New KYZATREX® Study Targets Quality of Life in Older Men

RALEIGH, NC – January 08, 2026 – Marius Pharmaceuticals has announced the initiation of a new clinical study for its oral testosterone therapy, KYZATREX®, focusing on men aged 65 to 80 with hypogonadism. The move signals a significant effort to gather data on a patient population at the center of a long-standing medical debate and could pave the way for a potential label expansion into the lucrative but heavily scrutinized market for age-related testosterone decline.

The Raleigh-based company's post-marketing study will evaluate how the testosterone undecanoate capsules affect broader health measures beyond just hormone levels. This research comes as millions of older men navigate the symptoms of declining testosterone, often in a regulatory gray area where the benefits and risks of treatment remain contentious.

The High Stakes of 'Age-Related' Testosterone Decline

The market for testosterone replacement therapy (TRT) has exploded over the past two decades, growing into a multi-billion dollar industry. A substantial portion of this growth has been driven by men over 40 seeking relief from symptoms like fatigue, reduced libido, and loss of muscle mass—hallmarks of what is often called “age-related” or “late-onset” hypogonadism. Data has shown that prescription rates for men over 60 have quadrupled in a single decade, with a significant number of these prescriptions written off-label, meaning for uses not officially approved by regulators.

This trend has drawn sharp scrutiny from the U.S. Food and Drug Administration (FDA). The agency’s official stance is that testosterone products are approved only for men with hypogonadism caused by specific medical conditions, such as genetic disorders or damage to the testes or pituitary gland. The FDA has repeatedly stated that the safety and efficacy of these drugs have not been established for treating the natural decline in testosterone due to aging. In 2014, an advisory panel voted to restrict TRT use for age-related decline, emphasizing the lack of evidence for its benefits and concerns over potential risks. This regulatory caution has left a massive demographic of symptomatic older men and their clinicians in a difficult position, balancing potential quality-of-life improvements against unquantified long-term risks.

A Study Designed for a New Frontier

Marius Pharmaceuticals' new study appears custom-designed to address the evidence gap highlighted by the FDA. The six-month, open-label trial will enroll 50 men aged 65–80 with confirmed hypogonadism and will assess outcomes that directly impact daily living. Instead of focusing narrowly on testosterone concentrations, investigators will evaluate changes in overall quality of life, cardiovascular parameters, body composition, strength-related measures, and inflammation.

“Marius is committed to advancing the understanding of men’s health across all ages, and this study reflects our interest in evaluating outcomes that matter most to older patients,” said Om Dhingra, Chief Scientific Advisor & Board Director at Marius, in the company's press release. “By focusing on cardiovascular markers, body composition, strength, and inflammation, we hope to generate insights that can help clinicians care for this growing patient population.”

Another critical component of the trial is its evaluation of a simplified once-daily dosing regimen alongside KYZATREX’s currently labeled titration protocol. For an older population that may be managing multiple medications, a simpler, easy-to-follow treatment plan could significantly improve adherence and overall treatment success, a practical consideration that is often overlooked in clinical research.

Navigating a Complex Web of Risks and Benefits

The central challenge for any TRT in an older population is balancing its potential benefits against a complex profile of risks. Proponents point to studies showing that TRT can offer modest but meaningful improvements in mood, energy, sexual function, and physical strength. Research has also demonstrated benefits for bone density, which is critical for preventing fractures in the elderly, and has shown potential for improving metabolic health and correcting anemia.

However, these benefits are weighed against significant safety concerns. The cardiovascular risk associated with TRT has been a subject of intense debate for years. While the FDA has removed its most severe boxed warning related to heart attacks and strokes, it added a warning about the risk of increased blood pressure, which was the most common side effect seen in KYZATREX's initial phase 3 trial. Recent large-scale studies have provided some reassurance, suggesting TRT was not associated with an increased risk of major adverse cardiovascular events, but the same studies noted a higher incidence of pulmonary embolism and atrial fibrillation in the treatment group.

Prostate health is another major concern. While current evidence suggests TRT does not cause new prostate cancers, it can potentially stimulate the growth of existing cancers and has been linked to a higher risk of benign prostatic hyperplasia (BPH), which causes urinary issues. Consequently, careful screening and monitoring are essential for any older man considering therapy. Marius's study, with its focus on key health markers including cardiovascular parameters, aims to provide clearer, real-world data to help both doctors and patients navigate this complex decision-making process.

Marius's Strategic Push in a Competitive Market

This study is not just a scientific endeavor; it is a calculated strategic move by Marius Pharmaceuticals. As a specialty company founded in 2017 with a singular focus on hypogonadism, Marius is positioning its lead asset, KYZATREX®, to capture a unique and underserved segment of the market. The oral TRT landscape includes competitors like Jatenzo® and Tlando®, which also use a testosterone undecanoate formulation absorbed through the lymphatic system to avoid liver toxicity.

However, by proactively generating safety and efficacy data specifically in the 65-80 age group, Marius could achieve a critical differentiator. If the results are positive, the company could pursue a label expansion that would make KYZATREX® the only TRT formally indicated for use in this older demographic, moving its use from the off-label gray area into mainstream, evidence-backed medicine. This would provide a powerful marketing advantage and a compelling reason for clinicians to choose it over competitors.

Furthermore, with a reported lower price point compared to some rivals, KYZATREX® could become an accessible option for a population often on fixed incomes. The successful completion of this study and subsequent regulatory engagement will be closely watched by investors, competitors, and the medical community, as it could redefine the standard of care for a growing population of aging men.