Table 3

Minimum exposure and best response definition for primary resistance to immune checkpoint inhibitor−chemotherapy combinations in advanced tumor settings

Resistance phenotypeExposure requirementTiming of RECIST progression*Confirmatory scan
Primary resistance†6–8 weeks‡≤6 monthsNot required
Secondary or late resistance†>6 months>6 monthsNot required
  • *Regardless of best response.

  • †For patients that experience recurrent disease after stopping therapy for reasons other than toxicity, no uniform clinical definitions of resistance applicable across disease states could be described.

  • ‡For rapidly progressing disease, any exposure is adequate.

  • RECIST, Response Evaluation Criteria In Solid Tumors.