Stoke Therapeutics, Inc. (NASDAQ: STOK), a Massachusetts-based biotechnology company developing RNA medicines for genetic diseases, has presented new translational evidence supporting the potential of investigational STK-002 to address the underlying biology of autosomal dominant optic atrophy (ADOA), an inherited disorder that causes progressive vision loss. Announced on October 12, 2026, at the American Academy of Ophthalmology Annual Meeting in New Orleans, the findings connect increased OPA1 protein expression and improved mitochondrial function in preclinical models with observations from the company’s FALCON natural history study.
The presentations arrive as Stoke Therapeutics advances its first-in-human Phase 1 OSPREY trial, with dosing completed in the first two patient cohorts and the third cohort expected to finish dosing before the end of 2026. The company anticipates initial safety and exploratory efficacy findings from higher-dose cohorts during the first half of 2027, when investigators expect to begin assessing whether the biological activity observed in laboratory research translates into measurable changes in visual function.
The development is important because no medicines are currently approved specifically to treat autosomal dominant optic atrophy, which commonly causes visual impairment beginning in childhood. Unlike approaches aimed primarily at managing the consequences of optic nerve damage, STK-002 is designed to increase production of functional OPA1 protein, whose deficiency contributes to mitochondrial dysfunction and retinal ganglion cell degeneration. However, the latest presentations do not establish that the treatment improves vision in patients, and its proposed disease-modifying benefits remain a hypothesis undergoing clinical investigation.
How does STK-002 target the genetic cause of autosomal dominant optic atrophy?
Autosomal dominant optic atrophy is most frequently associated with disease-causing variants in the OPA1 gene, which provides instructions for producing a protein essential to mitochondrial structure and function. Mitochondria supply energy needed for cellular activity, and retinal ganglion cells are particularly dependent on effective energy production because their nerve fibres transmit visual information from the retina toward the brain. Impaired mitochondrial function can contribute to degeneration of these cells and progressive loss of vision.
Stoke Therapeutics estimates that approximately 65% to 90% of ADOA cases are caused by OPA1 variants, with more than 600 variants identified among affected individuals. Many produce a condition known as haploinsufficiency, in which one functioning copy of the gene cannot generate enough protein to maintain normal cellular activity. In the relevant genetic forms of ADOA, functional OPA1 protein expression may be reduced to approximately half its usual level.
STK-002 is an antisense oligonucleotide designed to increase the amount of functional OPA1 protein produced from the remaining healthy copy of the gene. Rather than replacing the defective gene through viral gene transfer or attempting to correct a specific mutation, the investigational medicine changes how RNA is processed. This approach could potentially address multiple disease-causing OPA1 variants that share the same underlying protein deficiency, although the range of variants that would respond clinically has not been established.
The programme uses Stoke Therapeutics’ proprietary Targeted Augmentation of Nuclear Gene Output platform, known as TANGO. The technology aims to prevent the inclusion of specific nonproductive RNA sequences during splicing, allowing a greater proportion of the resulting messenger RNA to produce functional protein. Its suitability depends on the genetic mechanism involved, meaning it cannot automatically be applied to every form of inherited optic atrophy.
What do the latest preclinical STK-002 findings demonstrate about OPA1 protein restoration?
The American Academy of Ophthalmology presentations highlighted evidence that STK-002 increases OPA1 expression through a mechanism that can operate across different OPA1 variants associated with protein deficiency. Stoke reported dose-dependent increases in retinal exposure, target engagement and OPA1 protein expression in preclinical studies. Researchers also observed improvements in mitochondrial function in patient-derived cells carrying different OPA1 variants.
These findings build on research published in Nucleic Acid Therapeutics in October 2024, which provided a detailed account of the molecule’s mechanism. That investigation found that STK-002 reduced inclusion of a naturally occurring nonproductive exon in OPA1 RNA, increasing functional protein production in laboratory models. Experiments involving fibroblasts derived from patients with ADOA also demonstrated improvements in measures of mitochondrial respiration after treatment.
