RE: Great OBD CiRT Q+A on Presision Medicine website today9 Jan 2024 07:50
Can you provide any examples of how this test is useful in managing treatment with ICIs?
Tom: Understanding a patient’s likely response to ICI therapy is a fundamental benefit of using CiRT to help guide treatment planning. But there are additional compelling benefits.
Recently, we ran CiRT on a young, 34-year-old woman diagnosed with late-stage colorectal cancer that had also metastasized to the liver. Her biopsy was PD-L1 negative, and her microsatellite instability (MSI) was low, which usually means she is not even considered for ICI therapy. However, the CiRT test indicated that she had a high probability of responding to ICIs. Based on this new information, her oncologist has recommended her a second-line treatment with ICIs.
In another case, a 90-year-old female patient with recurrent squamous cell carcinoma tested positive for PD-L1 protein by IHC. She had a tumor proportion score of 90 percent, which would generally warrant ICI treatment, yet her CiRT profile returned a low probability of response. When treated with the ICI, the patient did not respond – confirming our prediction.
These are not isolated cases. In some of the most widely treated cancers, more than one in six patients with a negative PD-L1 result are still likely to respond to ICI therapy if given a chance. This means that there is another major use opportunity where CiRT can significantly impact and potentially change anti-cancer care.