Despite the considerable progress achieved in the last 30 years, vomiting and, especially, nausea, continue to be two of the most distressing side-effects of cancer chemotherapy. In the late 1990s, several professional organisations published recommendations on the optimal antiemetic prophylaxis in patients submitted to chemotherapy and/or radiotherapy. The European Society of Medical Oncology (ESMO) and the Multinational Association of Supportive Care in Cancer (MASCC) published the results of the third Consensus Conference on antiemetics held in Perugia in June 2009 in Annals of Oncology in 2010 [1]. An update of these recommendations, including studies published from 1 January 2009 to 30 June 2015, was discussed in Copenhagen in June 2015 and is presented in this paper. The methodology for the guideline process is described in detail in the 2010 publication [1]. To change a 2010 recommendation or for a new guideline recommendation to be accepted, a consensus of at least 67% of the expert panellists was needed. As a general rule, the panel considered changes of 10% or greater to be sufficient to warrant the changing of a recommendation.

Introduction: The addition of neurokinin-1 receptor antagonists (NK₁RAs) to standard prophylaxis of 5-hydroxytryptamine-3 RA (5-HT₃RA) plus dexamethasone more effectively prevents chemotherapy-induced nausea and vomiting (CINV) associated with highly and moderately emetogenic chemotherapy. Areas covered: This review presents the evidence base for the use of oral and intravenous (IV) NK₁RAs, focusing on the pharmacologic and clinical properties as a class, and highlighting differences between agents. A PubMed literature search was conducted from 2000 to 2018. Expert opinion: Adherence to international antiemetic guidelines remains a clinical challenge. Strategies to simplify antiemetic regimens and facilitate their administration may improve compliance and treatment outcomes. The use of fixed-combination antiemetics offers clinical utility, in combining an NK₁RA with a 5-HT₃RA in a single oral dose. The use of long-lasting NK₁RAs and administering CINV prophylaxis closer to the time of chemotherapy may also assist with guideline and treatment compliance, diminishing the need for home-based administration, and potentially reducing resource utilization. The availability of IV and oral formulations of NK₁RAs and NK₁RA–5-HT₃RA fixed combinations offers further utility, particularly for those patients unsuited for oral administration. However, safety considerations with respect to injection site toxicity and hypersensitivity reactions of the new NK₁RA IV formulations deserve close attention.