A new study has confirmed that a molecular diagnostic test developed by MiraDx can predict the side effects of radiation therapy in prostate cancer patients before treatment.
MiraDx’s Prostox ultra-assay is based on microRNA single-nucleotide polymorphisms (mirSNPs) in non-coding regions of germline DNA that have previously been shown to play a role in predicting late genitourinary (GU) toxicity.
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GU toxicity typically appears three to six months or later following stereotactic body (SBRT) or conventionally fractionated (CFRT) radiation therapy in cancer patients.
US-based MiraDx’s prospective Phase III, 148-patient MIRAGE study (NCT04384770) validated Prostox ultra as a biomarker to predict late GU toxicity, using linear regression to evaluate the association between Prostox scores and late GU grade toxicity, and machine learning models to develop predictive models for acute and chronic GU toxicity
The company said the results reflect a correlation between the assay’s score and toxicity grade and helped it to identify three separate temporal radiation-induced GU toxicity profiles, notably acute only, chronic, and late.
The results of the study were published in the journal Clinical Cancer Research. According to MiraDx, the results support the potential of mirSNP-based biomarkers in independently predicting different types of toxicity risks before patients receive radiation therapy, irrespective of factors such as age or radiation delivery technique.
Looking ahead, the company stated that the findings strengthen the idea that responses to radiation toxicity are biologically unique for each patient, suggesting the future potential for personalising and improving cancer treatments through the use of genetics.
MiraDx co-founder Joanne Weidhaas said the MIRAGE study findings represented a “very important moment” in prostate cancer treatment and the broader oncology field.
“While tumour-based molecular profiling tests that inform treatment selection have contributed to improved patient outcomes, no tests based on germline genetics currently exist to identify toxicity risks to treatment.
“Prostox ultra is the first test that predicts radiation toxicity, giving patients and their physicians important information to make decisions that balance effectiveness with long-term quality of life.”
Amar Kishan, radiation oncologist at UCLA and primary investigator on the study, said that advancements in aspects such as radiation technology, treatment planning, and patient follow-up make it challenging to directly compare toxicity between older and more modern treatment approaches.
Kishan commented: “Despite these challenges, this study validated Prostox ultra as a predictive biomarker, and that a genetic predisposition to increased toxicity persists with modern, high-precision SBRT, including MRI-guided SBRT.”
“This finding reinforces Prostox ultra as a true measure of the biological response to radiation, independent of treatment era or technique that can identify the safest course of treatment to avoid toxicity.”
