NEW YORK – University of Michigan spinout Lynx Dx anticipates favorable coverage decisions in 2024 from Medicare and private payors as the firm works to secure national adoption of its urine-based molecular test to help identify which patients likely have clinically significant prostate cancer.
Spencer Heaton, chief medical officer for Lynx Dx, said that the Ann Arbor-based firm is also working to take advantage of the increased attention the company has received from healthcare providers following a recent JAMA Oncology article that describes the results of a validation study that compared the firm's MyProstateScore 2.0 (MPS2) test with other commonly used prostate cancer reflex tests. In the study, researchers from the University of Michigan reported that the MPS2 RT-qPCR assay had higher accuracy than alternative tests and the potential to reduce unnecessary biopsies while providing high sensitivity for the most clinically significant cancers.
"We do have a national commercial team focused on raising awareness and providing educational materials to clinicians and patients," Heaton said. "That team is growing and, currently, the test is available for ordering throughout the United States."
Aimed to address the lack of specificity in prostate-specific antigen (PSA) testing, the firm's urine-based molecular test is used to further screen patients who have a high PSA score to generate a risk score for the likelihood that a patient has clinically significant prostate cancer. The results are used to distinguish high-grade cancers from the indolent or slow-growing prostate cancers that are unlikely to affect patients' lives.
MPS2 is designed to help identify cancers with a Gleason score of 7 or higher or a Grade Group of 2 or higher using 18 genetic biomarkers and an algorithm that can incorporate clinical risk factors into the risk scores. The firm said that the test achieves between a 93 percent and 95 percent negative predictive value for clinically significant prostate cancer in men who have not had a prior biopsy, and it has a 98 percent to 99 percent negative predictive value in men who have a prior negative biopsy.
Arul Chinnaiyan, founder of Lynx Dx and professor of pathology and urology at Michigan Medicine, the University of Michigan's academic medical center, said that the negative predictive value is higher for cancers that are more likely to be aggressive.
"The test has a very high negative predictive value, especially for Grade Group 3 prostate cancer, which is actually the version of prostate cancer that we really wanted to detect because that, we know, tends to be aggressive," he said. "Grade Group 2, I think, can be controversial because a portion of Grade Group 2 is aggressive and a portion of Grade Group 2 is not aggressive."
He said that the test performs with a negative predictive score of 99 percent for Grade Group 3 cancers and 95 percent to 99 percent for Grade Group 2 cancers.
"If you come back negative, that means you have a very, very low chance of having high-grade disease," he said.
PSA is produced by both normal and malignant prostate cells, and patient PSA levels tend to fluctuate. While patients with prostate cancer tend to have elevated concentrations of the protein, other benign conditions such as inflammation or enlargement of the prostate can also cause elevated PSA levels, according to the National Cancer Institute.
Since 2018, the US Preventive Services Task Force has recommended that patients ages 55 to 69 decide with their physician whether to undergo periodic PSA screening for prostate cancer. Screening has a small potential benefit of reducing the chance of death from prostate cancer, but many men will have false-positive results that will lead to overtreatment and result in urinary, gastrointestinal, and sexual side effects.
The MPS2 test is the next generation of the two-gene MyProstateScore test developed by Michigan researchers in 2016 and commercially sold as a laboratory developed test. Lynx Dx launched the MPS2 test as an LDT in February 2023 out of its CLIA-certified and College of American Pathologists-accredited lab in Ann Arbor.
Chinnaiyan said that the 2.0 version of the test incorporates from the first test the TMPRSS2:ERG gene fusion that is found in most prostate cancers as well as the PCA3 long noncoding RNA. The 16 genetic targets that were added to MPS2 help to home in on high-grade prostate cancers, he said.
Lynx Dx has been offering MPS2 without charge to initial patients, although Chinnaiyan said that some insurers who have covered MPS have been reimbursing for MPS2 at the same $760 rate. He said that MPS2 is a replacement for the original MPS test.
Abhinav Sidana, an associate professor of surgery who specializes in urologic oncology at the University of Chicago, said that prostate cancer is the most common cancer in men in the US with approximately 250,000 prostate cancer diagnoses each year and 35,000 deaths. While historical screening methods have included PSA scores and digital rectal examination, healthcare providers have over the past 15 years increasingly relied on biomarkers from prostate MRI, blood tests, and urine tests to determine more accurately who needs prostate biopsies and reduce the number of missed high-grade prostate cancers.
Sidana said that blood- and urine-based tests can indicate with slightly better accuracy than prostate MRI whether a patient has clinically significant cancer. However, he tends to favor prostate MRI because it provides the location of the cancer, which can aid focal therapy. In cases where he has needed to supplement or replace MRI, Sidana said he has used the previous-generation MPS test for urine-based testing and Opko Health's 4KScore for blood-based testing.
While Sidana said that using prostate MRI along with a biomarker-based test could provide value for prostate cancer patients, he said that the cost of using both methods is often too high to be feasible.
The MPS2 test is far from the only option for testing beyond PSA results alone. Opko's US Food and Drug Administration-approved 4KScore test leverages protein biomarkers to detect prostate cancer, MDxHealth offers its SelectMDx urine-based risk assessment assay for patients with high PSA results as well as its ConfirmMDx tissue-based methylation test to identify patients with prostate cancer following a negative biopsy, while Minomic has developed its MiCheck Prostate test that uses three blood-based protein biomarkers along with clinical factors to identify which patients are at risk of aggressive prostate cancer.
Meanwhile, the prostate health index uses the results of three tests to develop a score for the likelihood of prostate cancer compared to benign conditions, and the Prostate Cancer Prevention Trial risk calculator uses a patient's PSA score with their clinical and family medical history to determine a patient's risk of prostate cancer.
Other tests are used to help monitor patients who are at elevated risk. DiaCarta and OncoAssure, for example, announced earlier this year that they formed a partnership to commercialize the OncoAssure Prostate six-gene expression RT-qPCR assay to identify aggressive disease following a prostate cancer diagnosis and the risk of recurrence following surgery.
Heaton also said that the company is performing studies to validate MPS2's performance in Black men, who are more likely to have prostate cancer and aggressive disease, as well as studying whether the test could be used to complement MRI for the detection of clinically significant prostate cancer. It is also developing a separate urine biomarker panel that could be used for active surveillance of patients who have a diagnosis of indolent prostate cancer. Lynx Dx officials also intend to study the use of urine-based biomarkers to predict cancer recurrence following focal therapy, Heaton said.
For now, he sees the potential that the availability of the MPS2 assay can help healthcare providers become more comfortable with PSA-based screening in their patients by reducing the risk that a slightly elevated PSA score alone will lead to unnecessary biopsies.
"The use of MPS2, it really does position PSA as a more valuable screening tool," he said.