UTC Imaging as a Clinical Trial Endpoint: Validating Tendon Assessment in Drug Research
Ultrasound tissue characterization is establishing itself as the standard method for objective tendon assessment in clinical practice. Now, it is taking on a broader role: as a validated imaging endpoint in pharmaceutical drug research. Causeway Therapeutics selected UTC as the structural imaging tool in their Phase 1, Phase 2, and upcoming Phase 3 clinical trials of TenoMiR®. That decision reflects the scientific rigour of the technology. Moreover, it signals where tendon diagnostics is heading.
The Problem with Conventional Tendon Imaging
Measuring what happens inside a tendon during treatment is harder than it sounds. Conventional greyscale ultrasound produces a two-dimensional image. That image depends heavily on the operator. As a result, findings vary between clinicians, between sessions, and between sites. In multi-centre clinical trials, that variability creates a serious problem. MRI offers anatomical detail, but it is expensive and slow. It is also impractical for repeated monitoring. In short, neither modality delivers the quantitative, standardized output that modern clinical research requires.
What Makes UTC Different
Ultrasound tissue characterization solves these problems directly. The UTC Tracker moves the probe in standardized steps of 0.2 mm and collects transverse images. Software then compiles these automatically into a 3D data block. From this block, the system quantifies four echo-types: intact aligned fibres (type I, green), wavy fibres (type II, blue), loose fibrillar matrix (type III, red), and amorphous tissue (type IV, black).
The resulting echo-type ratios correlate closely with tissue findings at a cellular level. Furthermore, operators across different sites produce consistent results — inter- and intraclass correlation coefficients consistently exceed 90%. In addition, a full scan takes less than 45 seconds. Together, that speed, objectivity, and inter-site consistency make UTC tendon assessment uniquely suited to clinical research.
TenoMiR®: Targeting the Molecular Root of Tendinopathy
Causeway Therapeutics is a spin-out from the University of Glasgow. The company develops TenoMiR® — a synthetic mimic of microRNA-29a (miR-29a). This small RNA molecule plays a central role in regulating collagen production in tendons. In healthy tissue, miR-29a suppresses excess collagen type 3, limits new blood vessel growth, and controls cell division.
However, when tendon injury occurs, miR-29a levels drop sharply. Without that signal, disease pathways switch on. Consequently, tendinopathy develops. TenoMiR® works by restoring miR-29a levels and switching off those pathways. The goal is genuine structural repair — not just symptom relief.
Phase 1: UTC as the Structural Imaging Standard
In their Phase 1b first-in-human trial, Causeway Therapeutics chose UTC as the structural imaging endpoint. The study design was prospective, randomized, double-blind, and placebo-controlled, with 24 patients with lateral epicondylitis. At all three dose levels, TenoMiR® produced a clear improvement in tendon structure over 90 days. Throughout the study, the safety profile remained acceptable.
Professor Neal Millar, co-founder and Chief Medical Officer of Causeway, stated: “Our Phase 1 trial used ultrasound tissue characterization as an endpoint in an interventional trial, and I am excited to continue exploring how this novel imaging modality can help us understand how repairing tendon structure impacts the course of disease.”
(University of Glasgow press release, February 2023)
That choice carries weight. When a researcher selects UTC over conventional imaging to measure treatment response, it is because the data it produces is more reliable and more precise.
Phase 2: Multi-Site Confirmation
In the Phase 2 trial, Causeway again selected UTC as the structural imaging endpoint. This multi-site, randomized, double-blind, placebo-controlled study enrolled 123 patients across the USA and UK. In the group that received the correctly delivered dose, TenoMiR® produced statistically significant improvements in pain, function, and tendon structure. Results held over the full 90-day follow-up period.
Selecting UTC across both trials — in a multi-site setting with patients at different clinical centres — directly confirms its inter-operator reliability. In a multi-centre trial, imaging results that shift with the operator introduce risk. UTC’s standardized protocol removes that risk entirely.
The Phase 2 results are, in Causeway’s own words, “the first robust evidence of disease-modifying regenerative potential in human tendon disease.” Therefore, Causeway is advancing to a Phase 3 study for lateral epicondylitis and a Phase 2 study in rotator cuff tendinopathy. Notably, UTC imaging will serve as the structural endpoint in both upcoming trials.
A Signal for the Field
The TenoMiR® programme reflects a broader shift in tendinopathy research. As new therapies emerge that claim to modify tendon disease at the tissue level, objective and reproducible structural measurement becomes essential. Indeed, that applies to trial design, regulatory approval, and clinical decision-making alike.
What It Means for Your Practice
For clinicians already working with UTC imaging, this development confirms what daily practice shows: ultrasound tissue characterization produces data that holds up under scientific scrutiny. For those considering adoption, it adds a strong argument. Ultimately, UTC is not only useful at the point of care — it is precise enough to serve as the benchmark in a pharmaceutical research programme spanning three clinical trial phases.
Read the Phase 1b preprint: Millar et al., medRxiv 2025. doi.org/10.1101/2025.08.23.25332854
About Causeway Therapeutics: causewaytx.com