87% of Patients With CIDP Transitioned From IVIG to Subcutaneous Efgartigimod in Phase 4 Study

New phase 4 data presented at the 2026 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Annual Meeting suggest that people with chronic inflammatory demyelinating polyneuropathy (CIDP) receiving stable intravenous immunoglobulin (IVIG) therapy may be able to transition directly to subcutaneous Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc [efgartigimod PH20]; argenx, Boston, MA), initiated within 1 week of their final IVIG dose.

The phase 4, open-label, multicenter study (NCT06637072) enrolled 23 adults with CIDP who had received stable IVIG doses of 0.5 to 2 g/kg every 3 to 6 weeks for at least 3 doses. Participants discontinued IVIG and began treatment with Vyvgart Hytrulo 1000 mg once weekly within 1 week, continuing treatment for 12 weeks.

The primary endpoint was the proportion of participants who continued Vyvgart Hytrulo treatment during the 12-week treatment period. Secondary measures included quality of life, patient perceptions of disease improvement and severity, treatment satisfaction, and safety and tolerability.

CIDP Disease Severity Remains Stable After IVIG-to-Efgartigimod Switch

Overall, 20 of 23 participants (87.0%) continued Vyvgart Hytrulo treatment through the 12-week treatment period, meeting the study's primary endpoint. Additional findings included the following:

• Disease severity remained stable during the transition from IVIG to Vyvgart Hytrulo.
• 56.5% of participants reported improvement on the Patient Global Impression of Change (PGI-C) at their final assessment.
• Quality of life and treatment satisfaction remained stable after the switch.
• Vyvgart Hytrulo treatment was generally well tolerated, with safety findings consistent with its established safety profile.

Clinical Implications for Neurologists

This study addresses a practical question not directly answered by the previous phase 2 clinical trial, ADHERE (NCT04281472), which also evaluated treatment with Vyvgart Hytrulo for adults with CIDP. In ADHERE, participants were required to demonstrate clinical deterioration before receiving treatment with Vyvgart Hytrulo. In routine practice, however, disease worsening is not required before treatment initiation, leaving uncertainty about how patients who are stable on IVIG can transition to Vyvgart Hytrulo.

The new findings, presented at AANEM 2026, provide preliminary evidence for a direct IVIG-to-Vyvgart Hytrulo transition strategy in CIDP, potentially allowing patients to change maintenance therapy without waiting for clinical deterioration or a treatment-free washout period between treatments.

The findings should be interpreted in the context of the study's small sample size, open-label design, lack of a comparator group, and 12-week treatment period. Larger and longer-term studies are needed to determine whether disease stability is maintained and which patients may be best suited to this transition strategy.

Sources

1. Seth A, Lerman A, Remmerie A, et al. Intravenous immunoglobulin to subcutaneous efgartigimod PH20 transition in chronic inflammatory demyelinating polyradiculoneuropathy: a phase 4 study in progress. Poster presented at: American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Annual Meeting; September 29-October 2, 2026; Orlando, FL.
2. Seth A, Lerman A, Remmerie A, et al. Intravenous immunoglobulin to subcutaneous efgartigimod PH20 transition in chronic inflammatory demyelinating polyradiculoneuropathy: a phase 4 study in progress. AANEM 2026 Annual Meeting Abstracts Guide. Abstract 128. American Association of Neuromuscular & Electrodiagnostic Medicine; 2026.