The published research extended beyond cultured human cells into animal studies. Following intravitreal administration, investigators observed increased retinal OPA1 protein expression in rabbits and cynomolgus monkeys at four weeks, with the effect persisting at eight weeks in the monkey experiments. Researchers also identified evidence of STK-002 exposure and enhanced OPA1 expression in retinal ganglion cells, providing support for the intended route of delivery.
The distinction between molecular activity and clinical efficacy remains central to interpreting these results. Increasing OPA1 protein expression in laboratory systems demonstrates that the antisense approach can engage its intended biological target, while improvements in cellular respiration provide functional support for the mechanism. Neither result establishes that damaged human optic nerves can recover or that the treatment will prevent vision loss in patients.
The latest conference disclosure did not provide a new quantitative estimate of the percentage increase in OPA1 protein or a clinical treatment effect. Its contribution is therefore best understood as strengthening the scientific connection between disease biology, preclinical pharmacology and the ongoing first-in-human development programme.
Why does the FALCON natural history study matter for future ADOA treatment trials?
An important component of the October presentations involved Stoke Therapeutics’ FALCON natural history study, which followed 47 people with genetically confirmed ADOA over 24 months. The prospective observational programme was conducted across ten clinical sites in the United States, United Kingdom, Italy and Denmark, enrolling participants aged eight to 60 years. It collected repeated measurements of visual function and retinal structure without administering STK-002 or another investigational treatment.
The latest analysis found that people with ADOA exhibited higher levels of mitochondrial oxidative stress than healthy individuals, with greater stress associated with poorer visual acuity. These observations support the biological rationale for a treatment designed to restore OPA1 protein levels and improve mitochondrial function. However, the relationship is observational, and it does not establish that reducing oxidative stress will necessarily improve visual performance.
Earlier FALCON findings presented in October 2025 showed that approximately 24% of participants experienced a loss of at least five letters in low-contrast visual acuity over the two-year observation period. High-contrast visual acuity remained relatively stable in many participants, while investigators did not observe significant changes in the retinal anatomical measurements evaluated. This suggests that certain functional tests may detect disease progression that is less apparent through standard vision measurements over relatively short periods.
For clinical development, identifying sensitive outcome measures is especially important in disorders that can progress slowly and unpredictably. If a trial relies exclusively on an endpoint that changes very little over one or two years, a genuine treatment effect may be difficult to distinguish from ordinary measurement variation. Low-contrast visual acuity and related functional assessments could therefore help researchers identify meaningful changes during early therapeutic studies.
The relative stability of retinal structure also requires careful interpretation. Stoke’s researchers have suggested that functional impairment may sometimes precede irreversible structural loss, creating a potential opportunity for intervention. Nevertheless, an absence of measurable anatomical deterioration over two years does not prove that existing damage is reversible or that increasing OPA1 protein will restore lost retinal ganglion cells.
How is the Phase 1 OSPREY trial testing STK-002 in children and adults with optic atrophy?
OSPREY is an open-label, first-in-human Phase 1 study evaluating the safety, tolerability and systemic exposure of single ascending doses of STK-002 in people with OPA1-associated autosomal dominant optic atrophy. The programme is designed to include adults and children aged approximately six to 55 years with genetically confirmed disease. Adult dose-escalation testing precedes the planned paediatric component, subject to appropriate safety assessments.
The investigational medicine is administered through a single intravitreal injection into an affected eye. The trial follows a sequential cohort design in which participants receive increasing dose levels, allowing investigators to evaluate tolerability before advancing to higher exposures. The primary objectives concern safety and pharmacokinetics, while changes in visual performance, retinal structure and quality of life are assessed as secondary outcomes.
Stoke Therapeutics confirmed that the first two dose cohorts have completed dosing. The third cohort is expected to complete dosing by the end of 2026, with a fourth cohort planned subject to review of accumulating safety information. The company expects cohorts three and four to reach dose levels capable of producing measurable therapeutic activity, although this remains a development expectation rather than an established clinical finding.
The study is operating through eight clinical sites across the United Kingdom, Germany, Denmark, Italy and Austria. Its international design provides access to specialised neuro-ophthalmology centres experienced in evaluating rare inherited optic nerve disorders. Such expertise is important because eligibility confirmation, precise visual function testing and longitudinal assessment can be challenging in a genetically heterogeneous patient population.
