Amivantamab Dosing Schedule in Recurrent Head and Neck Carcinoma
Administer subcutaneous amivantamab at 1600 mg (2240 mg if ≥80 kg) on Cycle 1 Day 1, then 2400 mg (3360 mg if ≥80 kg) every 3 weeks thereafter until disease progression or unacceptable toxicity 1, 2.
Dosing Protocol
Weight-Based Dosing
Patients <80 kg:
- First dose (Cycle 1, Day 1): 1600 mg subcutaneous
- Subsequent doses: 2400 mg every 3 weeks
Patients ≥80 kg:
- First dose (Cycle 1, Day 1): 2240 mg subcutaneous
- Subsequent doses: 3360 mg every 3 weeks
This weight-based adjustment is critical because amivantamab clearance increases with body weight, and patients ≥80 kg have 30-40% lower drug exposure at the same dose 3.
Administration Details
Subcutaneous formulation is strongly preferred over intravenous delivery for head and neck cancer patients. The subcutaneous route reduces administration time to ≤10 minutes (versus 2.3 hours for IV beyond cycle 3) and dramatically lowers infusion-related reaction rates to 7% compared to historical IV data 2, 4. This eliminates the need for split-dose administration over 2 days that was required with IV formulation 4.
Treatment Duration
Continue amivantamab until:
- Disease progression by RECIST 1.1 criteria, OR
- Unacceptable toxicity requiring permanent discontinuation
The pivotal OrigAMI-4 study demonstrated median progression-free survival of 6.8 months, with 56% of responses lasting ≥6 months 1.
Patient Selection Criteria
Amivantamab is indicated for patients with:
- Non-HPV-related recurrent/metastatic head and neck squamous cell carcinoma
- Prior exposure to: PD-(L)1 checkpoint inhibitor AND platinum-based chemotherapy
- Exclusions: Prior anti-EGFR therapy (e.g., cetuximab) and p16-positive oropharyngeal cancer were exclusionary in the pivotal trial 1
Important caveat: Real-world data suggests amivantamab may retain activity even after cetuximab failure (30% ORR in cetuximab-exposed patients), though this was not the studied population in the pivotal trial 5.
Dose Modifications
For Infusion-Related Reactions (IRRs)
- Grade 1-2: Slow or interrupt infusion; resume at 50% rate when symptoms resolve
- Grade 3: Permanently discontinue 3
For Dermatologic Toxicity
- Grade 1-2: Initiate supportive care; reassess after 2 weeks
- Grade 3: Withhold until recovery to ≤Grade 2, then resume at reduced dose
- Grade 4 or severe bullous conditions: Permanently discontinue 3
For Venous Thromboembolism
- Grade 2-3: Withhold amivantamab, initiate anticoagulation, resume at same dose once anticoagulated
- Grade 4 or recurrent Grade 2-3 despite anticoagulation: Permanently discontinue 3
For Other Grade 3-4 Toxicities
- Grade 3: Withhold until recovery to ≤Grade 1; resume at same dose if recovery within 1 week, reduced dose if recovery within 1-4 weeks
- Grade 4: Withhold until recovery; resume at reduced dose if recovery within 4 weeks
- Permanently discontinue if no recovery within 4 weeks 3
Expected Efficacy
Based on the pivotal OrigAMI-4 cohort 1 data in 102 patients:
- Objective response rate: 42% (95% CI, 32-52%)
- Complete response rate: 15%
- Median duration of response: Not reached
- Median overall survival: 12.5 months 1
This represents substantially superior activity compared to historical controls with single-agent paclitaxel or cetuximab (ORR 21-24%) in this treatment setting 1.
Safety Profile
Most common treatment-related adverse events:
- Hypoalbuminemia (90%)
- Acneiform rash (70-86%)
- Infusion-related reactions (7-45%, mostly Grade 1-2)
- Fatigue (71%)
Treatment discontinuation rate due to toxicity is low at 8%, and the safety profile is manageable with supportive care 1, 2, 5.
Practical Considerations
Premedication is essential to minimize IRRs, though specific protocols were not detailed in the FDA label. The subcutaneous formulation's dramatically lower IRR rate (7% vs historical IV rates) makes it the clear choice when available 2, 4.
No dose adjustments are needed for mild-moderate renal impairment, mild hepatic impairment, age, sex, or race 3.