NEW YORK – Burning Rock Biotech said this week that it has launched its first assay for minimal residual disease detection and is preparing to follow that up with its six-cancer early detection test as soon as China's current COVID-19 lockdown eases.
Speaking on a call discussing the company's 2021 financial results this week, Burning Rock CEO Yusheng Han said that the firm has partner hospitals established to begin implementing the six-cancer screening assay, but it won't be able to begin the process until COVID-19 restrictions are lifted.
In the meantime, its MRD assay, BrPROPHET, became available earlier this month with initial market feedback looking "quite positive."
Important validation data for both tests are slated for presentation at the upcoming annual meeting of the American Association for Cancer Research, and Burning Rock Chief Operating Officer Shannon Chuai previewed some of the top-line results during the call this week.
Reviewing Burning Rock's early detection product development map, Chuai highlighted two major updates. First, the firm has finalized plans for a 10,000-patient prospective interventional study in an intended use population. "This study, which is now named PREVENT, has obtained approval from the Human Genetic Resources Administration in China and is now ready to start accrual," Chuai said.
Secondly, the Chinese company has completed its first data readout on its second generation of the test, a nine-cancer product, from the case-control pilot validation study PROMISE.
"The performance so far looks quite promising," Chuai said. Statistics are still being summarized and finalized, so she said Burning Rock can't share more details now, but the firm is submitting the results for presentation at the European Society of Medical Oncology meeting later this year.
Burning Rock also expected to have data from a larger case-control cohort study, called PREDICT, this year but due to increased COVID-19 restrictions in China, this has been delayed. Initial enrollment should be complete within a few months, with the first data now reading out in 2023, Chuai said.
In the meantime, the company is slated to present some early data on the six-cancer test next month at the upcoming AACR conference. This includes demonstration of a limit of detection between 0.02 percent and 0.11 percent mutant allele frequency across different cancer types for its ELSA-seq technology.
Although the six-cancer assay will be launched initially as a central lab test, Burning Rock is eventually hoping to commercialize it as a disseminated kit for in-hospital use. Early conversations with China's National Medical Products Administration have been encouraging, according to company officials.
Regarding the firm's newly launched MRD test, Chuai said that Burning Rock believes that its commercialization comes at an opportune moment. As little as a year or two ago, Chinese physicians were much more skeptical about the utility of genomic MRD testing.
But that has changed rapidly, Chuai said, highlighting a 2021 consensus statement by Chinese oncologists endorsing MRD testing for relapse-risk prediction in early-stage NSCLC.
Citing a recent review article on MRD applications in solid tumors published by a group of Stanford oncologists, Chuai said that the field has been able to divide MRD applications into two main categories.
"The first one is the so-called landmark analysis, where MRD status is assessed right after operation or other curative therapy for cancer patients, where it serves as a highly significant predictor of prognosis."
She called the utility data that has emerged from studies of assays from US companies like Natera in this scenario "nearly unanimous," and said this is increasingly being recognized by Chinese practitioners as well.
A second application proposes surveilling patients longitudinally in order to flag relapse events ahead of time, before radiological or clinical signs. The hope there is that an earlier intervention can lead to better survival. But this value is viewed as much less established than landmark prognostic testing, not only among Chinese clinicians but globally, Chuai said, citing recent conflicting conclusions in the published literature driving ongoing debate.
Evidence that landmark testing can be not only prognostic but also predictive of adjuvant therapy response is also emerging, Chuai said, but more evidence needs to be generated before a full consensus can be reached on that expanded utility.
Despite that uncertainly, the potential promise is exciting enough that Burning Rock has begun to actively collaborate with Chinese clinicians to validate its technology and prove utility.
The firm has two MRD data presentations slated for the upcoming AACR meeting, one in lung cancer and another in colorectal cancer.
Chuai said the first study compared the firm's BrPROPHET, a personalized MRD approach similar to that used by US firms like Natera, Inivata, and ArcherDx, with a fixed liquid biopsy panel.
In an analysis of a subgroup of relapsed patients, both the fixed panel and BrPROPHET generated highly significant prognostic predictions, but the personalized MRD was more sensitive, identifying more MRD-positive patients at the landmark test time point. Investigators also saw a higher relapse rate among MRD-negative patients.
Although the firm isn't presenting full study results at the meeting, Chuai added that the total cohort included approximately 200 MRD-negative patients, more than 95 percent of whom remained recurrence free at 12 months.
The firm's colorectal cancer study was in a smaller cohort, but showed similar results, with BrPROPHET demonstrating greater performance than a fixed-panel approach.
According to Han, Burning Rock is still in the early stages of determining the impact of its MRD test launch earlier this month, but he said the response from the doctors has been positive.
"The educational situation nowadays is different from what we saw two years ago," he said. When the firm talked to oncologists at that point, they questioned the value of MRD over existing methods to determine whether surgery was successful or not.
"Now they would not say that, because they have been influenced by the global opinion leaders, and they have noted that MRD is a very useful tool for them in early-stage cancer patients."