MO3-6-4The first step of precision medicine with blood based genomic sequencing assay in a Japanese local university hospital

Abstract Background Guardant360® is a commercial cancer genomic sequencing assay which covers 73 cancer related genes and provides comprehensive genomic results. This assay is minimally-invasive because it requires a simple blood specimen, and it might help us to choose matched treatments for the patients without invasive biopsy. The assay was introduced to our hospital in November 2018. We summarize the clinical utility of the results provided by Guardant360® in a Japanese local university hospital. Methods We examined seven cases who had advanced solid cancers including small cell lung cancer (n = 1), cervical cell cancer (n = 1), ovarian cancer (n = 1), breast cancer (n = 3), gallbladder cancer (n = 1). These patients had been already treated with at least one line of chemotherapy. Physician’s opinion based on the result of Guardant360® was discussed in the expert meeting before it was provided to each patient. Results Mean age of all patients was 66.3 years old (range; 48-76). All but one patient (85.7%) harbored actionable aberrations and the mean of detected actionable aberrations was 4.3 (range; 0-7). MSI-High was not detected in any patients. Based on these results, two patients (28.6%) were offered new therapeutic indications which were already approved in Japan, and another patient (14.3%) was suggested to be a candidate of an ongoing clinical trial of the gene specific molecular targeted therapy. Furthermore, another patient (14.3%) was identified an incidental secondary finding which was associated with the American College of Medical Genetics and Genomics guideline and the patient was recommended to have genetic counselling and further examination. Conclusion In the first four months, almost one third of patients reached new treatment strategy using approved drug, and another patients offered a clinical trial based on the results of Guardant360®. Because the treatment efficacy based on the result is still unknown, further data accumulation is still needed.