Actimed Therapeutics has launched a new development program to investigate whether its lead compound S-pindolol benzoate (ACM-001.1) can preserve muscle mass in obese patients treated with GLP-1 receptor agonists (GLP-1RAs). The UK-based clinical stage pharmaceutical company announced on May 20, 2025, that the initiative aims to address a significant side effect of popular weight loss medications – the loss of lean body mass alongside fat.
The program consists of two complementary parts: a preclinical study that has already completed its in vivo phase, and an upcoming Phase 2a clinical trial called PROACT (Preserving, Restoring, and Optimising lean mass and muscle with ACTAs), which is expected to begin enrolling patients by mid-year.
Addressing the Muscle Loss Challenge with GLP-1 Therapies
While GLP-1 receptor agonists have revolutionized obesity treatment with their ability to significantly reduce fat mass, clinical data has revealed a concerning trend. These medications frequently cause unwanted reduction in lean body mass, including skeletal muscle, which can be particularly problematic for older or frail individuals.
"We are extremely excited to announce the launch of this new development programme, PROACT, which is a natural extension of our mission to address serious muscle wasting conditions," said Robin Bhattacherjee, Actimed CEO. "We believe the use of S-pindolol benzoate in patients receiving or who have received GLP-1RAs represents a highly promising therapeutic strategy."
Another challenge occurs when patients discontinue GLP-1RA therapy, as this often results in weight rebound that favors fat accumulation over muscle, leading to a less favorable body composition than before treatment.
S-pindolol Benzoate: A Dual-Action Approach
S-pindolol benzoate has shown promise as an agent with both pro-anabolic and anti-catabolic properties in previous studies of cancer cachexia, demonstrating improvements in muscle mass. These characteristics make it a potential candidate for addressing the muscle preservation needs of patients on GLP-1RA therapy.
Additionally, through its β1-adrenoreceptor blocking effects, S-pindolol may enhance the cardiovascular benefits already associated with GLP-1RAs, potentially offering a complementary therapeutic approach.
Dr. David Ebsworth, Actimed Executive Chairman, emphasized the strategic importance of this program: "This programme represents a thoughtful and strategic expansion of our development pipeline. By leveraging the unique properties of S-pindolol benzoate in combination with GLP-1RAs, we are addressing a significant unmet need while remaining firmly aligned with our strategic focus on muscle wasting disorders."
The PROACT Clinical Trial
The Phase 2a PROACT trial will evaluate the safety and efficacy of S-pindolol benzoate in obese patients during and after GLP-1RA therapy. This study represents a significant step in determining whether the compound can effectively preserve muscle mass in this patient population.
The trial builds upon previous clinical experience with S-pindolol, which has already generated promising Phase 2a proof-of-concept data in cachexia patients. Actimed has also conducted pharmacokinetic and pharmacodynamic studies of S-pindolol benzoate to better characterize this new formulation.
Broader Pipeline and Strategic Focus
While expanding into this new therapeutic area, Actimed Therapeutics remains committed to its core focus on treating muscle wasting disorders, particularly cancer cachexia. The company continues to develop S-pindolol benzoate for cancer cachexia and is working to secure funding for its IMPACT clinical program.
Actimed's pipeline also includes S-oxprenolol (ACM-002), which is being developed for muscle wasting in amyotrophic lateral sclerosis (ALS). The company recently received US Orphan Drug Designation for S-oxprenolol in ALS in 2024, highlighting the potential significance of this treatment approach.
The company has licensed the global rights to develop and commercialize S-oxprenolol for cancer cachexia and other indications outside of ALS to US-based Faraday Pharmaceuticals.
Market Context and Unmet Need
The development of therapies to preserve muscle mass during weight loss represents an important emerging area in metabolic health. As GLP-1 receptor agonists continue to gain popularity for obesity management, addressing their limitations becomes increasingly important for optimizing patient outcomes.
Cachexia and muscle wasting remain significant clinical challenges across multiple disease states. In cancer patients, cachexia is associated with increased mortality, with estimates suggesting it may be responsible for up to 20% of all cancer deaths. A recent meta-analysis demonstrated that cachexia was associated with an 82% higher relative risk of mortality in patients with non-small cell lung cancer compared to those without cachexia.
Despite the clinical significance of muscle wasting conditions, there are currently no globally approved drugs specifically for the treatment or prevention of cancer-related cachexia, underscoring the potential impact of Actimed's development programs.
