Class: Immune checkpoint inhibitor – PD-L1 monoclonal antibody (IgG1) with antibody-dependent cell-mediated cytotoxicity (ADCC) potential (unlike some other PD-L1 inhibitors).
Mechanism:
- Binds PD-L1, blocking interaction with PD-1 and CD80
- Restores T-cell activation and antitumor immunity
- Unique feature: retains Fc region activity, enabling recruitment of NK cells for ADCC against tumor cells
Key Oncology Indications
- Metastatic Merkel cell carcinoma (MCC) – first-line or after prior therapy
- Locally advanced or metastatic urothelial carcinoma (platinum-treated)
- Maintenance therapy for advanced urothelial carcinoma not progressing after platinum-based chemo (JAVELIN Bladder 100 trial)
- Investigated in combinations for other solid tumors
Typical Adult Dosing
- 800 mg IV every 2 weeks
- Infuse over 60 minutes; no routine premedication unless prior infusion reaction
- Continue until disease progression or unacceptable toxicity
Toxicity Profile & Pharmacist Monitoring
| Toxicity Type | Examples | Monitoring / Prevention |
|---|---|---|
| Immune-mediated | Pneumonitis, hepatitis, colitis, endocrinopathies (thyroiditis, adrenal insufficiency, hypophysitis), nephritis, myocarditis | Baseline & periodic LFTs, TFTs, cortisol, renal function, patient education |
| Infusion-related reactions (IRRs) | Fever, chills, rigors, hypotension, rash | Premed with antihistamine + acetaminophen for first 4 infusions in MCC; monitor closely during infusion |
| Dermatologic | Rash, pruritus, vitiligo | Symptomatic management, topical steroids if mild |
| Other | Fatigue, nausea, arthralgia | Supportive care as needed |
Pharmacist Pearls
- Higher infusion reaction risk compared to some other PD-L1 inhibitors — especially in MCC → premedicate early cycles
- Grade ≥2 immune toxicities → withhold avelumab and initiate corticosteroids (prednisone 1–2 mg/kg/day), taper over ≥4 weeks before resuming
- Monitor for late-onset immune toxicities even after discontinuation
- Avoid high-dose systemic steroids before initiation unless required for comorbidities
- Counsel patients on early reporting of new respiratory, GI, endocrine, or skin symptoms