Oxford University Study Unveils Breakthrough Radiotracer for Non-Invasive Endometriosis Diagnosis

University of Oxford researchers unveil maraciclatide, a molecular imaging agent that detects superficial endometriosis missed by MRI and ultrasound scans.

By: AXL Media

Published: Apr 30, 2026, 5:03 AM EDT

Source: Information for this report was sourced from the University of Oxford and The Lancet Obstetrics and Gynaecology

Molecular Imaging Targets Angiogenesis in Endometriotic Lesions

A major hurdle in women’s reproductive health may soon be overcome following the successful Phase 2 trial of maraciclatide, a gamma-emitting radiotracer developed by Serac Healthcare and the University of Oxford. The diagnostic agent works by binding to $\alpha v\beta 3$ integrin, a protein that is significantly upregulated during angiogenesis—the formation of new blood vessels. Because angiogenesis is a hallmark of inflammatory endometriotic tissue, the tracer allows clinicians to visualize lesions using SPECT-CT scans. This molecular approach provides a functional view of the disease, rather than a purely structural one, allowing for the detection of active endometriosis regardless of its location in the body.

Identifying "Invisible" Superficial Peritoneal Endometriosis

The DETECT study specifically addressed the diagnostic gap for superficial peritoneal endometriosis (SPE), which accounts for approximately 80% of all cases. Unlike deep endometriosis or ovarian cysts, SPE is notoriously difficult to identify using conventional imaging modalities like transvaginal ultrasound or MRI. In the trial, ten participants with surgically confirmed SPE had undergone traditional imaging within the previous year, all of which had failed to detect the disease. Maraciclatide, however, successfully visualized these lesions, showing a high correlation with subsequent laparoscopic findings. This capability could fundamentally shift the diagnostic pathway, moving it away from "surgery-first" protocols.

High Accuracy and Zero False Positives in Phase 2 Results

The clinical data from the 20-participant exploratory study demonstrated remarkable precision. Imaging results were concordant with the surgical presence or absence of endometriosis in 16 out of 19 cases. Notably, the radiotracer successfully imaged 14 out of 17 surgically positive participants, including rare and difficult-to-diagnose cases of thoracic endometriosis. Furthermore, the study reported zero false positives, a critical metric for any new diagnostic tool intended to guide surgical or medical intervention. Participants reported that the intravenous agent was well-tolerated, with high levels of patient acceptability across different demographic groups, including those on hormone therapy.