Background:We evaluated the effect of this virtual education on knowledge, competence, and performance in oncology pharmacists who participated in a virtual symposium held during the Hematology/Oncology Pharmacy Association Annual Conference. The educational initiative reviewed the role of ADCs in HER2-positive breast cancer, current and emerging agents, and how to incorporate these agents into practice. Methods:•Learning and knowledge was objectively assessed by analyzing pre- and post-test results during the educational activity. Competence was assessed via post-activity evaluation where participants were asked to identify changes they intended to make in practice and any anticipated barriers that would hinder them from making changes.•Follow-up assessments were sent to participants 4-6 weeks after the live activity to determine retention of knowledge. Case study assessment questions were utilized to see if participants translated knowledge into practice. The follow-up assessments also inquired about changes made and actual barriers experienced in practice.•Statistical testing between pre- and post-tests and from pre-test to follow-up were conducted via chi square analysis with a priori significance set at 0.05. Results:•Improved knowledge was observed in several specific topic areas from pre- to post-test (PP=NS).•Learning, Knowledge, and Performanceo Therapy Selection based on National Guidelines 1st line (50% pre-activity vs. 93% post-activity vs. 75% follow-up)o Therapy Selection based on National Guidelines 2nd line (58% pre-activity vs. 86% post-activity vs. 75% follow-up)oToxicity Prevention and Management (53% pre-activity vs. 100% post-activity vs. 75% follow-up)• Competence and PerformanceoThe top intended practice changes were the same at follow-up as they were immediately following the activity. The percentage of those who intended to make changes compared to those actually made changes were also fairly similar.· Collaborate with others in the oncology care team to ensure appropriate and successful use of ADCs 60% à 50%· Share knowledge obtained with colleagues 53% à 50%· Incorporate the latest clinical guidelines for HER2+ breast cancer into practice 53% à 50%oMost barriers participants listed were experienced less often than anticipated. Notably, 40% of participants listed “formulary/insurance” as an anticipated barrier, but 0% reported facing this at follow-up. “Staying current with evolving clinical guidelines” was a barrier that nearly doubled at follow-up (53% to 100%). Specific changes from activity to follow-up are below.· Staying current with evolving clinical guidelines 53% à 100%· Lack of colleague knowledge about the latest safety/efficacy data 40% à 25%· Lack of time/staff to monitor/follow-up with patients about ADC toxicity 12% à25%· Lack of patient/caregiver recognizing and communicating toxicities 26% à 25%· Formulary/insurance 40% à 0%Conclusions: A virtual method of education was found to have a positive impact on knowledge and performance in oncology pharmacists, as evidenced by the improved scores in pre- and post-test polling, that was sustained at follow-up. The top changes actually made by participants of this activity involved collaborating with members of the oncology care team and to share knowledge obtained with their colleagues. However, the most frequently cited anticipated barrier in practice was “staying current with rapidly evolving guidelines”, which was actually experienced in practice by 100% of participants at follow-up. This demonstrates the ongoing need for additional education on this topic. Citation Format: Vanessa Carranza, Joan B Fowler, Susan H Gitzinger, Bryan C Taylor. Effect of virtual education on the knowledge, competence, and performance of oncology pharmacists attending a national symposium [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-65.