Rentosertib's six aging clocks point to a biomarker signal

This brief covers developments published between September 7 at 08:15 and September 8 at 08:15 in Dhaka. One fully documented study qualified in that window: Insilico Medicine reported results from a clinical-trial analysis that used six blood-protein aging clocks to examine its AI-designed lung drug rentosertib.

Rentosertib, also known as ISM001-055, is a small molecule designed to inhibit TNIK, a target Insilico selected through its AI drug-discovery work. The company developed the candidate for idiopathic pulmonary fibrosis, a progressive scarring disease of the lungs. The new analysis used samples collected during a Phase IIa trial, giving the trial an additional way to measure biological change. 1

The researchers measured 2,841 proteins in longitudinal blood samples from 42 trial participants. They then applied six proteomic aging clocks: ProtAge, ipfP3GPT, OrganAge's chronological-age and mortality variants, PAOPAC, and PAC. These models estimate biological age from protein patterns in blood. A lower estimate means that the protein pattern resembles the reference pattern of a younger group. The estimate describes a protein pattern associated with younger reference groups. Evidence about lifespan or slower aging requires clinical follow-up. 1

Insilico's composite figure compares predicted biological-age changes across six clocks, treatment groups, and study weeks. 1

Insilico reported that all six clocks showed a reduction in predicted biological age among treated participants compared with placebo. The largest reported signal appeared at Week 4 in the 30 mg twice-daily group, where the clocks indicated roughly three to four years of predicted age reversal; one clock reached as much as six years. These are model outputs from a small clinical-trial cohort, so the useful result is the consistency across models and the specific pattern that later trials can test. 1

The study also reported dose-dependent changes in forced vital capacity, a measure of lung function. The strongest lung-function dose and the strongest predicted-age signal were different, according to Insilico's announcement. That separation gives the researchers a way to ask whether the protein signal tracks a broader biological response alongside respiratory improvement and beyond one clinical measurement. The answer will require the trial's full analysis and replication in other groups. 1

What to watch: The next useful checkpoint is a study in healthy volunteers, which Michael Levitt identified as the experiment needed to separate a change linked to treated lung disease from a broader aging effect. Later rentosertib trials can also show whether the proteomic signal appears again alongside patient outcomes. 1

Watch for the same six-clock pattern in a larger or independent cohort, and for a trial design that includes healthy volunteers or another control able to separate lung-disease improvement from a general change in biological-age markers. The paper, Integration of proteomic aging clocks in a phase 2a clinical trial supports simultaneous geroprotective assessment, is published in Nature Biotechnology under DOI 10.1038/s41587-026-03286-y. 1