BackgroundCo-administration of multiple antiemetics that inhibit several molecular pathways involved in emesis is required to optimize chemotherapy-induced nausea and vomiting (CINV) control in patients receiving highly emetogenic chemotherapy (HEC). NEPA, a fixed combination of a highly selective NK1 receptor antagonist, netupitant (300 mg), and the pharmacologically distinct 5-HT3RA, palonosetron (PALO 0.50 mg), has shown superior CINV prevention compared with PALO in cisplatin and anthracycline/cyclophosphamide-based settings. This study is the first head-to-head comparison of NEPA versus an aprepitant (APR)/granisetron (GRAN) regimen.Patients and methodsThis randomized, double-blind phase III study conducted in Asia was designed with the primary objective to demonstrate non-inferiority of a single oral dose of NEPA compared with a 3-day oral APR/GRAN regimen in chemotherapy-naïve patients receiving cisplatin-based HEC. All patients also received oral dexamethasone (DEX) on days 1–4. The primary efficacy endpoint was complete response (CR: no emesis/no rescue medication) during the overall (0–120 h) phase. Non-inferiority was defined as a lower 95% CI greater than the non-inferiority margin set at − 10%. Secondary efficacy endpoints included no emesis, no rescue medication, and no significant nausea (NSN).ResultsTreatment groups were comparable for the 828 patients analyzed: predominantly male (71%); mean age 54.5 years; ECOG 0–1 (98%); lung cancer (58%). NEPA demonstrated non-inferiority to APR/GRAN for overall CR [NEPA 73.8% versus APR/GRAN 72.4%, 95% CI (−4.5%, 7.5%)]. No emesis [NEPA 75.0% versus APR/GRAN 74.0%, 95% CI (−4.8%, 6.9%)] and NSN rates [NEPA 75.7% versus APR/GRAN 70.4%, 95% CI (−0.6%, 11.4%)] were similar between groups, but significantly more NEPA patients did not take rescue medication [NEPA 96.6% versus APR/GRAN 93.5%, 95% CI (0.2%, 6.1%)]. NEPA was well tolerated with a similar safety profile to APR/GRAN.ConclusionsIn this first study comparing NK1RA regimens and DEX, NEPA administered only on day 1 was non-inferior to a 3-day oral APR/GRAN regimen in preventing CINV associated with HEC.

Netupitant is a new, selective NK1 receptor antagonist under development for the prevention of chemotherapy-induced nausea and vomiting. Two studies were conducted to evaluate the brain receptor occupancy (RO) and disposition (ADME) of netupitant in humans. Positron emission tomography (PET) imaging with the NK1 receptor-binding–selective tracer [11C]-GR205171 was used to evaluate the brain penetration of different doses of netupitant (100, 300, and 450 mg) and to determine the NK1-RO duration. A NK1-RO of 90% or higher was achieved with all doses in the majority of the tested brain regions at Cmax, with a long duration of RO. The netupitant minimal plasma concentration predicted to achieve a NK1-RO of 90%, C90%, in the striatum was 225 ng/mL; after administration of netupitant 300 mg, concentrations exceeded the C90%. In the ADME study, a single nominal dose of [14C]-netupitant 300 mg was used to assess its disposition. Absorption was rapid and netupitant was extensively metabolized via Phase I and II hepatic metabolism. Elimination of >90% was predicted at day 29 and was principally via hepatic/biliary route (>85%) with a minor contribution of the renal route (<5%). In conclusion, these studies demonstrate that netupitant is a potent agent targeting NK1 receptors with long lasting RO. In addition, netupitant is extensively metabolized and is mainly eliminated through the hepatic/biliary route and to a lesser extent via the kidneys.

There were no clinically relevant interactions between netupitant and palonosetron, or between NEPA and oral contraceptives. The coadministration of NEPA with inhibitors or inducers of CYP3A4 may require dose adjustments. Treatments were well tolerated.

The results of these studies suggest that netupitant is a moderate inhibitor of CYP3A4 and therefore, co-administration with drugs that are substrates of CYP3A4 may require dose adjustments. Treatments were well tolerated in both studies.

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