Advancing Cancer Detection With the ASCEND Trial: Key Objectives and Rationale

Transcript:

Jon O. Ebbert, MD: …Maybe you could talk a little bit about the rationale, design and key objectives for the ongoing ASCEND trial.

Tom Beer, MD, FACP: There are actually 2 studies, PRE-ASCEND and then ASCEND, and I’ll lump them together. These are critical case-control studies where samples are collected from patients with a known cancer diagnosis and also from so-called control participants without known cancer who were thought to be healthy but are likely of similar age and so on and so forth. Those samples are critical to the development of MCED tests. So that is the sample set that is used to analyze the 3 and 4 biomarker classes that serve as the backbone of the MCED [multicancer early detection] test from Exact Sciences and determine the performance of the candidate’s biomarkers, which allows us to calibrate the cutoffs and really design the algorithm for making a cancer or no cancer call. The ASCEND-2 study, which is the most recent study, is the largest of these case control studies. It carefully collects the specimens prospectively, either immediately following the diagnosis of cancer or in some cases even before [the diagnosis].

There are a handful of cancers that are often diagnosed and treated at the same time as a surgical procedure, so it wouldn’t be possible to collect a sample following a diagnosis from a patient who still has some cancer cells in their body. So these are samples collected before treatments are begun. The current study is looking at more than 20 cancer types at a broad range of stages and will serve as the final sample set for us to finalize the design and lock down essentially the design of the Exact Science MCED test before we launch prospective studies. I might also comment on the data I reported to date from these efforts, and these are largely from the PRE-ASCEND component of the studies. These were reported in the fall of 2022 at the ESMO [European Society for Medical Oncology] meeting and then also at the special meeting of the AACR [American Association for Cancer Research].

What we saw in that study was that the combined sensitivity of the MCED test when using 4 biomarker classes was 62.4%. That’s across all cancers and all cancer stages. A 3 biomarker class test achieved a somewhat lower sensitivity at 55%. That sounds like a relatively small difference, but much of that difference accrued in stage I and stage II cancers where you really want these tests to perform best. So the 4 biomarker class test really had the best possible chance of detecting early-stage cancers. Indeed, the test achieved a 40.5% sensitivity for the combination of stage I and stage II cancers examined. I would want to caution our audience that performance in a case control study is not the same as performance in a prospective interventional trial.

So we’re very encouraged by these results, but we’ll be looking to replicate them in ASCEND-2, the current case-control study, and then examine them again in a prospective intended use indication, where we would expect somewhat lower sensitivity than one would expect in a case-control setting.

Transcript is AI generated and edited for readability.