Astellas Pharma has become the latest company to pull back from a potential treatment for Sjögren’s syndrome, an autoimmune disease that still lacks any dedicated medicines.
The Japanese drugmaker has terminated a phase 1 study of ASP5502, a small molecule inhibitor of a protein called “stimulator of interferon genes” or STING. The cancellation “was a business decision and not related to safety or efficacy observed in the study,” an Astellas spokesperson told Fierce Biotech.
The study, which enrolled 116 people, will complete its current cohort, the spokesperson added, while the future of ASP5502 “will be disclosed at the appropriate time.”
The trial was designed in three parts. Part one was meant to test a single oral dose of the ASP5502 tablet in healthy volunteers, with part two then progressing to daily treatment for two weeks, also with healthy volunteers. Part three would then follow up with daily doses of the molecule for four weeks in patients with Sjögren’s syndrome.
At the time of publication, the Astellas spokesperson had not responded to follow-up questions from Fierce about which cohort the study had reached at the time of termination.
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Sjögren’s syndrome is an autoimmune disease where the patient’s immune system attacks the tear and salivary glands, leading to dry eyes and mouth. Those primary symptoms can also be accompanied by issues affecting the joints, nerves, lungs and other organs. Symptoms are typically managed with anti-inflammatory medications, but the FDA has never approved a drug specifically designed to treat Sjögren’s.
Astellas’ trial termination follows other Big Pharmas that have ditched assets in the indication. At the beginning of 2025, Novartis gave up on an anti-CD40 antibody, iscalimab, that had shown some promise at treating Sjögren’s. The Swiss pharma is still pursuing a different antibody, ianalumab, for Sjögren’s and other autoimmune diseases.
Ianalumab scored a breakthrough therapy designation from the FDA for Sjögren’s in January.
Bristol Myers Squibb, Sanofi and Kiniksa Pharmaceuticals have all similarly stepped away from anti-CD40 antibodies for Sjögren’s in recent years.
Astellas’ ASP5502 is one of the few molecules in the clinic targeting the STING pathway, which plays a key role in promoting inflammation. Other STING assets have also proven unsuccessful, with none surviving to phase 3 trials.
The Sjögren’s setback comes mere weeks after Astellas nixed a $1.6 billion T-cell engager partnership with CytomX Therapeutics.
