Company Announcements

• Phase 1b data shows treatment with SAT-3247 was safe and well-tolerated
• Pharmacokinetic (PK) profile of SAT-3247 translated as expected to Duchenne Muscular Dystrophy (DMD) patients taking concurrent steroids
• Potential trend to improved grip strength observed, with average strength across the study participants doubling from ~2kg to ~4kg
• Study participants will have the option to enroll into an 11-month, long-term follow-up study
• Satellos plans to advance SAT-3247 into a placebo-controlled Phase 2 trial following additional data analysis and regulatory engagement

TORONTO--(BUSINESS WIRE)--May 22, 2025-- Satellos Bioscience Inc. (TSX: MSCL, OTCQB: MSCLF) (“Satellos” or the “Company”), a biotech company developing new small molecule therapeutic approaches to improve the treatment of muscle diseases and disorders, today announced promising Phase 1b data, in an open-label study treating five adult male DMD patients, ages 20 – 27, demonstrating early signs that SAT-3247 may have the potential to affect grip strength, which could represent a clinically meaningful measure for patients with DMD.

“We have gained valuable insights from this study of SAT-3247, and we are deeply grateful to the participants,” said Satellos Co-founder and Chief Executive Officer Frank Gleeson. “Given the short 28-day treatment window, the severity and variability of disease in this population, who have limited remaining muscle, we are encouraged by these initial data — particularly, the apparent trend of improved grip strength. Improvements in muscle strength have consistently been an early signal of a possible drug effect in our preclinical studies, where treatment with SAT-3247 led to notable increases in muscle force in both rodent and canine models of DMD. We believe the findings from this Phase 1b study support our plan to advance SAT-3247 into a placebo-controlled Phase 2 trial. We look forward to engaging with regulators and sharing more about our next steps.”

SAT-3247 is designed to address progressive muscle loss in DMD patients by aiming to restore regeneration in response to damage. The Phase 1b open-label trial of SAT-3247 was conducted in adults with DMD, with the primary endpoint being safety and tolerability. As additional endpoints, the study evaluated a number of exploratory measurements of a possible drug effect. The study focused on adults, a demographic representing individuals who have reached the later stages of the disease, where clinical management becomes increasingly complex and long-term survival is less common. All participants were maintained on their prescribed daily course of steroids during the study.

Summary of clinical results:

• SAT-3247 appeared to be safe and well tolerated in all study participants.
• The PK profile of SAT-3247 translated as expected to DMD patients on steroids, an important objective of the study.
• Grip strength was measured using the standardized MyoGrip measurement device. Across all study participants, an average doubling of strength from ~2kg to ~4kg was observed.
• Study participants appeared to remain stable in other exploratory measurement areas.

Satellos plans to begin an 11-month follow-up study, which has already received ethics committee approval in Australia. First-patient dosing is expected in Q3 2025, pending qualification of the clinical site. The study will incorporate MRI imaging to assess possible changes in muscle and will measure grip strength every three months to evaluate whether the observed improvements continue, as well as additional functional and biomarker measurements.

Satellos believes the Phase 1b findings support advancing SAT-3247 into a global, placebo-controlled Phase 2 proof-of-concept study in pediatric patients, for which global regulatory submissions are planned for the third quarter of 2025.

About Phase 1 DMD Trial with SAT-3247

The Phase 1 clinical trial of SAT-3247 was comprised of two components. In the first component, Phase 1a, 72 healthy volunteers were enrolled in a blinded, randomized, placebo-controlled, staggered, parallel design study to assess the safety and pharmacokinetic properties of SAT-3247. Participants were randomized across five SAD cohorts, four MAD cohorts, and one food effect cohort. In the second component, the Phase 1b portion of the trial, five adult volunteers with genetically confirmed DMD, all of whom were receiving their prescribed steroid treatments, were enrolled in a 28-day open-label single-dose cohort study to assess safety and pharmacokinetic properties and assess a range of exploratory measures including potential pharmacodynamic markers.

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, expected timing for a Phase 2 clinical trial and the intended Phase 1b long-term follow-up study; statements regarding the potential for SAT-3247 to represent a disease modifying approach to the 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; 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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20250522767784/en/

Investors: Liz Williams, CFO, ir@satellos.com
Media:Emily Williams, Senior Director, Communications, eawilliams@satellos.com
Clinical Trial Info: medicalinfo@satellos.com

Source: Satellos Bioscience Inc.