CHICAGO – With new results validating its PreveCol liquid biopsy test for colorectal cancer, Spanish diagnostic company Amadix is preparing for the US launch of its screening assay.
In data presented at the American Society of Clinical Oncology's annual meeting this week, the company showed its test had high sensitivity and specificity for both colorectal cancer detection and advanced adenoma detection — something that has been a struggle for many other colorectal cancer screening test developers.
The test detects a molecular signature of 11 proteins and 10 miRNAs by analyzing plasma samples via RT-qPCR and ELISA. Some of the biomarkers were licensed from a hospital in Spain, Amadix CEO Rocío Arroyo said in an interview. Machine learning techniques were then used to develop an ensemble algorithm that was trained on a cohort of 538 patients from 13 sites in Spain: 173 patients had colorectal cancer, 181 had advanced adenomas, and 184 were controls.
Along with the blood biomarkers, Arroyo noted, the algorithm incorporates risk factors garnered from a patient's electronic medical record.
After the algorithm was locked and the clinical cutoffs were established in the training cohort, Amadix then validated its test in a cohort of 3,163 patients from nine sites in Europe. Of those patients, 78 had colorectal cancer, 156 had advanced adenomas, and 2,783 were controls.
The test showed an area under the receiver operating curve of 92 percent for colorectal cancer detection, with sensitivity of 82 percent and specificity of 86 percent. For advanced adenomas, the test had an area under the curve of 87 percent, with sensitivity of 71 percent and specificity of 86 percent.
PreveCol also showed sensitivity of about 90 percent in identifying stage I and II colorectal cancer and lesions located in the proximal colon.
Arroyo noted that the test would serve as a first-line screening assay ordered by a general practitioner or gastroenterologist for patients older than 45, when a positive test result would indicate the need for a confirmatory colonoscopy, while a negative result would rule out a patient for further testing.
The firm is also working to add DNA methylation as a potential biomarker to further improve the test's performance, she added.
PreveCol has received CE marking in Europe and the company is aiming to start a clinical trial in the US for US Food and Drug Administration approval this year, Arroyo said. The test received breakthrough device designation from the FDA in December, and Amadix has been in discussions with the agency about the premarket approval process for the assay.
It is also seeking US partners with expertise in regulatory proceedings, reimbursement, and sales and distribution for help with the test's US commercialization, she added.
Blood-based colorectal cancer screening tests are under development at a variety of large and small companies, but early-stage, advanced adenoma, and precancerous lesion sensitivity have been a hurdle for many of those firms. In April, Freenome announced results from its PREEMPT CRC trial that underwhelmed investors. While the test's overall sensitivity reached approximately 79 percent, for stage I cancers, the assay had a sensitivity of just 57 percent. It rose to 100 percent for stage II tumors, dropped to 82.4 percent in stage III cases, and reached 100 percent sensitivity in stage IV cancers.
Fellow European company Mainz Biomed has seen more success with its ColoFuture study, where interim results showed the sensitivity of its test for detecting colorectal cancer was 94 percent, while precursor lesions including advanced adenomas were detected with 80 percent sensitivity. Specificity for colorectal cancer was nearly 97 percent, and specificity for advanced adenomas was 95 percent. However, the study included only 220 patients — much smaller than other companies' studies that showed lower sensitivity.
Guardant Health's Shield test, meantime, reported 83 percent sensitivity and 90 percent specificity in identifying patients who would go on to be diagnosed with colorectal cancer in the 20,000-patient ECLIPSE trial. Sensitivity for advanced adenomas was 13 percent, disappointing investors when the early results were announced in 2022.
"We don't see any other blood test with similar predictive capacity for detecting advanced adenomas and precancerous lesions," Arroyo said. "We believe we're in a good position today."
In addition to the colorectal cancer test, Amadix has an assay for pancreatic cancer, PancreaDix, and a test for lung cancer, DiagnoLung, in development that utilize blood biomarkers and diagnostic imaging data. The tests are also able to differentiate between benign nodules and malignant nodules, she noted.
The firm started with colorectal cancer because polyps develop slowly into cancerous tumors. From the time a polyp appears to it becoming a tumor can take between 10 and 12 years. "It's an important opportunity, having all this time to catch and identify polyps that could be removed through routine colonoscopy," Arroyo said.
She added that very few people actually undergo colonoscopies for screening due to the time and burden of preparation, so it made sense to commercialize a colorectal cancer screening test to help improve patient compliance with screening guidelines.
The company already has promising unpublished results from 1,000 patients each for its pancreatic and lung cancer tests and has recruited a "few thousand" patients in the European Union for further validation work for both tests, Arroyo said. Amadix is also planning to set up US-based studies for both tests by the end of 2024.