Abstract RF01-08: A randomized, open-label phase III trial Evaluating Low-Dose Vs standard-dose Olanzapine with triple Antiemetic therapy for Prevention of highly emetogenic chemotherapy- induced Nausea and vomiting in solid tumors (OLAnzaPiNE)

Abstract Background Chemotherapy induced nausea and vomiting (CINV) is a major adverse event for cancer patients. Olanzapine (OLZ) in standard 10 mg dose along with triple antiemetics (TAE), has shown effectiveness in treating CINV with highly emetogenic chemotherapy (HEC), however, significant day time somnolence (DTS) precludes its widespread use. Steroids related side effects are another major concern. Hence, a lower dose of OLZ, with single dose (SD) steroid use is worth exploring in a randomized fashion. Methods Solid tumors planned for anthracycline-cyclophosphamide & high-dose cisplatin chemotherapy was randomized (1:1) to receive either 10mg OLZ (standard arm) or 2.5mg (experimental arm) till day 4 with TAE regimen [5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, dexamethasone (SD, without delayed doses), and neurokinin-1 (NK1) receptor antagonists] in both arms. Primary objective was to evaluate Complete control rate (CCR) defined as proportion of subjects with no emetic episodes (EE), no use of rescue medications (RM), no or mild nausea assessed in overall phase (OP) =0-120 hours(h) in both groups. Secondary objectives were to compare two groups for the CCR in acute(AP) and delayed phase(DP);Complete response rate (CRR)=no EE and no use of RM in AP(0- 24h), DP(25-120h) and OP; Total control rate(TCR)= no EE, no use of RM, and no nausea) in AP, DP, OP; Time to treatment failure(TTF), defined as mean duration from chemotherapy initiation to first episode of nausea, EE, use of RM; Incidence of significant daytime somnolence(DTS).Tertiary objectives were effect on appetite loss. Subjects maintained a daily record of nausea, EE, RM use with the severity graded on a four-category scale. Statistical analysis CCR, CRR, TCR are given in counts and proportions. Occurrence of nausea, EE, DTS and their grades were compared using Chi-square test. Results A total of 275 subjects were enrolled, among them 267 were analyzable, inclusive of 132 subjects in 2.5mg and135 in 10mg arms with well-balanced baseline characteristics (Table 1) Proportion of patients with CCR in OP (Primary end point) in 2.5mg vs. 10mg arms were, 44.7 % vs. 43.7 % (P = 0.87) respectively. CCR in 2.5mg vs. 10mg arms in AP, DP were 50% vs. 48.9%(p=0.856) and 50.8% vs. 58.5% (P=0.203) respectively. CRR in 2.5mg vs. 10mg in AP, DP and OP were 56.1% vs. 57 % (P=0.872), 55.3% vs. 63% (P = 0.203), and 50.8 % vs. 51.1% (P=0.954), respectively. TCR in2.5mg vs. 10mg in AP, DP, and OP were25% vs. 23 % (P=0.697), 20.5% vs. 22% (P = 0.725), and 13.6 % vs. 15.6% (P=0.657), respectively. Subjects receiving 2.5 mg as compared with those receiving 10 mg, had statistically significant decreased DTS on overall grades 65.2%vs 89.6% vs. (p < 0.001); severe grade DTS was more on day1 i.e., 4.5%vs. 40% (p < 0.001) and although successively reduced from day 2-5 in both the arms, however, 2.5 mg fared better on all the days (table 1). No statistically significant effect of reduced appetite noted in 2.5mg vs. 10mg i.e., 17.4% vs. 24.4 %(p=0.208) Conclusion Low dose olanzapine (2.5mg) is non inferior to 10mg olanzapine in controlling CINV without requirement of delayed steroids, and is superior with respect to DTS (all days, all grades, severe grades) in subjects receiving HEC. This merits wide recognition as a new steroid sparing antiemetic regimen of choice with HEC. Demographic data, Clinical characteristics and Outcomes Citation Format: Jyoti Bajpai, Venkatesh Kapu, Sushmita Rath, Sravan Kumar, Anbarasan Sekar, Srikanth Anne, Akash Pawar, Sujay Srinivas, Prabhat Bhargava, Seema Gulia, Rajiv Sarin, Rajendra Badwe, Sudeep Gupta. A randomized, open-label phase III trial Evaluating Low-Dose Vs standard-dose Olanzapine with triple Antiemetic therapy for Prevention of highly emetogenic chemotherapy- induced Nausea and vomiting in solid tumors (OLAnzaPiNE) [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 RF01-08.