NIH backs Greenstone Biosciences iPSC and AI programme for Duchenne cardiomyopathy

Greenstone Biosciences has received a Catalyze R61 award from the National Heart, Lung, and Blood Institute, part of the National Institutes of Health, to pursue new drug candidates for myocardial fibrosis and dilated cardiomyopathy associated with Duchenne muscular dystrophy. The Palo Alto biotechnology company plans to combine patient-derived induced pluripotent stem cell models with proteomics, computational screening and generative artificial intelligence to identify and validate potential treatments. The award moves Greenstone deeper into a disease area where cardiac deterioration has become increasingly important as improvements in respiratory and supportive care extend survival. However, the programme remains at an early discovery stage, meaning the critical test is whether Greenstone can convert its human-relevant disease models into sufficiently compelling targets and compounds to progress into later preclinical development.

The R61 award is part of a staged National Institutes of Health funding mechanism. Greenstone said the current phase will support target identification and early candidate discovery, while successful completion could lead to an R33 phase covering synthesis, characterization and in vivo testing of promising compounds before potential investigational new drug-enabling studies. The company did not disclose the monetary value of the new award in its announcement.

For Greenstone, the significance extends beyond another research grant. The programme provides an opportunity to demonstrate whether the company’s combination of human induced pluripotent stem cells, disease modelling and artificial intelligence can generate therapeutic assets rather than primarily functioning as a discovery and testing platform.

Why does Greenstone Biosciences’ NIH R61 award matter for Duchenne muscular dystrophy cardiomyopathy?

Duchenne muscular dystrophy is an inherited disorder caused by mutations affecting dystrophin, a protein needed for muscle stability. The disease is generally associated with progressive skeletal-muscle deterioration, but cardiac involvement has become an increasingly important part of long-term disease management.

Progressive myocardial fibrosis can contribute to ventricular dysfunction and dilated cardiomyopathy in people with Duchenne muscular dystrophy. Contemporary clinical literature describes myocardial disease involving progressive fibrosis and eventual dilated cardiomyopathy as becoming almost universal by adulthood, with heart and respiratory complications accounting for a substantial share of morbidity and mortality.

That creates a therapeutic challenge distinct from treating skeletal-muscle degeneration itself.

Current cardiac management can include surveillance and conventional cardiovascular therapies intended to preserve heart function or delay deterioration. Corticosteroid treatment used in Duchenne muscular dystrophy may also provide cardiovascular benefits in some patients. Yet there remains no approved treatment specifically designed to directly reverse or eliminate the myocardial fibrotic process driving much of the structural damage.

Greenstone is therefore targeting a part of the disease where the unmet need is not simply another improvement in muscular function. It is attempting to intervene in a pathological process that can progressively compromise the heart even as other areas of Duchenne treatment improve.

That distinction could become more commercially relevant if broader advances in Duchenne therapy continue to extend patients’ lives. Longer survival can increase the importance of controlling chronic cardiac complications that historically might have emerged later in the disease course.

How will Greenstone use patient-derived iPSCs and artificial intelligence to search for cardiac fibrosis drugs?

Greenstone’s strategy begins with induced pluripotent stem cells, or iPSCs. These are cells that can be reprogrammed and subsequently differentiated into specialised cell types, including cardiomyocytes and cardiac fibroblasts.

The attraction for drug discovery is straightforward. Instead of relying exclusively on an animal model to approximate human disease, researchers can study cells carrying genetic and biological characteristics derived from actual patients.

Greenstone says its broader biobank now incorporates samples from more than 2,500 donors, including rare and orphan disease cell lines. For the Duchenne programme, the company intends to use patient-derived cardiomyocyte disease models alongside proteomics to investigate biological pathways associated with myocardial fibrosis and cardiomyopathy.

Computational drug screening and generative artificial intelligence will then be used to identify potential therapeutic candidates.

The commercial argument behind this model is that more human-relevant screening could help eliminate weak or unsafe candidates earlier in development. Drug discovery remains expensive partly because biological findings that appear promising in simplified laboratory systems or animal models do not always translate successfully into humans.

Greenstone’s approach does not remove that translational risk. Any candidate emerging from the programme would still require extensive preclinical validation and, ultimately, human clinical trials.

