3157 Background: The ROME trial (NCT04591431) investigates the efficacy of a tailored treatment (TT), driven by extensive genomic tests and Molecular Tumor Board (MTB) evaluation, compared to standard treatment (SoC) in patients (pts) with refractory metastatic cancer. Here we report the prevalence of actionable variants identified and the personalized treatment received by the patients enrolled. Methods: A centralized extensive NGS test (FoundationOne CDx and Liquid CDx) was performed on both tissue and blood samples. Pts with at least one potentially targetable alteration matched to the available drugs were discussed at the MTB. MTB evaluation criteria were: genomic variant type, tumor mutational burden (TMB), VAF, availability of preclinical or clinical data of efficacy and patients’ clinical characteristics. COSMIC, ClinVar, OncoKB and VarSome datasets were used to evaluate the clinical actionability of genomic alterations. MTB indications were: randomization to TT vs SoC, screening failure (SF), or indication to other trial/access to the drug. Results: From November 2020 to August 2023, 1794 pts were screened. A total of 127 weekly MTB meetings were conducted and 899 cases were discussed (7 cases/meeting on average). After MTB discussion, a targetable genomic alteration was identified in 425 pts, who received an indication to be randomized. MTB assigned ICIs to 190 pts (155 to ipilimumab plus nivolumab; 8 to nivolumab) due to high (≥10 mut/mb) TMB. 234 pts had indications to target therapy: 86 pts (37%) to PI3K/AKT/mTOR inhibitors(i), 59 (25%) anti-HER2 agents, 34 (15%) FGFRi, 31 (13%) BRAF/MEKi, 7 (3%) PARPi, 5 (2%) CDK4/6i, 4 (2%) ALKi, 2 (>1%) NTRKi, 2 (>1%) RETi, 2 (>1%) Hedgehog-i, 1 (>1%) JAKi, 1 (>1%) MEKi. 27 pts had indication to ICIs plus target therapy combinations. Additionally, 150 pts with potentially hereditary variants were addressed to genetic counselling and germline testing. Finally, according to the genomic evaluation, 63 pts were referred by MTB to other clinical trial even if considered SF for the ROME trial, 34 patients received from the MTB a modification of the initially proposed standard therapy and 4 had both suggestions. Overall, 652 pts (36%) received an indication following NGS test and MTB evaluation. Conclusions: Our study provides evidence that MTB discussion of comprehensive genomic profiling data identifies a personalized treatment in a large (36%) fraction of patients, thus outperforming the traditional histological approach. Clinical trial information: NCT04591431 .