12. Imatinib
(Glivec)Dose adjustments:
Dose modifications based on treatment-associated toxicity and trough levels of imatinib:
Toxicity
No toxicity Grade 1 Grade 2* Grade 3 Grade 4
TL < 550 ng/mL: increase two dose levels TL 550 - 1100 ng/mL: increase one dose level
TL < 550 ng/mL: increase two dose levels TL 550 - 1100 ng/mL: increase one dose level
TL < 550 ng/mL: increase one dose level TL 550 - 1100 ng/mL: increase one dose level
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
TL ≥ 1100 ng/mL: continue at the same dose level
TL ≥ 1100 ng/mL: continue at the same dose level
TL ≥ 1100 ng/mL: continue at the same dose level
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
TL = trough level imatinib
* If grade 2 toxicities are persistent or unbearable, consider treating them as grade 3.
** Patients who develop grade 4 hyperuricemia or grade 3 hypophosphatemia without clinical symptoms may continue treatment without interruption at the discretion of the investigator. Nausea, vomiting or diarrhea must persist at grade 3 or 4 despite maximal medical therapy. Patients who develop grade 3 or 4 lymphopenia without other dose-limiting events (e.g. opportunistic infection) may continue treatment without interruption. For specific dose modification guidelines regarding decreased ANC/platelet count see below.
Patients with hematologic malignancies (target: 1000 ng/mL):
Toxicity
No toxicity Grade 1 Grade 2* Grade 3 Grade 4
TL < 550 ng/mL: increase two dose levels TL 550 - 1000 ng/mL: increase one dose level
TL < 550 ng/mL: increase two dose levels TL 550 - 1000 ng/mL: increase one dose level
TL < 550 ng/mL: increase one dose level TL 550 - 1000 ng/mL: increase one dose level
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
TL ≥ 1000 ng/mL: continue at the same dose level
TL ≥ 1000 ng/mL: continue at the same dose level
TL ≥ 1000 ng/mL: continue at the same dose level
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level or to the previous dose level in case of previous dose escalation and resume
treatment**
TL = trough level imatinib
* If grade 2 toxicities are persistent or unbearable, consider treating them as grade 3.
** Patients who develop grade 4 hyperuricemia or grade 3 hypophosphatemia without clinical symptoms may continue study treatment without interruption at the discretion of the investigator. Nausea, vomiting or diarrhea must persist at grade 3 or 4 despite maximal medical therapy. Patients who develop grade 3 or 4 lymphopenia without other dose-limiting events (e.g. opportunistic infection) may continue study treatment without interruption. For specific dose modification guidelines regarding decreased ANC/platelet count see below.
Dose modifications based on treatment-associated toxicity in weeks without potential dose modifications based on trough levels of imatinib:
Toxicity
No toxicity Grade 1 Grade 2* Grade 3 Grade 4
Continue at the same dose level
Continue at the same dose level
Continue at the same dose level
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level and resume treatment**
Withhold dose until toxicity is ≤ grade 1 (or ≤ grade 2 in case of hematologic toxicity). For treatment related toxicity: reduce dose by one dose level and resume treatment**
* If grade 2 toxicities are persistent or unbearable, consider treating them as grade 3.
** Patients who develop grade 4 hyperuricemia or grade 3 hypophosphatemia without clinical symptoms may continue treatment without interruption at the discretion of the investigator. Nausea, vomiting or diarrhea must persist at grade 3 or 4 despite maximal medical therapy. Patients who develop grade 3 or 4 lymphopenia without other dose-limiting events (e.g. opportunistic infection) may continue treatment without interruption. For specific dose modification guidelines regarding decreased ANC/platelet count see below.
Specific dose modification guidelines
Absolute neutrophil count (ANC) and platelet count Chronic phase CML / GIST (standard dosing 400 mg OD) ANC/platelet count Dosing advice
ANC < 1.0 x 109/L or platelet count < 50 x 109/L
1. Stop dosing until ANC > 1.5 x 109/L or platelet count
> 75 x 109/L
2. Resume treatment at the same dose level
3. If ANC < 1.0 x 109/L or platelet count < 50 x 109/L again reduce dose by 300 mg
Accelerated phase CML / blastic crisis CML / Ph+ ALL (standard dosing 600 mg OD) ANC/platelet count Dosing advice
*ANC < 0.5 x 109/L or platelet count < 10 x 109/L
1. Examine if the cytopenia is related to the leukaemia (by performing a bone marrow aspiration or biopsy) 2. If not: reduce dose to 400 mg OD
3. If cytopenia lasts for 2 weeks: reduce dose to 300 mg OD
4. If cytopenia lasts for 4 weeks and is still unrelated to the leukaemia: stop dosing until ANC ≥ 1.0 x 109/L or platelet count ≥ 20 x 109/L
5. Resume treatment at 300 mg OD
* at least one month after start of treatment.
PK samples
- 4, 8 and 12 weeks after treatment initiation - 4 weeks after every dose adjustment
- every 12 weeks until treatment discontinuation