Background: Genomic testing (GT) is increasingly used to guide treatment in cancer care. There is considerable international variation in provider expertise and access to molecular tumor board (MTB) and therapeutics. In Ireland high quality GT is not broadly available; only 3% of patients receive treatment on a clinical trial. Our hypothesis is that increased GT would lead to enhanced treatment options and increase access to trials. Through institutional partnership between community cancer programs in Ireland and the United States (US), we offered GT and collaborative MTB review to patients with advanced cancer and observed the effect on treatment patterns. Methods: Eligible patients with metastatic solid tumors attending a single Irish community cancer unit between 2018 and 2022 were offered GT and collaborative MTB review on the COMPASS study. Testing was completed using a Foundation Medicine test reimbursed by multiple payors. Testing was performed on tumor tissue, or if not available, on circulating tumor DNA (ctDNA). Cases were presented virtually at MTB. Treatment decisions were based on MTB discussion of actionable alterations (AAs) with at least preclinical evidence of benefit, clinical trial availability, and local drug access. The primary outcome was impact of GT on treatment decision. Secondary outcomes included rate of AAs, and potential germline mutations. An exploratory objective evaluated potential matches to US-based NCI MATCH and ASCO TAPUR trials. Results: In total, 157 patients were screened and 120 enrolled on the COMPASS study. 46 (38.3%) male and 74 (61.7%) female with 25 different primary cancers. Tissue testing was performed for 79 (65.8%) patients and 35 (29.1%) had ctDNA testing. 105 (87.5%) patients had at least one AA by MTB criteria, 49 (46.7%) patients had more. Treatment decisions are outlined. 7 patients derived clinical benefit from treatment. 26 (21.7%) patients had a potential match for MATCH or TAPUR arms. MTB suggested 35 (29.1%) patients consider germline testing. 22 previously had genetic testing and 8 more had germline testing following GTB; 1 pathogenic germline mutation was identified. Conclusions: We successfully completely a transatlantic collaboration to introduce US MTB-directed care for Irish patients. The majority of patients had novel treatment options identified but drug access and clinical trial enrolment was limited by regional availability. International collaboration on precision oncology treatment trials should be prioritized.

*There was no treatment recommendation for 15 patients. **Six patients’ only treatment recommendation was a clinical trial unavailable in Ireland.