Four-month oral administration of PAI-1 inhibitor makes healthy elderly people 2-3 years younger

In a semifinal clinical trial (specified clinical trial) for "XPRIZE Healthspan," an international competition for longevity, Professor Toshio Miyata of Tohoku University Graduate School of Medicine and his collaborators at Hiroshima University, Tokai University and Renascience Inc., have confirmed anti-aging effects of a PAI-1 inhibitor, TM 5614, at genetic, epigenetic (genetic modification), protein and cellular levels in relatively healthy elderly humans. A four-month oral administration of TM 5614 resulted in an average of 2- to 3-year decrease in the biological age. The key to their success was a new approach that broadly aimed at improving the aged environment to recover homeostasis.

If selected as a finalist in August, the team will conduct a large-scale international clinical trial (100 or more subjects) in collaboration with Japan, the United States, Saudi Arabia and Taiwan.

In developed countries with hyper-aging populations, a gap of about 10 years exists between average life expectancy and healthy life expectancy, which is considered a major issue to be solved.

Reducing the burdens of age-related diseases, such as cancer, atherosclerosis, chronic obstructive pulmonary disease, diabetes, chronic kidney disease, cerebrovascular disease, dementia, sarcopenia and osteoporosis, should contribute to extension of healthy life expectancy.

PAI-1 molecules are known to be overexpressed in senescent cells and cancer cells, which avoids removal of these cells by the immune system. The efficacy of TM5614 (a PAI-1 inhibitor developed by Miyata) against cancer is currently evaluated in multiple clinical trials (chronic myeloid leukemia, malignant melanoma, angiosarcoma, non-small cell lung cancer and pancreatic cancer), including phase III trials, and has been demonstrated to some extent.

The research team was selected as a semifinalist (top 40) for the XPRIZE Healthspan in May 2025 and has been conducting a semifinal clinical trial since August 2025. Semifinalists are required to conduct a short-term (4 to 8 weeks), small-scale (5 to 20 subjects) clinical trial as a semifinal clinical trial to demonstrate the feasibility of the final 4-year clinical trial.

At the semifinal trial, the team conducted an open-label trial in which TM5614 was administered over four months to 20 relatively healthy subjects aged 50 to 75 with stably controlled age-related diseases (hypertension, type 2 diabetes, chronic kidney disease and hyperlipidemia). Nineteen patients (mean age 60.4 ± 5.6 years; 13 males, 6 females) who could take both the pre- and post-administration examinations were included in the efficacy evaluation, and 20 patients who received the TM5614 administration were included in the safety evaluation.

Regarding safety, there was one adverse event (mild liver function abnormality) in which a causal relationship with TM5614 could not be ruled out. However, no other serious adverse events, including bleeding events, were observed. In terms of efficacy, findings suggestive of systemic anti-aging actions were obtained, despite the relatively short administration period of four months.

First, DNA methylation (epigenetic modification) was analyzed to estimate the biological age. The estimated biological ages of the subjects analyzed by the Horvath method and the PC-Horvath method were 61.7 and 58.0 years, respectively, which were close to their actual ages (average 60.4 years).

After 4 months of TM5614 administration, their estimated biological ages were significantly decreased to 58.3 years (decreased in 15 of 19 patients) and 56.1 years (decreased in 18 of 19 patients) when analyzed by the Horvath method and the PC-Horvath method, respectively. A significant decrease was also observed in senescence-associated microRNAs (SA-miRNAs), indicating a reduction in senescence-inducing gene expression control.

An analysis of 7,596 plasma proteins was conducted by SomaScan assay with aptamers (nucleic acid antibodies). According to the analysis, 356 (4.7%) and 199 (2.6%) proteins significantly increased and decreased, respectively. Most of the 19 subjects shared similar changes, and multiple proteins were significantly altered.

Changes were observed in multiple proteins associated with anti-aging effects, suggesting that TM5614 may be involved in enhancement of various anti-aging actions, including anti-inflammatory effects, macrophage functions, bone and muscle tissue formation, cognitive and neurophysiological functions, antithrombotic effects, lipid metabolism and endoplasmic reticulum (ER) stress.

Fractionation of immune cells in peripheral blood by surface markers revealed that NK cells, which are known to increase with age, decreased in 14 of 19 subjects, and dendritic cells increased in 12 of 19 subjects. The findings suggest an enhancement of immune surveillance against senescent cells.

After the administration of TM5614, hematopoietic stem/progenitor cells in peripheral blood, which are known to decrease with age, were significantly increased in 15 of 19 subjects. In particular, multi-lymphoid progenitors (MLPs), considered to be involved in age-related decrease in lymphocyte production, were increased in 15 of 19 subjects.

Moreover, a comprehensive analysis of gene expression in hematopoietic stem/progenitor cells revealed that expression levels of gene sets defining the differentiation stages of these cells were significantly changed, suggesting an overall rejuvenation of gene expression. A decreasing trend was observed in serum oxidative stress markers (decreased in 14 of 19 subjects).

Carboxymethyl lysine (CML), an advanced glycation end product (AGE) produced by glycation of proteins and serving as an indicator of aging, was also decreased in 16 of 19 subjects. Despite the short-term administration, the study confirmed anti-aging effects in a wide range of organs, including those involved in immunity, metabolism, bones and muscles, cognition and neurophysiology, anti-oxidation and hematopoietic stem cells. Whether these molecular-level changes actually contribute to anti-aging effects in various organs and ultimately to the extension of healthy life expectancy needs to be further verified in future studies. The team expects to verify these if selected as a finalist (top 10)

Conventional drug development assumes to deal with a single disease, a single target and clear endpoints. Meanwhile, "senescence" is an extension of aging and is not considered a "disease." Because aging is a continuous process and greatly varies among individuals, it is difficult to develop drugs by viewing "senescence" as a single disease.

Various challenges are faced upon commercialization of anti-aging drugs, including those related to regulations, clinical trial design, insurance reimbursement systems and business models.

In recent years, novel aging interventions (therapies) that differ from classical aging interventions (e.g., diet, exercise, sleep and supplements) have been proposed. They are based on new mechanisms such as epigenetic reprogramming (cell rejuvenation) and senolytics (removal of senescent cells). Some of them are beginning to be evaluated in clinical trials.

RS5614 is an oral medication intended for senolytics. Senescence is a state in which a wide range of biological homeostasis is disrupted, including epigenetic information, metabolism, inflammation and stem cell function. For intervening in senescence, it is essential to adopt a perspective focusing not on "improving a specific pathological condition" but on "broadly improving the aged environment and re-establishing the balance of the entire body." When senescent cells evade elimination by the immune system and accumulate in the body, they continuously release inflammatory cytokines and chemokines, known as senescence-associated secreted phenotype, and cause chronic inflammation in the surrounding healthy cells and tissues.

PAI-1 inhibitors are drug candidates that can intervene across multiple pathways in an integrated manner to rebuild the disrupted homeostasis of the entire body. They have the potential to improve the aged environment, eliminate senescent cells, rejuvenate biological age and prevent and treat various aging-related diseases.