Ganciclovir is Used to Treat Cytomegalovirus (CMV)
The correct answer is D. Cytomegalovirus - ganciclovir is specifically indicated for CMV disease treatment and prophylaxis in immunocompromised patients, including transplant recipients and those with HIV/AIDS. 1
Primary Indication and Mechanism
- Ganciclovir is an acyclic nucleoside analogue that inhibits CMV replication by preferentially phosphorylating in CMV-infected cells and competitively inhibiting viral DNA polymerase 1
- The drug achieves 100-fold greater triphosphate concentrations in CMV-infected cells compared to uninfected cells, demonstrating its selective antiviral activity 1
- FDA-approved indications include prevention of CMV disease in solid organ transplant recipients, prevention in advanced HIV patients at risk, and maintenance treatment of CMV retinitis 1
Clinical Efficacy Evidence
Treatment of Active CMV Disease:
- In transplant recipients with severe CMV infection, ganciclovir demonstrates clinical improvement rates of 84% for CMV retinitis, 83% for gastrointestinal CMV, and 72% for CMV pneumonia 2
- Virologic response occurs in 92% of patients with sequential cultures showing clearance of CMV from blood, urine, or throat washings 2
- In liver and kidney transplant recipients with severe CMV infection, 90% of evaluable patients survived with resolution of fever (mean 5.3 days), improved liver function, and cleared pulmonary infiltrates 3
Prophylaxis Strategy:
- KDIGO guidelines recommend all kidney transplant recipients (except donor/recipient both CMV-negative) receive oral ganciclovir or valganciclovir prophylaxis for at least 3 months post-transplant and 6 weeks after T-cell-depleting antibody treatment 4
- Pre-emptive therapy initiated when BKV plasma levels exceed 10,000 copies/ml or with positive CMV monitoring reduces disease incidence to 1-3% 4
Dosing Protocols by Clinical Scenario
Serious/Tissue-Invasive CMV Disease:
- Intravenous ganciclovir 5 mg/kg every 12 hours for 2-3 weeks is recommended for CMV encephalitis, though therapeutic failures are common with monotherapy 4
- Combination therapy with ganciclovir (5 mg/kg IV q12h) plus foscarnet (60 mg/kg IV q8h or 90 mg/kg IV q12h) for 3 weeks achieves improvement/stabilization in 74% of HIV patients with CMV encephalitis or myelitis 4
Non-Serious CMV Disease in Adults:
- Either IV ganciclovir or oral valganciclovir can be used for mild CMV disease 4
- Oral valganciclovir 900 mg twice daily for 21 days is noninferior to IV ganciclovir for CMV disease treatment in solid organ transplant recipients, with comparable viremia eradication rates (45.1% vs 48.4% at Day 21) 5
Pediatric Considerations:
- All CMV disease in pediatric transplant recipients requires IV ganciclovir treatment 4
- For congenital CMV, valganciclovir for 6 months improves developmental outcomes and prevents hearing loss progression, superior to 6-week courses 6
Why Not the Other Options
Influenza A (Option A):
- Treated with neuraminidase inhibitors (oseltamivir, zanamivir), not ganciclovir 4
Herpes Simplex (Option B):
- Acyclovir is the drug of choice, with dosing of 10-20 mg/kg IV every 8 hours for 14-21 days for HSV encephalitis 4
- While ganciclovir has activity against HSV in vitro, it is not indicated for HSV treatment 1
Herpes Zoster (Option C):
- Treated with acyclovir, valacyclovir, or famciclovir 4
- Ganciclovir is not the standard treatment despite activity against herpes viruses 1
Critical Adverse Effects to Monitor
- Neutropenia occurs in 35-42% of patients, with higher rates (60%) in bone marrow transplant recipients 2, 7
- Thrombocytopenia develops in 19% of patients 2
- Dose modification may be required for neutropenia; granulocyte colony-stimulating factor can be used for severe cases 6
- Weekly monitoring of CMV by nucleic acid testing or pp65 antigenemia is recommended during treatment 4