OBJECTIVES: This study assesses frequency of CINV events and resource utilization in patients treated with AC for solid cancers METHODS: The study evaluated a randomly selected cohort of patients from Inovalon’s MOREResearch Edition claims database that includes longitudinal data from US health plans. Patients who received AC regimens on first day of each cycle in first line of therapy during last six months of 2013 were included. Total CINV events and CINV related and total hospital/ER visits were captured for cycles of interest in first line and were analyzed using chi-square to determine statistical differences between patients on NK-1 regimens and non-NK-1 regimens.  RESULTS: The study cohort consisted of 353 patients, 97% female, 60% with Commercial insurance, and 95% with breast cancer, with mean age of 53.1 and Charlson comorbidity score of 6.0.  NK-1 based CINV regimens were utilized in 73% of the patients in the first chemotherapy cycle.   Rescue anti-emetics were used by 53% of patients on NK-1 regimens versus 60% of patients on non NK-1 regimens.  Frequency of CINV events was 41% for NK-1 versus 45% for the non NK-1 group.   Frequency of CINV related ER visits was 5% in the NK-1 group versus 12% in the non NK-1 group, p=0.03.  CINV related hospitalizations were 3% in the NK-1 group versus 4% in the non-NK-1 group.  Total ER visits were lower in the NK-1 group compared to the non NK-1 group, 12% versus 19%; total hospitalizations were also lower in the NK-1 group compared to the non NK-1 group, 8% versus 13%. CONCLUSIONS: For patients on highly emetogenic AC based chemotherapy regimens, NK-1 treatments result in decreased rates of CINV events and resource utilization, with CINV related ER visits statistically lower.  Further studies are warranted to determine if results are generalizable to other cancer regimens and diagnoses.