Study: NCT04580121

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: RO7283420
Description: RO7283420 at RP2D will be administered by IV infusion or SC injection as per dosing schedule determined in Part B.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Tocilizumab
Description: Tocilizumab will be administered as an IV infusion 8 mg/kg (for participants with a weight of 30 kg and above) and 12 mg/kg (for participants with a weight of less than 30 kg). Tocilizumab will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Tocilizumab
Description: Tocilizumab will be administered as an IV infusion 8 mg/kg (for participants with a weight of 30 kg and above) and 12 mg/kg (for participants with a weight of less than 30 kg). Tocilizumab will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Tocilizumab
Description: Tocilizumab will be administered as an IV infusion 8 mg/kg (for participants with a weight of 30 kg and above) and 12 mg/kg (for participants with a weight of less than 30 kg). Tocilizumab will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dasatinib
Description: Dasatinib 100 mg film-coated tablets will be administered daily until symptom resolution (up to 100 mg twice daily \[BID\] for a maximum 3 days); orally. Dasatinib will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dasatinib
Description: Dasatinib 100 mg film-coated tablets will be administered daily until symptom resolution (up to 100 mg twice daily \[BID\] for a maximum 3 days); orally. Dasatinib will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dasatinib
Description: Dasatinib 100 mg film-coated tablets will be administered daily until symptom resolution (up to 100 mg twice daily \[BID\] for a maximum 3 days); orally. Dasatinib will be given as rescue medication.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dexamethasone
Description: 20 mg IV of dexamethasone will be administered as pre-medication at least 60 minutes prior to the all RO7283420 infusions or injections during cycle 1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dexamethasone
Description: 20 mg IV of dexamethasone will be administered as pre-medication at least 60 minutes prior to the all RO7283420 infusions or injections during cycle 1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Dexamethasone
Description: 20 mg IV of dexamethasone will be administered as pre-medication at least 60 minutes prior to the all RO7283420 infusions or injections during cycle 1.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Paracetamol/acetaminophen
Description: 500 or 1000 mg of paracetamol/acetaminophen will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Paracetamol/acetaminophen
Description: 500 or 1000 mg of paracetamol/acetaminophen will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Paracetamol/acetaminophen
Description: 500 or 1000 mg of paracetamol/acetaminophen will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Diphenhydramine
Description: 25 mg or 50 mg of diphenhydramine will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Diphenhydramine
Description: 25 mg or 50 mg of diphenhydramine will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Diphenhydramine
Description: 25 mg or 50 mg of diphenhydramine will be administered orally or by IV as pre-medication at least 30 minutes prior to each RO7283420 infusion or injection.