Table 2. Comparison of irRC, irRECIST and iRECIST response assessment.
| Response assessment | irRC | irRECIST | iRECIST |
|---|---|---|---|
| CR | Complete disappearance of all lesions (whether measurable or not, and no new lesions) | Disappearance of all target and non-target lesions | Disappearance of all target and non-target lesions |
| Confirmation by a repeat, consecutive CSI controls no less than 4 weeks from the date first documented | Nodal short axis diameter <10 mm | Nodal short axis diameter <10 mm | |
| No new lesions | No new lesions | ||
| Confirmation of response is not mandatory | |||
| PR | Decrease in TTB ≥50% relative to baseline | Decrease of ≥30% in tumour burden relative to baseline | Decrease of ≥30% in tumour burden relative to baseline |
| Confirmed by a consecutive CSI control at least 4 weeks after first documentation | Non-unequivocal progression of non-target lesions | Non-unequivocal progression of non-target lesions | |
| No new lesions | No new lesions | ||
| PD | Increase in tumor burden ≥25% relative to nadir | ≥20% increase and ≥5 mm absolute increase in TMTB compared to nadir (minimum recorded tumor burden) | iUPD: ❖ Increase ≥20% of the sum of longest diameters compared with nadir (minimum 5 mm) or progression of non-target lesions or new lesion; ❖ Confirmation is required minim 4–8 weeks later the first iUPD assessment |
| Confirmation by a repeat, consecutive CSI control no less than 4 weeks from the date first documented | irPD for non-target or new non-measurable lesions | iCPD: ❖ Increased size of target or non-target lesions; ❖ Increase in the sum of new target lesions >5 mm; ❖ Progression of the non-target lesions; ❖ Appearance of another new lesion |
|
| Confirmation of progression is recommended minimum 4 weeks after the first irPD evaluation | |||
| SD | When neither PR nor PD can be established | When neither PR nor PD can be established | When neither PR nor PD can be established |
irRC, immune-related response criteria; irRECIST, immune-related Response Evaluation Criteria in Solid Tumors; iRECIST, immune RECIST; CR, complete response; PR, partial response; PD, progressive disease; SD, stable disease; CSI, cross-sectional imaging; TTB, total tumor burden; TMTB, total measured tumor burden; iUPD, unconfirmed progressive disease; iCPD, confirmed progressive disease.