Clinical benefit in Phase-I trials of novel molecularly targeted agents: does dose matter?

Br J Cancer. 2009 May 5;100(9):1373-8. doi: 10.1038/sj.bjc.6605030.


Phase-I trials traditionally involve dose-escalation to determine the maximal tolerated dose (MTD). With conventional chemotherapy, efficacy is generally deemed to be dose-dependent, but the same may not be applicable to molecularly targeted agents (MTAs). We analysed consecutive patients included in Phase-I trials at the Royal Marsden Hospital from 5 January 2005 to 6 June 2006. We considered only trials of monotherapy MTAs in which the MTD was defined. Three patient cohorts (A, B, and C) were identified according to the dose received as a percentage of the final trial MTD (0-33%, 34-65%, >66%). Potential efficacy was assessed using the non-progression rate (NPR), that is, complete/partial response or stable disease for at least 3 months by RECIST. A total of 135 patients having progressive disease before enrolment were analysed from 15 eligible trials. Median age was 57 years (20-86); male : female ratio was 1.8 : 1. Cohort A, B, and C included 28 (21%), 22 (16%), and 85 (63%) patients; NPR at 3 and 6 months was 21% and 11% (A), 50% and 27% (B), 31% and 14% (C), respectively, P=0.9. Median duration of non-progression (17 weeks; 95% CI=13-22) was not correlated with the MTD level, P=0.9. Our analysis suggests that the potential for clinical benefit is not confined to patients treated at doses close to the MTD in Phase-I trials of MTAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Agents / toxicity*
  • Clinical Trials, Phase I as Topic / standards*
  • Clinical Trials, Phase I as Topic / statistics & numerical data
  • Disease Progression
  • Drug Tolerance*
  • Drug-Related Side Effects and Adverse Reactions
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neoplasms / drug therapy*
  • Patient Selection
  • Young Adult


  • Antineoplastic Agents