MiraDx has launched PROSTOX Standard, a latest genetic test designed to help personalise radiation therapy for men with localised prostate cancer, the molecular diagnostics company announced Tuesday.
The test identifies patients at increased risk of developing long-term urinary side effects following conventionally fractionated or moderately hypofractionated radiation therapy (CFRT or MHFRT). It complements MiraDx’s existing PROSTOX Ultra test, which is used for patients being considered for stereotactic body radiation therapy (SBRT). The launch expands access to genetic risk assessment for a broader range of prostate cancer patients undergoing external beam radiation therapy (EBRT).
More than 20% of patients treated with radiation therapy for prostate cancer experience persistent urinary side effects, known as late genitourinary (GU) toxicity, according to MiraDx. These side effects – including urinary urgency, leakage, or discomfort – can significantly diminish quality of life, appearing months or years after treatment.
PROSTOX tests aim to predict the onset of these late-onset GU toxicities. Localised prostate cancer has a high five-year survival rate, exceeding 99%, but individual responses to different radiation treatment methods – SBRT, CFRT, and MHFRT – can vary based on a patient’s genetic makeup. Previously, clinicians lacked a biology-driven tool to assess risk for GU toxicity specific to each EBRT method, the company stated.
The PROSTOX tests analyse inherited genetic variants in microRNAs and their associated pathways, which influence how patients tolerate radiation. A simple cheek swab provides the sample needed for analysis, with results delivered within 5-7 days. This allows physicians and patients to create more informed decisions about radiation treatment, based on individual risk profiles.
“PROSTOX tests bring precision medicine to radiation oncology by shifting the focus from the tumor alone to determining the most effective treatment approach for each patient based upon their unique biology and resulting treatment risks,” said Melissa C. Stoppler, MD, Executive Vice President of Medical Affairs at MiraDx. “Having information about which type of radiation each patient will tolerate best allows clinicians to better tailor radiation treatments to patients, helping them avoid future long-term side effects.”
The company emphasized that the two tests, PROSTOX Standard and PROSTOX Ultra, evaluate genetic risk across different radiation therapy regimens. A high-risk result on PROSTOX Standard does not necessarily indicate a high-risk result on PROSTOX Ultra, and vice versa. In a small percentage of cases – less than 2% of patients – both tests may identify a high risk for late GU side effects with both SBRT and CFRT/MHFRT, potentially prompting consideration of alternative interventions.
Ron Stewart, a patient who underwent PROSTOX testing, stated, “Being diagnosed with prostate cancer is life altering and comes with many decisions and so much uncertainty. The PROSTOX test helped me feel more confident about my treatment plan and more optimistic that my cancer treatment would not hamper my quality of life down the road.”
A recent study, published in the Journal of Health Economics and Outcomes Research, suggests that microRNA-based assays like PROSTOX may reduce costs and improve quality-adjusted life years (QALYs) in prostate cancer patients, according to reporting from Urology Times. Another report from BioSpace highlighted that a new publication demonstrates PROSTOX Ultra delivers significant health system cost savings and quality-of-life gains for prostate cancer patients undergoing radiation therapy.