The absence of a randomized control group is an important limitation of this early study. Changes observed after treatment will need to be interpreted against baseline measurements, natural disease variability and the knowledge gained from FALCON. OSPREY can generate valuable initial evidence, but a convincing demonstration of disease modification may eventually require larger controlled trials with sufficient follow-up.
Which visual function measurements could reveal whether STK-002 benefits patients?
OSPREY includes assessments designed to examine different aspects of optic nerve function rather than relying solely on conventional high-contrast visual acuity. Best-corrected visual acuity is being measured alongside low-contrast visual performance, visual field testing, retinal electrophysiology and structural imaging. Together, these measures could provide a more complete picture of whether treatment affects the function or condition of surviving retinal ganglion cells.
Low-contrast visual acuity is particularly relevant because the FALCON natural history study identified deterioration in this measurement among some participants despite relatively stable conventional vision assessments. A treatment-associated improvement or slower decline could therefore provide an early indication of altered disease activity. However, measurement repeatability, baseline impairment and the expected untreated rate of progression will be important when interpreting individual responses.
Optical coherence tomography provides information about retinal structures, including the retinal nerve fibre layer and ganglion cell complex. Investigators are also using electrophysiological testing to assess aspects of retinal function. These measurements may help determine whether an observed change in visual performance is accompanied by structural or physiological findings consistent with the proposed mechanism.
Quality-of-life assessments add another dimension because visual impairment can affect reading, mobility, education and independence. A meaningful clinical benefit might involve preserving important everyday functions rather than producing a dramatic improvement on a standard eye chart. Nevertheless, patient-reported outcomes in a small, open-label trial can be influenced by expectations and other factors, requiring cautious interpretation.
The central challenge is distinguishing a short-term change in visual testing from a sustained alteration in the underlying disease course. An apparent improvement in one measurement would be encouraging, but consistency across functional assessments, durability and subsequent controlled evidence would strengthen the case for disease modification.
What safety questions must STK-002 address before advancing into larger clinical trials?
The current evidence does not establish the safety or tolerability of STK-002 in a sufficiently characterized human population. Although two OSPREY dose cohorts have completed dosing, Stoke Therapeutics has not yet published detailed adverse-event rates, dose-limiting toxicities or patient-level safety outcomes from those cohorts. Completion of dosing should therefore not be interpreted as confirmation that the medicine is free of important safety risks.
Intravitreal administration carries procedural considerations, including the potential for ocular inflammation, infection and changes in intraocular pressure. Antisense oligonucleotides may also have molecule-specific effects on local tissues and immune responses, making careful monitoring necessary. The frequency and severity of any such events with STK-002 must be established from clinical data rather than inferred from other ophthalmic treatments.
Dose selection will be particularly important because the company expects higher cohorts to produce greater biological activity. Increased exposure may improve the possibility of target engagement, but it can also introduce additional tolerability considerations. The study’s sequential design allows investigators to examine emerging safety information before proceeding to further dose escalation.
Another question involves the persistence of OPA1 protein expression following treatment. The preclinical research demonstrated effects lasting several weeks in animal retinal tissue, but this does not establish how long a clinically meaningful response could persist in patients. Future studies may need to investigate repeat administration, treatment intervals and longer-term safety, depending on the results of the initial clinical programme.
Could STK-002 become the first disease-modifying treatment for inherited optic atrophy?
There are currently no approved medicines specifically for autosomal dominant optic atrophy, making a successful treatment targeting OPA1 deficiency potentially important for a population with limited therapeutic options. The disease affects an estimated one in 25,000 people globally, with a higher reported prevalence in Denmark associated with a founder effect. Clinical severity varies, and individuals with the condition can experience substantial limitations in visual function beginning in childhood.
Stoke Therapeutics has received orphan drug designation from the United States Food and Drug Administration for STK-002 as a potential ADOA treatment. The designation recognises the rare-disease development context and may provide regulatory incentives if applicable requirements are met. It does not represent marketing approval, establish efficacy or guarantee an accelerated clinical development outcome.