What it potentially changes is the quality of evidence available before those expensive stages begin.

A platform capable of identifying disease mechanisms in patient-derived cells, screening compounds against those mechanisms and simultaneously evaluating potential toxicity could theoretically improve candidate selection. The important word, however, is theoretically. The NIH-backed Duchenne programme now gives Greenstone another opportunity to generate evidence that its platform can deliver clinically relevant drug candidates.

Why is Greenstone’s earlier Duchenne muscular dystrophy research important to the new programme?

The National Institutes of Health award is not Greenstone’s first attempt to apply patient-derived stem cells to Duchenne muscular dystrophy.

The California Institute for Regenerative Medicine previously awarded Greenstone Biosciences $675,000 for a discovery-stage programme focused on drug discovery for Duchenne muscular dystrophy using patient-derived human iPSCs.

Under that project, Greenstone developed and characterised iPSC-derived heart cells from multiple Duchenne muscular dystrophy patients. According to the California Institute for Regenerative Medicine’s project reporting, those cells reproduced disease-related phenotypes and provided a platform for studying differences between patients as well as drug discovery.

That earlier programme is significant because the new NIH award is not starting from an entirely untested conceptual foundation.

Greenstone has already invested in building disease-specific cellular models. The new programme appears to move further downstream by combining those capabilities with proteomic analysis and computational discovery to identify targets and potential therapeutic molecules directed more specifically at cardiac fibrosis and cardiomyopathy.

This progression matters commercially. Platform biotechnology companies can accumulate impressive datasets and research collaborations without necessarily creating proprietary drug programmes capable of generating substantial future value.

The transition from modelling disease to discovering compounds is therefore an important one.

If Greenstone can repeatedly use its cell resources and computational infrastructure to generate candidates across different diseases, its platform could support several business models, including internal therapeutic development, licensing, pharmaceutical partnerships and research services.

Could Greenstone’s previous cardiac fibrosis research give the NIH programme a stronger scientific foundation?

Greenstone has also participated in research extending beyond Duchenne muscular dystrophy that provides useful context for its fibrosis strategy.

A 2024 study published in Cell used human iPSC-derived cardiac fibroblasts in a high-throughput screening programme and identified artesunate as a potential antifibrotic compound. The work linked its activity to the myeloid differentiation factor 2 and Toll-like receptor 4 signalling pathway and combined human cell models with engineered heart tissues and animal studies.

Greenstone researchers were among the contributors to that work.

A subsequent Nature study published in 2025 examined a different mechanism involved in cardiac fibrosis. Researchers identified the tyrosine kinase SRC as a mechanosensor involved in persistent fibroblast activation and found that combining SRC inhibition with suppression of transforming growth factor beta signalling could reduce fibrotic activity in experimental models.

Greenstone contributed computational screening capabilities to the research, which identified saracatinib as a compound of interest.

Neither study establishes that Greenstone has an approved antifibrotic medicine, and findings from laboratory and animal models cannot be assumed to translate into clinical benefit.

What the research does establish is continuity.

The new Duchenne programme is connected to a broader body of work involving cardiac fibroblasts, human stem-cell models, computational screening and fibrosis biology. That makes the NIH award more strategically meaningful than an isolated entry into an unfamiliar therapeutic area.

Why is the FDA shift toward New Approach Methodologies important for Greenstone Biosciences?

The timing also intersects with a substantial change in the United States regulatory environment surrounding New Approach Methodologies, commonly known as NAMs.

Greenstone has built much of its business around human-derived cellular models and computational tools intended to supplement or, where scientifically appropriate, reduce reliance on conventional animal testing.

The U.S. Food and Drug Administration published a roadmap in April 2025 outlining plans to reduce animal testing in some drug-development programmes and encourage greater use of technologies including organoids, cell-based systems and computational models.

In April 2026, the regulator reported progress implementing the strategy and continued expanding the infrastructure intended to support human-relevant testing approaches.

Congress has also been considering further changes. The U.S. House of Representatives passed the FDA Modernization Act 3.0 on July 20, 2026, legislation intended to require updated Food and Drug Administration regulations concerning nonclinical testing methods.

The direction is strategically favourable for companies developing NAM technologies, but it should not be interpreted as automatic regulatory acceptance of every new model.

