You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A randomized phase II trial of 5-fluorouracil , with or without human interferon-beta , for advanced colorectal cancer . This study compared the efficacy and safety of 5-fluorouracil ( 5-FU ) monotherapy to that of 5-FU combined with natural human interferon-beta ( IFN-beta ) in patients with unresectable , advanced colorectal carcinoma . Forty-nine chemotherapy-naive patients were randomized to 5-FU alone or to the combination . All patients received 750 mg m ( -2 ) day ( -1 ) 5-FU for 5 days by continuous intravenous ( i.v . ) infusion , followed after day 15 by a weekly i.v . bolus of 750 mg m ( -2 ) . IFN-beta was injected intramuscularly three times weekly at 9 M IU . Treatment continued for 52 weeks , or until disease progression or intolerable toxicity . Clinical endpoints were tumor response , time to progression , survival and toxicity . The addition of IFN-3 to 5-FU significantly improved response rate ( 33.3 % vs 4.5 % for evaluable patients ; P = 0.021 ) , time to progression ( median 7.2 vs 4.2 months ; P = 0.0435 ) , and survival time ( median 15.9 vs 7.2 months ; P = 0.038 ) without significantly increasing toxicity compared to 5-FU alone . Cumulative 5-FU dose was higher with combined therapy ( P < 0.001 ) : more patients receiving monotherapy discontinued treatment because of disease progression . Fever was more frequent with combined therapy ( P = 0.008 ) ; there were no other differences in toxicity . The only grade IV toxicity observed was neutropenia ( two patients per group ) . A randomized phase III trial has been initiated to confirm the synergy between 5-FU and IFN-beta .
{"Intervention": ["5-fluorouracil", "human interferon-beta", "5-fluorouracil ( 5-FU ) monotherapy", "IFN-beta", "IFN-3 to 5-FU", "5-FU", "5-FU combined with natural human interferon-beta ( IFN-beta )"], "Outcome": ["time to progression", "efficacy and safety", "improved response rate", "tumor response", "disease progression", "Cumulative 5-FU dose", "Fever", "grade IV toxicity", "survival time", "survival and toxicity", "toxicity", "intolerable toxicity"], "Participant": ["advanced colorectal cancer", "advanced colorectal carcinoma", "Forty-nine", "chemotherapy-naive"]}