The treatment’s potential addressable population is also narrower than the entire inherited optic neuropathy market. OSPREY specifically requires a confirmed disease-causing OPA1 variant, and the therapeutic mechanism is intended primarily for forms involving insufficient functional protein production. Individuals with other genetic causes of optic atrophy, or mechanisms not appropriately addressed by increased expression from the healthy OPA1 copy, may not be suitable candidates.
Commercial adoption would eventually require specialised genetic diagnosis, neuro-ophthalmology assessment and access to centres capable of delivering and monitoring intravitreal treatment. The practical value of STK-002 would also depend on whether it can preserve useful vision, the timing of treatment relative to existing nerve damage and the durability of any clinical response. These questions remain beyond what the current preclinical and natural history data can establish.
How does the STK-002 programme fit into Stoke Therapeutics’ broader pipeline and finances?
STK-002 is an important second clinical development programme for Stoke Therapeutics, whose more advanced asset is zorevunersen, an investigational antisense oligonucleotide for Dravet syndrome. Zorevunersen is undergoing evaluation in the Phase 3 EMPEROR study, with 162 participants enrolled and a primary data readout expected in the third quarter of 2027. The company is separately preparing a potential United States regulatory submission strategy for that programme.
The shared technology platform creates opportunities to apply Stoke’s RNA-splicing approach across different genetic conditions involving insufficient protein production. However, success in Dravet syndrome would not establish that the platform can deliver equivalent clinical benefits in the eye. Differences in target tissue, dosing, disease progression and the biological consequences of protein restoration require separate clinical validation.
Stoke reported $354.3 million in cash, cash equivalents and marketable securities as of June 30, 2026. Following a subsequent equity sale generating $65.7 million in net proceeds, the company cited approximately $420 million in available financial resources on that combined basis. Management expects its financial position to support operations through a potential United States commercialization period for zorevunersen in early 2028, although this is a forward-looking estimate rather than a guarantee of funding sufficiency.
The company reported a second-quarter net loss of $61.6 million, compared with $23.5 million a year earlier, while research and development expenses increased to $49.5 million. Much of the additional spending related to advancing zorevunersen, illustrating the substantial cost of late-stage genetic disease development. STK-002 remains an earlier-stage asset whose future expenditure needs will depend on its clinical results and subsequent study design.
Stoke Therapeutics shares closed at $24.74 on October 9, 2026, a gain of approximately 3.3% during that trading session. Because the latest American Academy of Ophthalmology results were announced on October 12, the earlier gain cannot be attributed to the new data disclosure. The announcement is better understood as a translational research and clinical execution update than as a newly demonstrated efficacy event.
What must the first-half 2027 OSPREY readout demonstrate to support further development?
The first meaningful human data will need to establish whether STK-002 can be administered at potentially therapeutic dose levels with an acceptable safety and tolerability profile. Particular attention will be paid to ocular adverse events, systemic exposure and whether any findings suggest dose-dependent safety concerns. The company’s decision to continue into higher cohorts will depend on these assessments.
The exploratory efficacy evaluation will be more challenging because OSPREY is an early-stage, open-label study with relatively small patient cohorts. Investigators will need to examine whether treated individuals demonstrate changes in visual function that exceed ordinary testing variability and are credible in the context of the disease’s natural progression. The FALCON natural history findings provide a useful reference, but they do not replace an appropriately controlled comparison.
Evidence of improved visual acuity, contrast sensitivity or other functional outcomes would help bridge the gap between laboratory restoration of OPA1 protein and meaningful benefit for patients. Equally important will be whether any changes are accompanied by supportive structural or physiological measurements. A favourable signal might justify further clinical development without immediately establishing that the treatment prevents irreversible optic nerve damage.
The latest research provides a coherent scientific rationale for STK-002, connecting OPA1 insufficiency, mitochondrial dysfunction, antisense-mediated protein restoration and clinical measures of inherited vision loss. Its most important limitation is that the evidence for restored mitochondrial function currently comes from preclinical models rather than demonstrated improvements in patients. The planned first-half 2027 readout will begin to determine whether this molecular strategy can progress from promising biological activity to a clinically meaningful approach for preserving vision in people with autosomal dominant optic atrophy.
