Dual NK-1/5-HT3 Blockade Eases CINV in Moderately Emetogenic Chemotherapy

Chemotherapy-induced nausea and vomiting (CINV) remains a significant clinical hurdle for patients undergoing cancer treatment, particularly in the delayed phase occurring 24 to 120 hours after chemotherapy. At the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, researchers presented results from the phase 3 PROTECT trial, which may offer a more effective and simplified management strategy for patients receiving moderately emetogenic chemotherapy (MEC).

The study, led by Li Zhang, MD, of the Sun Yat-Sen University Cancer Center, evaluated a fixed-dose intravenous combination known as HR20013. This combination pairs fosrolapitant, a prodrug of the long-acting NK-1 receptor antagonist rolapitant (Varubi), with palonosetron (Aloxi), a second-generation 5-HT3 receptor antagonist. For oncology nurses, this dual long-acting blockade represents a shift toward more robust prophylaxis for a patient population where 30% to 40% currently still experience delayed vomiting despite standard treatments.

What were the complete responses following CINV treatment with HR20013?

The experimental regimen met both its primary and key secondary end points with high statistical significance. In the delayed phase, the complete response rate was 79.0% for the HR20013 group compared to 61.4% for the control group (P < .001). This benefit extended to the overall phase, where 75.6% of patients in the HR20013 arm achieved a complete response versus 59.9% in the palonosetron-only arm (P < .001). Even in the acute phase (0-24 hours), the combination showed a slight but significant advantage (92.5% vs. 86.1%, respectively; P = .005).

The benefit of HR20013 was consistent across nearly all clinically relevant subgroups. This included analysis by sex, age (under 55 vs. 55 and older), and tumor type. Specifically, patients with gastric, esophageal, or gastroesophageal junction cancers saw a 30.8% difference in delayed-phase complete response favoring the study arm.

Beyond the primary metrics, HR20013 improved several other patient-centric end points. Rates of no emesis in the delayed phase were significantly higher with the dual-blockade (83.0% vs. 63.1%, respectively), and fewer patients in the HR20013 group required rescue medications (91.7% required no rescue meds vs. 84.9% in the control group).

What was the design of the phase 3 PROTECT study?

The PROTECT trial was a multicenter, randomized, double-blind, active-controlled phase 3 study. It enrolled 706 chemotherapy-naïve patients with solid tumors who were scheduled to receive single-day MEC. Participants were randomized 1:1 to receive either the HR20013 combination plus dexamethasone or a control regimen of palonosetron plus dexamethasone.

The primary end point was complete response (CR) during the delayed phase, defined as no emesis and no rescue medication use between 24 and 120 hours post-chemotherapy. Key secondary end points included CR during the overall phase (0-120 hours) and patient-reported outcomes regarding the impact of CINV on daily life.

How can oncology nurses improve quality of life and safety with HR20013 treatment?

From an oncology nursing perspective, the impact of CINV on a patient's daily functioning is a critical metric of success. The PROTECT trial utilized patient-reported outcomes (PRO) to measure this impact. A higher proportion of patients in the HR20013 group reported no impact on daily life, particularly regarding the vomiting domain in the delayed phase (90.2% vs. 75.9%, respectively; P < .001). The time to treatment failure — a composite of emesis, rescue medication use, or study withdrawal — also significantly favored the combination therapy (HR, 0.52; P < .001).

The safety profile of the fixed-dose combination was found to be consistent with the known effects of its individual components. Overall treatment-emergent adverse events (TEAEs) occurred in 87.3% of the HR20013 group and 87.7% of the control group. Grade 3 or higher treatment-related adverse events (TRAEs) were uncommon, occurring in only 1.2% of patients receiving the study drug.

The most frequent TRAEs (at least 2%) associated with HR20013 included: constipation (8.9%), hypertriglyceridemia (4.0%), hiccups (3.5%), and increased ALT (2.3%).

Nursing staff should monitor for these common side effects, though the data suggests they are generally manageable and rarely lead to treatment discontinuation.

The results of the PROTECT trial support the use of dual long-acting NK-1/5-HT3 blockade as a superior antiemetic strategy for patients receiving MEC. By integrating 2 powerful mechanisms into a single intravenous fixed-dose regimen, clinicians can simplify the prophylactic process while significantly improving the control of delayed emesis. As oncology nursing continues to prioritize patient quality of life, these findings offer a validated tool to help patients maintain their daily functioning throughout their chemotherapy journey.

Reference

1. Zhang L, Li Y, Wang D, et al. Randomized, double-blind phase 3 trial of the fixed-dose combination fosrolapitant/palonosetron (HR20013) plus dexamethasone for prevention of nausea and vomiting in patients receiving moderately emetogenic chemotherapy (PROTECT). Presented at: 2026 ASCO Annual Meeting; May 29-June 2, 2026; Chicago, IL.