Response rates, duration of response, and dose response effects in phase I studies of antineoplastics

Invest New Drugs. 1991 Feb;9(1):115-22. doi: 10.1007/BF00194562.


Over a period of 14 years, 7,960 patients were treated in 228 phase I trials. In these patients, there were 75 complete and 432 partial responses for an overall objective response rate of 6%. Complete responses lasted a median of six months (range 1-18), while partial responses lasted a median of three months (range 1-17). Of note is that no drug has made it to the market which has not had a response in phase I trials. Responses were noted in very diverse histologic types of tumors. Although there were responses at doses which were as low as 3-5% of the recommended dose for phase II trials, the majority of responses did occur at 80-120% of the dose recommended for phase II trials. Although the response rate in phase I trials is indeed low, responses do occur. This response rate information should help the clinician provide facts for the patient considering a phase I trial with new anticancer agents. These findings also emphasize that although phase I trials are characteristically dose-finding studies, if no responses are noted in phase I studies, it is unlikely the drug will be used routinely in the clinic.

Publication types

  • Meta-Analysis
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antineoplastic Agents / therapeutic use*
  • Clinical Trials as Topic / methods
  • Data Interpretation, Statistical
  • Dose-Response Relationship, Drug
  • Drug Evaluation
  • Humans
  • Meta-Analysis as Topic
  • Neoplasms / drug therapy
  • Prognosis


  • Antineoplastic Agents