Genflow Biosciences announces that its SLAB trial, conducted in 24 beagles over ten years old, has reached its primary endpoint: a reduction in estimated biological age measured by an epigenetic clock. Full results will be presented in October. The finding is of interest for what it may reveal about the mechanisms of aging, although it does not yet demonstrate that the animals have rejuvenated or that they will live longer.
Longevity research has just added a result that deserves attention for a specific reason: a genetic intervention targeting one of the cellular mechanisms linked to aging has produced a measurable change in an epigenetic marker of age in older dogs.
Genflow Biosciences has announced that its SLAB study —Sarcopenia and Longevity in Aged Beagles— has reached its primary endpoint. The trial included 24 beagles over ten years old, randomly assigned under blinded conditions to four groups: two cohorts that received different doses of plasmid DNA with SIRT6, a group treated with a single dose via an AAV8 vector, and a control group that received saline solution.
The primary endpoint was to determine whether the intervention modified biological age estimated using the GRIM methylation clock, a clock based on DNA methylation patterns. According to the company, the treated animals showed a signal of reduced biological age compared with the control group. It also reports improvements in various functional and observational variables.
There is an important detail in this news: Genflow has not yet published the full dataset. The company has announced that it will present the detailed results, including mechanistic analyses and methylation and muscle data, at the Animal Longevity Summit in Toronto on 1 and 2 October 2026.
SIRT6, a protein with a scientific history behind it
The choice of SIRT6 does not respond to a recent hypothesis. This sirtuin has been at the center of research related to aging, DNA repair, metabolism, and genomic stability for years.
SIRT6 is an NAD+-dependent enzyme that participates in different cellular maintenance mechanisms, including the repair of DNA double-strand breaks, chromatin regulation, metabolism, and certain inflammatory responses. Animal models have provided some of the most interesting evidence.
In 2012, a paper published in Nature observed that male mice genetically modified to overexpress SIRT6 had greater longevity than their controls. The effect was not observed in females, a difference that requires interpreting that result within its own experimental conditions.
Subsequent research has expanded knowledge about this protein. A study published in Cell analyzed 18 rodent species and found a relationship between SIRT6's ability to promote the repair of DNA double-strand breaks and the maximum longevity of the species studied.
Another paper, published in Nature Communications, found that overexpression of SIRT6 in mice reduced frailty and extended longevity, also being associated with better preservation of energy homeostasis during aging.
The hypothesis takes on an additional dimension when studying exceptionally long-lived people. In 2022, researchers identified in Ashkenazi Jewish centenarians a variant of SIRT6 — called centSIRT6 — associated with different activity of the protein. In cellular models, this variant showed a greater capacity to promote the repair of double-strand breaks and to limit the activity of genetic elements such as LINE-1.
A paper published in 2026 has delved deeper into these variants using human cellular models. The authors observed an increase in the SIRT6 protein, modifications in its enzymatic activity, and greater resistance to certain phenomena of cellular senescence. They also studied administration via AAV in cells from patients with progeria. These are mechanistic and preclinical results, not clinical evidence of an anti-aging therapy in people.
What does reducing epigenetic age really mean?
Here appears the most interesting part — and also the one that requires the greatest caution — of the announcement.
Epigenetic clocks calculate age from patterns of DNA methylation, a chemical modification that regulates the activity of numerous genes without altering the genetic sequence. Research has shown that certain methylation patterns change systematically with age.
In dogs, there are epigenetic clocks capable of estimating chronological age and studying certain characteristics associated with aging. A paper published in Cell Systems developed clocks applicable to dogs and humans and found methylation patterns conserved among different mammalian species.
This explains the interest in the result reported by Genflow: if an intervention favorably modifies an epigenetic clock, it may indicate that it has produced biological changes related to aging.
That does not mean, by itself, that the animal has rejuvenated, nor does it demonstrate that it will live longer.
And this distinction matters especially in longevity, a field in which the use of biological clocks as substitutes for clinical outcomes is growing rapidly.
A analysis published in 2024 on different methylation platforms used in dogs found relevant confounding factors, including population structure and differences between datasets. The authors note that building biological age clocks in dogs requires considerable parameterization and that signals related to biological age do not necessarily coincide across different studies and platforms.
That is why it will be especially important to know which GRIM clock was used, on which tissue the analysis was performed, what the exact magnitude of the change was, what difference existed between each group, and what the statistical significance was. Without that data, the expression “reduction in biological age” describes the result reported by the company, although it still does not allow its biological scope to be quantified.
From the molecule to the animal: the real test
The SLAB trial is also of interest for another reason. It is not limited to studying cells in a laboratory dish. It has been carried out in older dogs, animals that spontaneously develop many of the alterations associated with aging.
The intervention uses two approaches: plasmid DNA and an AAV8 viral vector. They are platforms with different pharmacological and delivery characteristics, so the results of each cohort will have to be analyzed separately.
The company had previously reported preliminary muscle-related data in February and three-month follow-up results in April. It now states that improvements were also observed in various functional and observational measures.
Precisely those data will be decisive in assessing the scope of the result. An epigenetic clock can indicate that certain molecular marks have changed. A functional improvement adds another dimension. And sufficiently prolonged follow-up would make it possible to verify whether those changes are maintained and whether they ultimately become associated with a lower incidence of age-related diseases, better physical function, or greater survival.
The current chain of evidence is attractive: SIRT6 has a solid experimental basis; certain human variants associated with exceptional longevity present particular biological properties; manipulation of SIRT6 has produced effects on longevity and health in animal models; and now Genflow reports a positive result in elderly dogs.
The distance to a human therapy remains considerable. There is still no clinical evidence demonstrating that administering a SIRT6-based gene therapy to people reduces their biological age, delays aging-associated diseases, or prolongs survival. The SLAB trial was also not designed to answer those questions.
The scientific interest of the study lies elsewhere: verifying whether an intervention targeting a specific aging mechanism can simultaneously modify molecular biomarkers and functional characteristics in a complex, aged organism.
That is considerably more interesting than simply talking about “rejuvenation.” The complete data that Genflow will present in Toronto will make it possible to know how much the epigenetic clock has changed, whether the effect appears consistently across animals and doses, what happened with muscle tissue, and, above all, whether the molecular modifications maintain a coherent relationship with the functional improvements.
Longevity needs precisely that kind of correlation: biomarker, mechanism, function, and clinical or vital outcome.
Until then, the SLAB trial represents a promising preclinical result that deserves to be studied with the complete data on the table. The news is not that a gene therapy has been shown to rejuvenate dogs. The scientific news is more specific: an intervention on SIRT6 has achieved the primary endpoint defined by Genflow by modifying an epigenetic marker of age in elderly dogs.
The difference between both statements is important. It will also be important to verify what the data say when they are published.
