A New Hope for Aging Muscles: Immunis Drug Shows Promise in Seniors

IRVINE, Calif. – January 14, 2026 – A novel biologic therapy is showing significant promise in tackling one of the most debilitating aspects of aging: the combined loss of muscle and increase in fat. Immunis, a California-based biotech company, has announced positive interim results from a Phase 2 study of its drug, IMM01-STEM, demonstrating that it helped obese seniors with muscle weakness improve walking speed and lose weight while preserving crucial muscle mass.

The findings from the STEM-META trial represent a potential breakthrough not only for the millions of older adults facing mobility challenges but also for an emerging class of treatments known as “secretome-based biologics.” This study offers some of the first mid-stage clinical evidence validating these “cell-free cell therapies,” which aim to harness the healing power of stem cells without the risks of administering the cells themselves.

The Dawn of Secretome Therapy

For decades, the pharmaceutical industry has largely focused on single-target drugs designed to interact with one specific molecule or pathway implicated in a disease. However, many complex conditions, particularly those related to aging, arise from the dysregulation of numerous interconnected biological systems. Immunis is pioneering a different approach.

IMM01-STEM is a multi-active biologic derived from the secretome of partially differentiated stem cells. The secretome is the cocktail of beneficial molecules—including growth factors, cytokines, and other signaling proteins—that cells naturally release to communicate with each other, regulate the immune system, and promote tissue repair. By isolating these factors, Immunis has created a therapy that can theoretically influence multiple signaling pathways at once, orchestrating a more holistic regenerative response.

“Most diseases arise from dysregulation of complex cellular signaling pathways that are too intricate to correct with a single agent; yet scientists have been largely focused on single-target therapeutic approaches. The time has come to disrupt traditional paradigms in regenerative medicine," said Dr. Hans Keirstead, Chairman of Immunis, in a statement. “With the most advanced data yet on multi-active secretome-based biologics, we’re thrilled to validate the promise of our unique approach.”

This cell-free approach is seen as a significant step forward in regenerative medicine. It aims to deliver the therapeutic benefits of stem cell molecules while avoiding potential complications associated with cell transplantation, such as immune rejection or uncontrolled cell growth. Furthermore, such biologics are generally more stable and easier to manufacture, store, and administer on a large scale.

A Clinically Meaningful Step Forward

The STEM-META study, a double-blind, placebo-controlled trial involving 47 obese seniors with muscle weakness, provided compelling evidence of IMM01-STEM's potential. The most striking result was its effect on gait speed, a simple yet powerful indicator of overall health and longevity in older adults.

According to the interim data, subjects treated with IMM01-STEM saw their gait speed improve by 26% compared to those on placebo. The absolute improvement reached 0.12 meters per second after four weeks of treatment and an impressive 0.16 meters per second three months after treatment concluded. This figure is critical, as an improvement of just 0.1 m/s is widely recognized in geriatric medicine as a clinically meaningful change that positively impacts quality of life.

Gait speed is more than just how fast a person walks; it is a summary measure of physiologic reserve, reflecting the integrated function of the cardiovascular, pulmonary, neurological, and musculoskeletal systems. Slower gait speed is strongly correlated with an increased risk of falls, disability, hospitalization, and mortality. Improving it can enhance independence, physical fitness, and even cognitive health.

“These highly encouraging findings suggest IMM01-STEM offers significant improvements in overall physical function and health with gait speed being a key metric predicting biological age, physical and cognitive status, risk of hospitalization, disability and death,” noted Dr. Nicole Berchtold, Principal Scientist at Immunis. “This research tackles a pressing challenge for the expanding older-adult population, a demographic that is shaping the future of healthcare, the economy, and society at large.”

Addressing the Unmet Need of Sarcopenic Obesity

The trial specifically targeted individuals with sarcopenic obesity, a condition characterized by the insidious combination of age-related muscle loss (sarcopenia) and excess body fat. This "double trouble" pathology exacerbates frailty and metabolic dysfunction, severely diminishing quality of life. While sarcopenia is a universal process of aging, expected to affect everyone who lives long enough, there are currently no FDA-approved drugs to treat it. The standard of care remains diet and exercise, a regimen that can be difficult for elderly or frail individuals to maintain effectively.

The market for a safe and effective therapy is therefore vast and entirely unmet. The positive results from the STEM-META trial are built upon a strong foundation of preclinical research. Previous studies in aged mice, published in peer-reviewed journals like Aging Cell and GeroScience, showed that IMM01-STEM increased whole-body lean mass, reduced fat mass, improved muscle fiber size, and enhanced overall physical activity and grip strength. The new human data suggests these benefits may translate to patients, offering a potential pharmaceutical solution where none currently exists.

The Phase 2 study is a dose-expansion trial designed to assess safety, body composition, and muscle function across several dosing regimens. Following an initial four-week treatment period of twice-weekly injections, participants are monitored for changes in muscle strength, physical function, and a host of metabolic and inflammatory markers.

The Road Ahead

With the STEM-META trial still ongoing and actively enrolling patients, these interim results provide a promising glimpse into the future of IMM01-STEM. Immunis has indicated that it is concurrently exploring the biologic's potential in other musculoskeletal and metabolic diseases, as well as its application in veterinary medicine for companion animals like canines who suffer from similar age-related decline.

The FDA's clearance for this Phase 2 study, which followed a successful smaller Phase 1/2a trial for muscle atrophy in adults with knee osteoarthritis, signals a clear regulatory pathway for this novel class of therapy. As Immunis continues to gather data and advance its clinical program, the medical community will be watching closely. The success of IMM01-STEM could not only provide a much-needed treatment for an aging population but also validate the entire field of secretome-based biologics as a powerful new tool in the fight against complex, age-related diseases.