Different Genomic Clusters Impact on Responses in Advanced Biliary Tract Cancer Treated with Cisplatin Plus Gemcitabine Plus Durvalumab

Background: The results reported in the TOPAZ-1 phase III trial led to the approval of the combination of cisplatin and gemcitabine with durvalumab as the new first-line standard of care for patients with locally advanced or metastatic cholangiocarcinoma. Objective: We performed a clustering analysis to classify patients into different groups based on their mutation profile, correlating the results of the analysis with clinical outcomes. Methods: We selected 51 patients with cholangiocarcinoma who were treated with the combination of chemotherapy and durvalumab and who were screened using the next-generation sequencing-based FoundationOne gene panel. We conducted mutation-based clustering of tumors and a survival analysis. Results: Three main clusters were identified. Cluster 1 is mostly characterized by mutations in genes belonging to the chromatin modification pathway, altered in 100% of patients. Cluster 2 is characterized by the alteration of several pathways, among which DNA damage control, chromatin modification, RTK/RAS, cell-cycle apoptosis, TP53, and PI3K were the most affected. Finally, most altered pathways in cluster 3 were RTK/RAS and cell-cycle apoptosis. Overall response rate was 4/13 (31%), 12/24 (50%), and 0/10 (0%) in cluster 1, cluster 2, and cluster 3, respectively, and the difference between the three clusters was statistically significant (p = 0.0188). Conclusions: By grouping patients into three clusters with distinct molecular and genomic alterations, our analysis showed that patients included in cluster 2 had higher overall response rates, whereas patients included in cluster 3 had no objective response. Further investigations on larger and external cohorts are needed in order to validate our results.