Table 1

Definitions of primary and secondary resistance in advanced disease setting

Resistance phenotypeDrug exposure requirementBest responseConfirmatory scan for PD requirementConfirmatory scan timeframe
Primary resistance≥6 weeksPD; SD for <6 months*Yes†At least 4 weeks after initial disease progression‡
Secondary resistance≥6 monthsCR, PR, SD for >6 months*Yes†At least 4 weeks after disease progression‡
  • *Indolent tumor types might require modification of the timeframe.

  • †Other than when tumor growth is very rapid and patients are deteriorating clinically.

  • ‡Per Response Evaluation Criteria in Solid Tumors 1.1.

  • CR, complete response; PD, programmed death; PR, partial response; SD, stable disease.