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PreludeDx Aims for 2024 Launch of Test to Guide Radiotherapy for Early-Stage Breast Cancer


NEW YORK – With the support of recent study results and ongoing validation studies, PreludeDx is preparing to launch in the second half of this year a multi-omic test to determine which early-stage breast cancer patients could benefit from radiotherapy.

The firm's tissue-based AidaBreast genomic and proteomic test will be the California-based firm's second product on the market to help guide the use of radiation in the treatment of breast cancer patients, following its DCISionRT laboratory-developed test that is used to guide treatment of patients with ductal carcinoma in situ (DCIS) who are treated with breast-conserving surgery. The AidaBreast test would expand the firm's reach into the larger market of patients with Stage I or IIA breast cancer, and the company has plans to use the test as the foundation for a broader platform that could eventually give oncologists and surgeons guidance on a range of treatment options.

AidaBreast is used to deliver a 10-year prognostic risk assessment for patients who are treated with breast-conserving surgery without radiation therapy and predict the potential benefit of receiving radiation therapy following surgery. In a recent poster presentation at the 41st Annual Miami Breast Cancer Conference, the firm said that its retrospective analysis of 708 patients with Stage I or II breast cancer showed that the test results could be used to stratify patients into a low-risk group with a 1 percent recurrence rate with or without radiation therapy, an elevated risk group with a recurrence rate of 20 percent without radiation therapy or 13 percent with radiation therapy, and a residual risk group with a 30 percent risk of recurrence with or without radiation therapy.

PreludeDx President and CEO Dan Forche said that AidaBreast is a laboratory-developed test that combines next-generation sequencing to identify RNA expression, immunofluorescence for protein biomarkers, and algorithm-based analysis of those markers and their interactions. Like DCISionRT, the AidaBreast test uses a nonlinear algorithm to assess those biomarkers and their interactions along with clinical factors such as the size of the tumor or the patient's age.  Those clinical factors include, for example, the expected differences in estrogen and progesterone levels between a premenopausal patient younger than 50 years old compared with a 70 year-old one, he said.

The company is not sharing its proprietary list of genes and proteins while it applies for multiple US patents and has not set a price for the test, Forche said. The DCISionRT test, which has a list price of $5,995, targets the biomarkers PR, FOXA1, HER2, Ki-67, COX-2, p16, and SIAH2 along with clinical factors. That molecular test is used to guide the treatment of patients with DCIS, who have cancerous cells that line the milk ducts of the breast but have not spread to the surrounding tissue.

While Forche said that the firm is also withholding figures on the estimated accuracy of the test for publication in a future manuscript, he expressed confidence that the company's data so far indicate that the test is prognostic for 10-year local recurrence with or without radiation therapy. He said that his company has an opportunity "to bring forward the next generation of testing that will bring even more discrimination" along with the existing tools on the market to guide the use of chemotherapy and endocrine therapy.

"There's not a test out there that's been validated, that's commercially available today, that assesses and predicts radiation benefit in Stage I and Stage II patients," he said.

Exact Sciences, however, has been developing its own gene expression assay that also could be used to guide the use of radiation therapy in early-stage breast cancer patients. The firm's Profile for the Omission of Local Adjuvant Radiotherapy (POLAR) is a 16-gene expression score that the firm found is prognostic as well as predictive of which patients would benefit from radiotherapy.

Researchers also recently reported promising results in studies on the potential use of Exact's Oncotype Dx gene expression-based assay to guide the use of adjuvant radiation therapy. The assay is used to analyze the expression of 21 genes in patients with early-stage breast cancer or 12 of those genes in patients with DCIS to guide decisions on the use of chemotherapy.

PreludeDx also has not conducted any healthcare economic impact studies for AidaBreast but is planning them, Forche said. He noted that most patients with early-stage breast cancer are treated with breast-conserving surgery and radiation therapy. Previous study results indicate that radiation therapy reduces by half the risk of recurrence, but no molecular tests are available to indicate which of those patients are the most likely to benefit, he said.

"There's a tremendous amount of money spent to manage this disease," Forche said. "We know we can help with that."

Wendy Woodward, chair of the Breast Radiation Oncology department at the University of Texas MD Anderson Cancer Center and vice chair of the American Society for Radiation Oncology's science council, said that lumpectomy followed by radiation therapy has been the longtime standard-of-care for patients with early-stage invasive breast cancer. Radiation oncologists typically use data from prior phase III studies to guide decisions on which portions of the breast should be targeted by radiation and what volumes of radiation should be administered, but the trial data indicate only what percentage of patients in a population are likely to benefit from those treatments rather than provide patient-specific information.

"Any sort of a molecular or personalized predictor that really tells us 'Are you going to benefit?' and 'Is this the right thing for you as an individual?' would move the field forward," she said. "I think everyone would be excited about a well-validated assay like that."

Woodward said that the results of a validated test could also help to give patients peace of mind about their decisions whether to pursue or forgo radiation therapy.

Woodward is not connected with PreludeDx. However, she is also the co-chair of NRG Oncology's Breast Translational Science Committee, and she is working with that group on plans for a prospective clinical trial of PreludeDx's DCISionRT test.

PreludeDx said in its poster presentation that AidaBreast could help healthcare providers to de-escalate treatment for patients who have early-stage hormone receptor-positive invasive breast cancer and are unlikely to benefit from radiation as well as support decisions to proceed with radiation therapy for those who would benefit. Forche said that patients who are unlikely to benefit from radiation could undergo alternative chemotherapy regimens or mastectomy.

The company plans to publish this year a manuscript on the 708-patient study as well as the results of ongoing validation studies for AidaBreast from the US and international collaborators that would raise the firm's total population studied to more than 2,000 breast cancer patients. He expects some of those results will be published at mid-year medical conferences while others could be unveiled at future meetings.

The company is also expanding its sales force and bringing on board genomics specialists who can work in the field with specialists such as surgeons and radiation oncologists, including those who are already using DCISionRT. While DCISionRT could be used to guide treatment of a US population of about 56,000 patients with DCIS each year, Forche said Stage I and IIA breast cancer affects about 180,000 US patients each year.

"We've been very successful with DCISionRT, gained a lot of market share out there, and we continue to grow," he said.

Forche said radiation therapy benefit is a starting point for AidaBreast. The company aims in the long term to deliver in a single test analysis of whether a patient is likely to benefit from other treatment options, including endocrine therapy and chemotherapy. While other tests exist for endocrine therapy and chemotherapy, he thinks physicians want to get the information to guide treatment without having to send out samples to multiple labs. The firm is also studying other potential indications such as ductal hyperplasia, which is a precursor lesion that can progress to cancer, and further applications in guiding the treatment of DCIS patients.

The company runs its tests out of its headquarters laboratory in Laguna Hills, California, and a second laboratory that the firm set up in Harrisburg, Pennsylvania, to improve on turnaround times for tests in the Northeastern US.

Forche said that the company is focusing on the US market at first because it's easier to secure reimbursement for many specialty tests in the US market. However, the company three years ago formed a partnership with GenesisCare to make DCISionRT testing available in Australia, and it is eyeing healthcare markets in Europe.