Satellos Announces New Data Further Demonstrating Safety, Tolerability, and Functional Impact of SAT-3247 in First-in-Human Trial of Adults with Duchenne Muscular Dystrophy

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TORONTO--(BUSINESS WIRE)--Oct 10, 2025--

Satellos Bioscience Inc. (TSX: MSCL, OTCQB: MSCLF) (“Satellos” or the “Company”), a clinical-stage biotechnology company developing life-improving medicines to treat degenerative muscle diseases, today announced new data further demonstrating tolerability and initial efficacy of SAT-3247 in adults (aged 20-27 years) with Duchenne muscular dystrophy (Duchenne or DMD) at the 30 th Annual Congress of the World Muscle Society in Vienna, Austria.

“Satellos’ new and updated clinical results from the 28-day clinical study in adults with Duchenne provide an important validation of SAT-3247’s potential to be a safe and clinically meaningful treatment,” said Frank Gleeson, co-founder and CEO of Satellos. “We are excited and confident in progressing into our next phase of clinical studies with the objective of demonstrating the transformative potential of SAT-3247 to the Duchenne community.”

Data presented at the meeting demonstrate that SAT-3247 was safe and well-tolerated across the Phase 1a/b study with a desirable pharmacokinetic (PK) profile. The presentation also included new analyses of exploratory measures of early drug effect.

Individuals treated with SAT-3247 over a 28-day period demonstrated an increase in grip strength far greater than seen in the Duchenne natural history in this age group. Specifically, a 118.6% mean improvement in maximum grip strength was observed in the dominant hand and 97.9% mean improvement in the non-dominant hand, representing an approximate doubling of grip strength from ~2 kg to ~4 kg. These improvements are inconsistent with published natural history 1 and were correlated with higher drug concentrations on Day 15 and higher baseline creatinine (a surrogate for increased muscle mass), which we believe indicates our drug is having the desired impact on muscle.

Furthermore, participants exhibited a 5.8% mean improvement of predicted forced vital capacity; such an increase is also inconsistent with natural history with declines about 5% annually among adults with Duchenne 2. All other measures remained stable over the study period. No drug-related adverse events of moderate severity or higher were observed in either study, and no dose-limiting toxicities occurred.

“Satellos scientific co-founders were the first to recognize that the body’s innate process of muscle regeneration is severely impaired in Duchenne. They invented SAT-3247 with the aim of rebooting this impaired regeneration process, so that the body can once again repair and rebuild muscle,” said Wildon Farwell, M.D., Satellos chief medical officer. “These early signs of efficacy in adults with more advanced disease are incredibly encouraging and support expanding our clinical program to the broader Duchenne community. SAT-3247 has been designed to be a convenient, oral therapy with the potential to improve outcomes, regardless of an individual’s specific dystrophin mutation.”

The five adult patients, aged 20-27 years, who participated in the Phase 1b trial are now invited to enroll in an 11-month open-label, follow-up study of SAT-3247, which will also enroll additional males with DMD, aged 16-25 years. The primary endpoints of this study are to evaluate long-term safety and tolerability, as well as the effect of SAT-3247 on fat fraction in biceps brachii muscle. Secondary endpoints include the effect of SAT-3247 on fat fraction, and impact on muscle force and function. Once participants have completed their 3-month follow-up visit, the company will provide initial interim results.

Based on the initial safety and efficacy data from the Phase 1a/b trial, Satellos is also planning a Phase 2 randomized, double-blind, placebo-controlled, global, proof-of-concept study of SAT-3247 in ambulatory children with DMD. Primary endpoints will evaluate safety and tolerability of SAT-3247 and effect on muscle force. Secondary endpoints will evaluate SAT-3247’s impact on muscle quality, function, and regeneration. The company has recently submitted regulatory filings in the U.S. and globally to advance this study.

Full details from the poster presentations will be available on the Events and Presentations page of the Satellos website.

1. Hogrel, J.-Y., et al. 2020. Normalized grip strength is a sensitive outcome measure through all stages of Duchenne muscular dystrophy. J Neurol. 267(7):2022–2028. doi:10.1007/s00415-020-09800-9.
2. McDonald C.M., et al. 2018. Longitudinal pulmonary function testing outcome measures in Duchenne muscular dystrophy: Long-term natural history with and without glucocorticoids. Neuromuscul Disord. 28(11):897–909. doi:10.1016/j.nmd.2018.07.004.

