Abstract Introduction To inform funding strategies for research in metastatic breast cancer (MBC), knowledge of the current research landscape and identification of potential gap areas requiring additional research are essential. In 2014, the Metastatic Breast Cancer Alliance (MBCA) published an analysis that showed that between 2000 and 2013, only 7% of all funds for breast cancer research were devoted to metastasis. As more people are living with MBC, addressing research priorities for those living with the disease is important, as is understanding gaps in the current funding landscape of MBC research to appropriately target investment. Methods A collaborative effort between funders and patients was undertaken to analyze breast cancer projects funded between 2014 and 2020 from the International Cancer Research Partnership database, the Health Resource Alliance database, and MBCA members, representing grants from 83 non-profit organizations worldwide. Project titles, abstracts, and classifications of these grants were extracted from these databases. Next, to identify research projects in the databases that are related to metastasis, a classification tool that uses a machine learning algorithm was built, trained on manually coded grants from the 2000-2013 analysis, and validated by expert coders. Projects were then coded according to a pre-established metastasis classification policy to categories such as type of research (e.g., treatment), genes or proteins studied, site of metastasis, breast cancer subtype, and patient priority questions. In terms of the latter, MBCA members living with MBC were surveyed about research priorities. Member advocates ranked survey questions according to highest patient priority, and these were converted to language that could be queried with the tool. Results Investment in MBC research nearly doubled from 2014 to 2020. Research into understanding and overcoming treatment resistance, which was the highest patient priority question, increased from 15% in 2014 to 26% of the MBC portfolio in 2020; this was a statistically significant increase above the rate of inflation. In terms of treatment resistance according to subtype, the highest number of projects focused on triple-negative MBC (>300). By contrast, < 20 projects were focused on overcoming treatment resistance in metastatic invasive lobular breast cancer. Of the six categories evaluated (e.g. biology and detection/diagnosis/prognosis), the largest increase in investment was for treatments. Discussion The coding tool allows for ongoing complex queries such as identification of funded research relevant to areas identified as important by MBC advocates (Table) and provides a funders’ ‘dashboard’ to identify gap areas in need of further research funding. This collaborative effort between funders and patient advocates, and the resulting current and future analyses, can be used to focus advocacy efforts to drive research funding of priorities and understudied areas of MBC. Despite the increase in funding, the investment in metastatic research–the primary cause of death from breast cancer–remains insufficient. Table. Research Priorities of MBC Patient Advocates Citation Format: Margaret Flowers, Teri Pollastro, Kari Wojtanik, Katherine McKenzie, Kimberly Badovinac, Medha Deoras-Sutliff, Lynne Davies. Analysis of Trends in Funding of Metastatic Breast Cancer Research [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-05-10.