Genomeweb reports on the recent Pathfinder-2 results by Grail Bio. Here are my highlights:
Grail on Wednesday reported positive top-line performance and safety results from its Pathfinder 2 study, finding that adding its multi-cancer early detection (MCED) test to standard-of-care cancer screening showed substantially greater additional cancer detection than in its original Pathfinder study.
An MCED assay intends to finds early signs of cancer, in the case of Galleri, for a collection of 40-50 different cancer types based on the methylation profiles of the short bits of DNA that flow in the bloodstream. Given that the presence or absence of methylation in CpGs (Cs followed by Gs in the sequence) informs of the tissue/cell type of the cell containing that DNA, if there is an anomalous pattern of cell-free DNA (cfDNA) in the blood, Galleri can give a prediction of a cancer growth in one of the organs in the body (e.g. lung, or breast, or colon, etc). The way Galleri was constructed was to assay lots of cases and controls for the same type of methylation detection method, then build a classifier that is able to tell if the next sample is a non-cancerous profile, similar to the controls, or a cancer profile, like the ones previously observed. The Pathfinder-2 study has accumulated data on how well this assay is performing in the real world.
The firm's stock price was up 12 percent to $47.13 per share in mid-day trading on the Nasdaq after the news was announced Wednesday morning.
Pathfinder 2 is a prospective, multi-center, interventional study intended to evaluate the safety and performance of the blood-based Galleri test in 35,000 people aged 50 and older who are eligible for guideline-recommended cancer screening in the US. According to Grail, the study aims to evaluate the safety and effectiveness of Galleri based on the number and type of diagnostic evaluations performed in participants who receive a "cancer signal detected" test result and to evaluate the performance of Galleri across multiple measures, including positive predictive value, negative predictive value, sensitivity, specificity, and cancer signal origin prediction accuracy.
The secondary objectives include the utilization of guideline-recommended cancer screening procedures after the use of Galleri and participant-reported outcomes at several time points, such as an assessment of participants' anxiety and satisfaction with Galleri.
This second part, the effect of the Galleri results on cancer screening procedures, which is often called “clinical utility”, is one crucial measuring stick which will determine how quickly and how deeply this type of MCED assays are adopted in developed countries. There has been a lot of talk about the difficulty to proceed from an MCED diagnosis in the current medical field, and a lot of people propose instead to concentrate on MRD assays (Minimal Residual Disease detection) which are found to be easy to “implement” on current medical settings. The problem with MRD is that, in most cases, we’ve allowed the cancer to grow, sometimes even become metastatic, before we apply diagnostic and therapeutic tools to try to overcome it. On the other hand, MCED assays that are performed on the majority of the risk population in a screening setting, have the promise of being able to catch the tumour growth early enough so that the treatments are going to be less damaging to the patient and have a much better outcome.
Strategic Positioning
Below I’ll discuss why this Pathfinder 2 results are important and how to strategically position a biotech portfolio around them.