Homologous Recombination Repair Gene Alterations Are Associated with Tumor Mutational Burden and Survival of Immunotherapy.

BACKGROUND: Comprehensive genomic profiling (CGP) has become generally accepted practice in cancer care since CGP has become reimbursed by national healthcare insurance in Japan in 2019. However, its usefulness for cancer patients is insufficient for several reasons. METHODS: In an observational clinical study of FoundationOne® CDx, potential biomarkers were explored and the cause of testing failure was investigated. A total of 220 cancer patients were enrolled in the study during the period from 2018 to 2019 at Kyushu University Hospital. RESULTS: The primary tumor sites of the 220 cases were breast (115), colon (29), stomach (19), and pancreas (20). The present dataset suggested that homologous recombination repair (HRR) gene alterations were positively associated with tumor mutational burden-high (TMB-high) (p = 0.0099). A public dataset confirmed that patients with HRR gene alterations had a higher TMB and showed significantly longer survival of immunotherapy. In the present study, 18 cases failed sequencing. A lower percentage of tumor cell nuclei was the most common reason for testing failures (p = 0.037). Cases that received neoadjuvant chemotherapy before sampling tended to fail testing. CONCLUSIONS: HRR gene alterations can be a potential biomarker predicting TMB-high and a good response to immunotherapy. For successful sequencing, samples with lower percentages of tumor cell nuclei and previous neoadjuvant chemotherapy should be avoided.

Budget impact analysis of comprehensive genomic profiling for untreated advanced or recurrent solid cancers in Japan.

AIMS: In Japan, the use of comprehensive genomic profiling (CGP) is only available for cancer patients who have no standard of care (SoC), or those who have completed SoC. This may lead to missed treatment opportunities for patients with druggable alterations. In this study, we evaluated the potential impact of CGP testing before SoC on medical costs and clinical outcome in untreated patients with advanced or recurrent biliary tract cancer (BTC), non-squamous non-small cell lung cancer (NSQ-NSCLC), or colorectal cancer (CRC) in Japan between 2022 and 2026. MATERIALS AND METHODS: We constructed a decision-tree model reflecting the healthcare environment of Japan, to estimate the clinical outcome and medical costs impact of CGP testing by comparing two groups (with vs without CGP testing before SoC). The epidemiological parameters, detection rates of druggable alterations, and overall survival were collected from literature and claims databases in Japan. Treatment options selected based on druggable alterations were set in the model based on clinical experts' opinions. RESULTS: In 2026, the number of untreated patients with advanced or recurrent BTC, NSQ-NSCLC, and CRC was estimated to be 8600, 32,103, and 24,896, respectively. Compared with the group without CGP testing before SoC, CGP testing before SoC increased druggable alteration detection and treatment rate with matched therapies in all three cancer types. The medical costs per patient per month were estimated to increase with CGP testing before SoC in the three cancer types by 19,600, 2900, and 2200 JPY (145, 21, and 16 USD), respectively. LIMITATIONS: Only those druggable alterations with matched therapies were considered in the analysis model, while the potential impact of other genomic alterations provided by CGP testing was not considered. CONCLUSIONS: The present study suggested that CGP testing before SoC may improve patient outcomes in various cancer types with a limited and controllable increase in medical costs.

Clinical utility of genomic profiling of AML using paraffin-embedded bone marrow clots: HM-SCREEN-Japan 01.

Next-generation sequencing of AML has identified specific genetic mutations in AML patients. Hematologic Malignancies (HM)-SCREEN-Japan 01 is a multicenter study to detect actionable mutations using paraffin-embedded bone marrow (BM) clot specimens rather than BM fluid in AML patients for whom standard treatment has not been established. The purpose of this study is to evaluate the presence of potentially therapeutic target gene mutations in patients with newly diagnosed unfit AML and relapsed/refractory AML (R/R-AML) using BM clot specimens. In this study, 188 patients were enrolled and targeted sequencing was undertaken on DNA from 437 genes and RNA from 265 genes. High-quality DNA and RNA were obtained using BM clot specimens, with genetic alterations successfully detected in 177 patients (97.3%), and fusion transcripts in 41 patients (23.2%). The median turnaround time was 13 days. In the detection of fusion genes, not only common fusion products such as RUNX1-RUX1T1 and KMT2A rearrangements, but also NUP98 rearrangements and rare fusion genes were observed. Among 177 patients (72 with unfit AML, 105 with R/R-AML), mutations in KIT and WT1 were independent factors for overall survival (hazard ratio = 12.6 and 8.88, respectively), and patients with high variant allele frequency (≥40%) of TP53 mutations had a poor prognosis. As for the detection of actionable mutations, 38% (n = 69) of patients had useful genetic mutation (FLT3-ITD/TKD, IDH1/2, and DNMT3AR822 ) for treatment selection. Comprehensive genomic profiling using paraffin-embedded BM clot specimens successfully identified leukemic-associated genes that can be used as therapeutic targets.