Purpose: To propose a classification of the acute emetogenicity of antineoplastic chemotherapy agents, and to develop an algorithm to define the emetogenicity of combination chemotherapy regimens.
Methods: A Medline search was conducted to identify (1) clinical trials that used chemotherapy as single-agent therapy, and (2) major reviews of antiemetic therapy. The search was limited to patients who received commonly used doses of chemotherapy agents, primarily by short (< 3 hours) intravenous infusions. Based on review of this information and our collective clinical experience, we assigned chemotherapy agents to one of five emetogenic levels by consensus. A preliminary algorithm to determine the emetogenicity of combination chemotherapy regimens was then designed by consensus. A final algorithm was developed after we analyzed a data base composed of patients treated on the placebo arms of four randomized antiemetic trials.
Results: Chemotherapy agents were divided into five levels: level 1 (< 10% of patients experience acute [< or = 24 hours after chemotherapy] emesis without antiemetic prophylaxis); level 2 (10% to 30%); level 3 (30% to 60%); level 4 (60% to 90%); and level 5 (> 90%). For combinations, the emetogenic level was determined by identifying the most emetogenic agent in the combination and then assessing the relative contribution of the other agents. The following rules apply: (1) level 1 agents do not contribute to the emetogenic level of a combination; (2) adding > or = one level 2 agent increases the emetogenicity of the combination by one level greater than the most emetogenic agent in the combination; and (3) adding level 3 or 4 agents increases the emetogenicity of the combination by one level per agent.
Conclusion: The proposed classification schema provides a practical means to determine the emetogenic potential of individual chemotherapy agents and combination regimens during the 24 hours after administration. This system can serve as a framework for the development of antiemetic guidelines.