Gene fusions: A retrospective analysis of therapies and treatments of MTB patients over 7 years.

e15183 Background: Gene fusions (GF) are less common than single nucleotide variants, amplifications, and deletions, but have been suggested to be more predictive of responses to specific molecularly targeted therapies than other types of molecular alterations. We reviewed our institutional trends for overall survival in our molecular tumor board database based on the receipt of molecularly targeted therapy. Methods: We identified patients with non-hematologic malignancies and gene fusions (GF) identified by DNA based next generation sequencing (NGS) and reviewed by the Inova Schar Cancer Institute Molecular Tumor Board (ISCI MTB) between March 1, 2016 and March 1, 2023. GFs were confirmed by re-evaluation of next generation sequencing, and we determined the number of patients who received molecularly targeted therapy (RTT) specific for the GF. We evaluated overall survival (OS) in the RTT cohort and in the cohort that did not receive targeted therapy (NTT). TMPRSS fusions in prostate cancer were excluded from this analysis. Results: There were 93 patients with gene fusions in advanced staged cancers that met study criteria. Twenty-three were lost to follow up, transferred care outside ISCI, or enrolled in hospice. Of 70 stage IV patients reviewed, thirty-seven were found to have received GF targeted therapy. OS for all patients was 28.5 months. Patients in the RTT cohort had a median OS of 45 months and patients in the NTT cohort had an OS of 26.8 months (p-value = 0.16, Log-rank test). Conclusions: Targeted therapy in solid tumors with gene fusions is associated with prolonged overall survival. It is critical for MTBs to use NGS platforms that identify GF. Further studies examining OS and GF are warranted. [Table: see text]