Abstract
INTRODUCTION: We describe the results of an exploratory analysis performed on the first head-to-head study (JapicCTI-194611) comparing two different intravenous (IV) neurokinin 1 (NK(1)) receptor antagonists, fosnetupitant and fosaprepitant, in combination with palonosetron (PALO) and dexamethasone (DEX) for the prevention of highly emetogenic chemotherapy (HEC)-induced nausea and vomiting (CINV). This analysis was performed to validate the findings of the primary analysis (previously published) utilizing a last observation carried forward (LOCF) approach for missing values for the efficacy endpoint of complete response (no emetic event and no rescue medication), while also evaluating the time periods encompassing the 0-168-hour (h) "extended overall phase" interval. METHODS: Patients scheduled to receive cisplatin-based chemotherapy were randomized 1:1 to fosnetupitant 235 mg or fosaprepitant 150 mg in combination with PALO 0.75 mg and DEX. Complete response rates were calculated and compared (stratified by age category and sex with a Mantel-Haenszel test) during the study's primary overall phase (0-120 h) and during additional time intervals of interest [acute (0-24 h), delayed (24-120 h), extended delayed (> 24-168 h), beyond delayed (120-168 h), and extended overall (0-168 h)]. RESULTS: A total of 785 patients were included (fosnetupitant N = 392, fosaprepitant N = 393). Complete response rates were numerically higher for fosnetupitant versus fosaprepitant for all time intervals and statistically significant for the extended overall phase. Complete response rates for fosnetupitant versus fosaprepitant during the overall, acute, delayed, extended delayed, beyond delayed, and extended overall phases were 75.5% vs. 71.0% (p = 0.1530), 93.9% vs. 92.6% (p = 0.4832), 77.0% vs. 72.8% (p = 0.1682), 74.7% vs. 68.4% (p = 0.0506), 86.7% vs. 81.7% (p = 0.0523), and 73.5% vs. 66.9% (p = 0.0450), respectively. CONCLUSION: In this exploratory analysis, fosnetupitant appeared to be more effective than fosaprepitant in preventing CINV associated with cisplatin-based HEC during the extended 7-day period following chemotherapy. INFOGRAPHIC.