Resistance scenarios after halting therapy in the metastatic disease setting
| Administration schedule | Timing of tumor regrowth | Resistance phenotype |
| Continuous | ≤12 weeks after the last dose | Primary resistance to the combination |
| >12 weeks after the last dose | Secondary resistance to the combination | |
| Induction | ≤12 weeks after the last dose | Primary resistance to the drug that was continued |
| >12 weeks after the last dose | Must be assessed based on rechallenge |
These definitions assume that adequate drug exposure (ie, 12 weeks or 2–4 cycles) was provided.