Nausea and emesis is the most common inauspicious consequence of chemotherapy 1. It is besides regarded by patients as one of the most unpleasant and refering inauspicious effects of chemotherapy, and is a major ground for patients abandoning chemotherapy intervention 2,3. The incidence and badness of chemotherapy induced sickness and emesis ( CINV ) is dependent on the type of chemotherapy and patient specific hazard factors. Patient specific hazard factors include female gender, age 50 old ages, history of low intoxicants intake, history of old chemotherapy-induced vomit, history of gesture illness, and history of vomit during a past gestation 4. CINV is categorized into 4 phases based on the timing of the sickness and emesis from chemotherapy: ague ( 24 hours post intervention ; most common ) , delayed ( 1-7 yearss post intervention ) , prevenient ( before chemotherapy ) , and discovery ( CINV despite preventive therapy ) CINV 4. CINV involves the activation of the chemoreceptor trigger zone in the myelin, intellectual cerebral mantle, and GI piece of land by chemotherapeutic agents, that consequences in the co-ordinated secretory and musculus contractions that drives emesis 1. Serotonin receptor subtype 3 ( 5-HT3 ) in the CNS and GI piece of land are one of the receptors involved in this procedure, and is the mark of antiemetic agents that belong in the 5-HT3 receptor antagonist category 4.
Although first coevals 5-HT3 receptor adversaries ( Internet Explorer. granisetron, ondasetron, dolasetron ) are every bit effectual in forestalling acute CINV, the same can non be said about their function in delayed CINV 2. In fact, a systematic reappraisal did non happen sufficient grounds for the usage of first coevals 5-HT3 receptor adversaries to be used beyond 24 hours after chemotherapy for the bar of delayed CINV 5.
Palonosetron ( Aloxi )
Palonosetron, sold under the trade name name Aloxi, was late approved by Health Canada for the bar of chemotherapy induced ague and delayed sickness and purging 8. The Notice of Compliance for Aloxi was issued on March 14, 2012.
Palonosetron is a 2nd coevals 5-HT3 receptor adversary with a higher binding affinity, authority, and longer half life ( ~40 hours vs. 9 hours ) than all first coevals agents 6. The adhering affinity of Palonosetron is at least 30 crease higher than first coevals 5-HT3 receptor adversaries, which may be explained by its allosteric binding and positive cooperativity versus simple bimolecular binding for the older agents 2,7. Molecular surveies has farther shown that palonosetron triggers 5-HT3 receptor internalisation, which prolongs its repressive consequence on the receptor 7.
Oral bioavailability of palonosetron is about 97 % , and is non affected by nutrient consumption8. It has a volume of distribution of 8.3 L/kg, and is 62 % protein edge. Palonosetron is metabolized by CYP2D6, CYP3A4, and CYP1A2. The path of riddance is primary in the piss, with 42 % as unchanged drug.
There is no dosage accommodation required for palonosetron for renally and hepatically impaired patients 8,9. It & amp ; acirc ; ˆ™s effects on gestation is mostly unknown, but It is non recommended in lactation due to the deficiency of back uping informations in that patient population. Animal surveies did non happen foetal hazard but the effects on pregnant adult females are mostly unknown. Palonosetron is categorized under gestation hazard factor B, and should be used in gestation merely when needed.
Health Canada Indications and Supporting Evidence
The bar of ague and delayed sickness and emesis associated with reasonably emetogenic malignant neoplastic disease chemotherapy 8.
In a combined analysis of two stage III randomized controlled trails with 1132 entire patients, individual dosage IV palonosetron 0.25mg and 0.75mg administered 30 proceedingss before chemotherapy was demonstrated to be non-inferior to individual dose IV ondansetron 32mg or IV dolasetron 100mg in the bar of acute CINV. Palonosetron 0.25mg ( but non 0.75mg ) was besides superior over the comparator groups in the bar of delayed CINV.
The bar of acute sickness and emesis associated with extremely emetogenic malignant neoplastic disease chemotherapy 8.
In a stage III randomized controlled test with 667 patients, individual dosage IV palonosetron 0.25mg and 0.75 milligram administered 30 proceedingss before chemotherapy with corticoids was non-inferior to IV ondansetron 32mg with corticoids for the bar of acute CINV. However, the survey did non happen high quality for palonosetron for delayed CINV. The non-inferiority of palonosetron demonstrated here requires the co-administration of a contraceptive corticoid.
The bar of acute sickness and emesis associated with reasonably emetogenic malignant neoplastic disease chemotherapy 8.
In a randomized control survey with 635 patients, individual dose unwritten palonosetron 0.25mg, 0.5mg, or 0.75mg 1 hr before chemotherapy was shown to be non-inferior to individual dose IV palonosetron 0.25mg 30 proceedingss before chemotherapy for the bar of acute CINV. Efficacy was further improved when either unwritten or IV palonosetron was used in concurrence with corticoids.
Systematic reappraisal and meta-analysis 3
A recent systematic reappraisal and meta-analysis of randomized controlled trails investigated the efficaciousness of a individual IV dosage of palonosetron 0.25mg compared to other 5-HT3 receptor adversaries ( ondansetron, granisetron, and dolasetron ) in patients having reasonably to extremely emetogenic chemotherapy. Palonosetron was found to be significantly more effectual in forestalling ague and delayed CINV than first coevals agents.
The safety and tolerability of palonosetron did non differ significantly from ondansetron or dolasetron. The most common inauspicious effects include concerns ( 3-9 % ) and irregularity ( 2-5 % ) 2,9. Palonoestron appears to be the safest of the 5-HT3 receptor adversaries to utilize if hazard of QT protraction is a concern, although there is still a little hazard so use should be with cautiousness 10.
Palonosetron is non on the Ontario Drug Benefit ( ODB ) formulary unlike the other 5-HT3 receptor adversaries which are limited use drugs covered under the ODB. A individual dosage of palonosetron for CINV costs about $ 70 whereas ondansetron costs about $ 16-32 10,11.
Palenosetron is available in endovenous ( 0.05 mg/mL solution ) and unwritten preparations ( 0.5mg capsule ) 8.
Role in Clinical Practice
The 2011 antiemetics guidelines from the American Society of Clinical Oncology ( ASCO ) recommended Palonosetron for the bar of CINV from reasonably emetogenic chemotherapy agents 2. In the moderate emetic hazard class, a two drug combination of palonosetron ( twenty-four hours 1: 0.25mg IV ; 0.5mg viva voce ) , and Decadron ( yearss 1-3: 8mg IV/PO ) was recommended. Palonosetron was besides a curative option in the twenty-four hours one regimen for the high emetic hazard class: NK1 receptor adversary ( twenty-four hours 1-3 for aprepitant ; twenty-four hours 1 merely for fosaprepitant ) , a 5-HT3 receptor adversary ( twenty-four hours 1 ) , and Decadron ( yearss 1-3 or 1-4 ) .