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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: Mol Oncol. 2014 Aug 14;9(5):997–1007. doi: 10.1016/j.molonc.2014.07.025

Table 1.

Similarities and differences in phase I trials for different drug classes

Trial Elements Cytotoxics MTAs and Immunotherapies
Primary end point RP2D RP2D
Secondary end points Toxicity (MTD, DLT), response rate PK or PD (molecular) parameter, toxicity, response rate
Dose escalation decisions Toxicity based Escalate based on toxicity or to a desired on-target effect
PK parameters Cmax may correlate with toxicity t1/2 may predict recovery from toxicity PK parameter (e.g. Cmax, Cmin, AUC) that correlates with desired target stimulation or suppression
Reasons for selecting RP2D Toxicity.
RP2D must have tolerable toxicities and may demonstrate anti-tumor activity.		 Combination of toxicity and PD/PK parameters.
RP2D may demonstrate desired target effects with anti-tumor activity and tolerable toxicity.

MTA, molecular targeted agent; RP2D, recommended phase II dose; MTD, maximum tolerated dose; DLT, dose limiting toxicity; PK, pharmacokinetic; PD, pharmacodynamic; AUC area under the curve; SD, stable disease.