An experimental drug being developed for a serious lung disease has shown an unexpected side effect in early trials: it may also slow biological ageing. Researchers from Insilico Medicine, working with institutions including Harvard Medical School and Stanford University, found that patients taking the drug rentosertib displayed blood protein changes suggesting they were biologically several years younger after treatment, a finding the study's lead author described as a welcome "bonus" alongside its intended disease-fighting effects.

Rentosertib, an AI-discovered drug, is primarily being developed to treat idiopathic pulmonary fibrosis, a disease that causes lung scarring. In the study, published in Nature Biotechnology and presented at a conference in Paris, patients appeared on average three to four years younger, with one case showing a six-year difference, across six different ageing tests, with the strongest effect seen after four weeks at the higher dose tested. However, the trial involved only 42 patients over 12 weeks, and researchers cautioned that the lung disease itself may have influenced the same proteins used to measure ageing, meaning the results do not yet prove the drug slows ageing or extends life; side effects were described as "manageable".