G-CHOP is a frontline chemotherapy regimen used for diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma, replacing rituximab with obinutuzumab (Gazyva) in the standard R-CHOP regimen.
G-CHOP Components:
| Drug | Role / Mechanism |
|---|---|
| G – Obinutuzumab | Anti-CD20 type II monoclonal antibody (glycoengineered for enhanced ADCC) |
| C – Cyclophosphamide | Alkylating agent |
| H – Doxorubicin (Hydroxydaunorubicin) | Anthracycline; topoisomerase II inhibitor |
| O – Vincristine (Oncovin) | Vinca alkaloid; inhibits microtubule formation |
| P – Prednisone | Corticosteroid; lympholytic and anti-inflammatory |
Typical Dosing (21-day cycles):
- Obinutuzumab: 1000 mg IV on Day 1 of each cycle (Cycle 1 may be split: 100 mg on Day 1 and 900 mg on Day 2)
- Cyclophosphamide: 750 mg/m² IV Day 1
- Doxorubicin: 50 mg/m² IV Day 1
- Vincristine: 1.4 mg/m² IV Day 1 (max 2 mg)
- Prednisone: 100 mg PO daily Days 1–5
Indications:
- Follicular lymphoma (G-CHOP or G-bendamustine used)
- Occasionally used in DLBCL as an alternative to R-CHOP (not standard)
Key Toxicities:
- Infusion-related reactions (higher risk than rituximab)
- Myelosuppression (especially neutropenia)
- Peripheral neuropathy (vincristine-related)
- Cardiotoxicity (doxorubicin)
- Infections, including hepatitis B reactivation
- Steroid-related effects (hyperglycemia, mood changes)
Pharmacist Monitoring/Considerations:
- Premedications required before obinutuzumab: acetaminophen, antihistamines, corticosteroids
- Monitor CBC, LFTs, renal function
- Prophylaxis for infections (e.g., PCP, antiviral, antifungal if needed)
- Growth factor support (G-CSF) may be required
- Hepatitis B screening before starting treatment