Validation remains the important barrier.

Regulators need evidence that a particular model is reproducible, appropriately validated and relevant to the scientific question being answered. Drug developers similarly need evidence that adopting a new approach improves decision-making rather than simply adding another layer of experimentation.

That means Greenstone’s competitive advantage will depend less on the general regulatory enthusiasm surrounding NAMs and more on whether its specific assays generate predictive information that pharmaceutical developers and regulators trust.

What must Greenstone prove before the NIH-backed Duchenne programme can become a clinical drug opportunity?

The immediate objective is target and candidate discovery, not clinical development.

Greenstone must first identify biological targets sufficiently linked to Duchenne-associated myocardial fibrosis to justify therapeutic intervention. It then needs compounds capable of modulating those targets with an acceptable activity and safety profile.

The proposed R33 stage would provide another important filter. Greenstone said advancement would allow promising compounds to undergo synthesis, characterization and in vivo testing before potential IND-enabling development.

Each transition materially increases the evidentiary burden.

A candidate that performs well in patient-derived cells may fail in more complex biological systems. A compound demonstrating activity against fibrosis could have pharmacokinetic or toxicity characteristics that limit its usefulness. And a successful preclinical programme would still face the substantially higher bar of demonstrating safety and meaningful clinical benefit in patients.

The value of the R61 award is therefore best viewed as validation of a research direction rather than validation of a medicine.

For Greenstone, however, reaching even a credible development candidate could be strategically important. Rare-disease drug development frequently involves partnerships, licensing transactions and external financing well before commercialisation. A candidate supported by differentiated human disease models and reproducible mechanistic evidence could potentially attract interest from larger biotechnology or pharmaceutical companies.

Key takeaways from Greenstone Biosciences’ NIH Duchenne cardiac fibrosis programme

• Greenstone Biosciences has received a National Institutes of Health Catalyze R61 award for drug discovery targeting myocardial fibrosis and dilated cardiomyopathy in Duchenne muscular dystrophy.
• The award comes from the National Heart, Lung, and Blood Institute.
• Greenstone will combine patient-derived induced pluripotent stem cell models, proteomics, computational drug screening and generative artificial intelligence.
• The current R61 stage concentrates on target identification and early drug-candidate discovery.
• Successful completion could lead to an R33 phase supporting compound synthesis, characterization and in vivo testing before potential IND-enabling studies.
• Greenstone previously received $675,000 from the California Institute for Regenerative Medicine for Duchenne muscular dystrophy drug discovery using patient-derived iPSCs.
• Its researchers have also contributed to published work investigating potential therapeutic mechanisms and compounds for cardiac fibrosis.
• The FDA’s increasing emphasis on New Approach Methodologies creates a more supportive regulatory environment for human-relevant cell and computational models.
• The programme nevertheless remains preclinical, and neither the NIH grant nor earlier fibrosis findings demonstrate clinical efficacy.
• The next meaningful proof point will be whether Greenstone identifies a validated target and drug candidate strong enough to progress into the R33 development stage.

What will determine whether Greenstone can turn its DMD fibrosis platform into a viable therapeutic programme?

The NIH R61 award strengthens Greenstone Biosciences’ position at the intersection of three rapidly developing areas: rare-disease therapeutics, human-derived disease modelling and artificial intelligence-assisted drug discovery. More importantly, it gives the company a defined programme through which those technologies can be judged by therapeutic output rather than platform capability alone.

Greenstone already has pieces of the scientific infrastructure needed for that test. It has patient-derived iPSC resources, earlier Duchenne disease models, experience in cardiovascular drug discovery and published research connecting its computational capabilities with fibrosis biology.

What remains unresolved is the hardest part of biotechnology development: whether those capabilities can generate a molecule with properties strong enough to survive progressively more demanding preclinical and clinical testing.

The R61 award therefore represents a useful inflection point rather than a destination. The decisive evidence will come if Greenstone can identify a reproducible disease mechanism, nominate a differentiated drug candidate and earn progression into the R33 stage. Achieving those milestones would begin to demonstrate that its human-first discovery platform can do more than model difficult diseases. It could show that the same infrastructure can produce therapeutics capable of entering the conventional drug-development pipeline.