier this week, Amgen bought biotech company ChemoCentryx for nearly $4 billion.