What Skin Side Effects Does Amivantamab (Rybrevant) Cause, and How Are They Treated?

Amivantamab (Rybrevant), a bispecific antibody targeting EGFR and MET, offers an important treatment option, particularly for patients with metastatic non-small cell lung cancer (NSCLC) carrying an EGFR exon 20 insertion mutation (Exon20ins). This treatment has expected skin toxicities. This article brings together recommendations for preventing and treating skin toxicities during amivantamab treatment.

Main Skin Toxicities

Acneiform rash and paronychia are the most common skin side effects in patients receiving amivantamab. Other effects included hypertrichosis in 50% of men and hirsutism in 80% of women. This article analyzes skin side effects in 7 patients.

FIGURE 1: Development of skin toxicities in seven patients receiving amivantamab, from treatment initiation through 31 December 2021.

Each row in the image represents the severity of skin toxicity in a different patient and how these side effects change over time. Each color indicates a different toxicity: red for paronychia, green for acneiform rash, turquoise for skin fissures, and purple for hirsutism/hypertrichosis.

The axes are defined as follows:

• The Y-axis shows side effect grades from 0 to 3.
• The X-axis shows the number of treatment days (time).

For example, in the first patient (p1, male, aged 54, starting dose 1400mg), the highest-grade paronychia occurred after 308 days and was recorded as grade 3. Acneiform rash reached grade 3 after 343 days in this patient. Other patients and their side effects are coded similarly.

FIGURE 2: The photographs below show the severity grades of the two main skin side effects seen in patients receiving amivantamab: 

1. Grade 1 Paronychia: Mild redness and swelling around the nail, with no open wound or sign of infection.
2. Grade 2 Paronychia: More pronounced redness and swelling around the nail, with signs of oozing or crusted wounds.
3. Grade 3 Paronychia: Severe redness, swelling, and pus-filled open wounds around the nail, potentially indicating a serious infection risk.
4. Grade 1 Acneiform Rash: Mild skin rash and redness.
5. Grade 2 Acneiform Rash: More intense redness and rash, indicating a serious condition requiring treatment.
6. Grade 3 Acneiform Rash: Lesions on the scalp are shown. This serious condition involves intense, widespread rash and skin lesions.

Treating Amivantamab-Related Skin Side Effects

Managing the skin side effects of amivantamab focuses on classifying, preventing, and treating toxicities. A multidisciplinary approach should be adopted for dermatological toxicities, with psychological support considered an important component.

Treatments for skin toxicities include topical corticosteroids, tetracycline antibiotics, and skin moisturizers. Preventive measures are also recommended at least 14 days before starting treatment to prevent acneiform rash and paronychia.

TABLE: Guidelines for managing acneiform rash, paronychia, and skin cracks/fissures during amivantamab treatment.