ABOUT SAT-3247

SAT-3247 is a proprietary, oral, small molecule drug being developed by Satellos as a novel treatment to regenerate skeletal muscle that is lost in Duchenne muscular dystrophy and other degenerative or injury conditions. Satellos is advancing SAT-3247 as a potential treatment for DMD, independent of dystrophin and regardless of exon mutation status.

ABOUT SATELLOS BIOSCIENCE INC.

Satellos is a clinical-stage drug development company focused on restoring natural muscle repair and regeneration in degenerative muscle diseases. Through its research, Satellos has developed SAT-3247, a first-of-its-kind, orally administered small molecule drug designed to address deficits in muscle repair and regeneration. SAT-3247 targets AAK1, a key protein that Satellos has identified as capable of replacing the signal normally provided by dystrophin in muscle stem cells to effect repair and regeneration. By restoring this missing dystrophin signal in DMD, SAT-3247 enables muscle stem cells to divide properly and more efficiently, promoting natural muscle repair and regeneration. SAT-3247 is currently in clinical development as a potential disease-modifying treatment initially for DMD. Satellos also is leveraging its proprietary discovery platform MyoReGenX™ to identify additional muscle diseases or injury conditions where restoring muscle repair and regeneration may have therapeutic benefit and represent future clinical development opportunities. For more information, visit www.satellos.com.

NOTICE ON FORWARD-LOOKING STATEMENTS

This press release includes forward-looking information or forward-looking statements within the meaning of applicable securities laws regarding Satellos and its business, which may include, but are not limited to, statements regarding the transformative potential for SAT-3247 to represent a safe and effective therapeutic treatment of people living with Duchenne; anticipated benefits to patients from a small molecule treatment for Duchenne; the advancement SAT-3247 through clinical trials and the timing of those trials; the pharmacodynamic properties and mechanism-of-action of SAT-3247; the potential of our approach in other degenerative muscle diseases; its/their prospective impact on Duchenne patients, patients with other degenerative muscle disease or muscle injury or trauma, and on muscle regeneration generally; and Satellos’ technologies and drug development plans. All statements that are, or information which is, not historical facts, including without limitation, statements regarding future estimates, plans, programs, forecasts, projections, objectives, assumptions, expectations or beliefs of future performance, occurrences or developments, are “forward-looking information or statements.” Often but not always, forward-looking information or statements can be identified by the use of words such as “shall”, “intends”, “believe”, “plan”, “expect”, “intend”, “estimate”, “anticipate”, “potential”, “prospective” , “assert” or any variations (including negative or plural variations) of such words and phrases, or state that certain actions, events or results “may”, “might”, “can”, “could”, “would” or “will” be taken, occur, lead to, result in, or, be achieved. Such statements are based on the current expectations and views of future events of the management of the Company. They are based on assumptions and subject to risks and uncertainties. Although management believes that the assumptions underlying these statements are reasonable, they may prove to be incorrect. The forward-looking events and circumstances discussed in this release, may not occur and could differ materially as a result of known and unknown risk factors and uncertainties affecting the Company, including, without limitation, risks relating to the pharmaceutical and bioscience industry (including the risks associated with preclinical and clinical trials and regulatory approvals), and the research and development of therapeutics, the results of preclinical and clinical trials, general market conditions and equity markets, economic factors and management’s ability to manage and to operate the business of the Company generally, including inflation and the costs of operating a biopharma business, and those risks listed in the “Risk Factors” section of Satellos’ Annual Information Form dated March 26, 2025 (which is located on Satellos’ profile at www.sedarplus.ca ). Although Satellos has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking statements, there may be other factors that cause actions, events or results to differ from those anticipated, estimated or intended. Accordingly, readers should not place undue reliance on any forward-looking statements or information. No forward-looking statement can be guaranteed. Except as required by applicable securities laws, forward-looking statements speak only as of the date on which they are made and Satellos does not undertake any obligation to publicly update or revise any forward-looking statement, whether resulting from new information, future events, or otherwise.

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SOURCE: Satellos Bioscience Inc.

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PUB: 10/10/2025 09:45 AM/DISC: 10/10/2025 09:46 AM

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