Phase 3 study of Efgartigimod PH20 SC in patients with gMG
Research type
Research Study
Full title
A Phase 3, Randomized, Open-Label, Parallel-Group Study to Compare the Pharmacodynamics, Pharmacokinetics, Efficacy, Safety, Tolerability, and Immunogenicity of Multiple Subcutaneous Injections of Efgartigimod PH20 SC with Multiple Intravenous Infusions of Efgartigimod in Patients with Generalized Myasthenia Gravis (ADAPT)
IRAS ID
1003608
Contact name
Wim Parys
Sponsor organisation
argenx BV
Eudract number
2020-004085-19
Clinicaltrials.gov Identifier
Research summary
Research Summary
Generalised Myasthenia Gravis (gMG) is a rare, long-term auto-immune condition that causes muscle weakness. It is caused by problems with signals sent between the nerves and the muscles, due to the body’s immune system mistakenly attacking and damaging the communication system between the nerves and the muscles. This causes the muscles to become weak and easily tired.
There is no current standard of care for gMG. The medications typically used include nonsteroidal immunosuppressants, steroids, and acetylcholinesterase inhibitors, monoclonal antibodies, and Ig therapy (called IVIg).
This is a Phase III study of Efgartigimod PH20 SC in patients with gMG sponsored by argenx BV. The aim of the study is to compare the effects of two different formulations of efgartigimod in gMG patients. Firstly, efgartigimod combined with PH20 (a protein that helps the uptake and spreading of injected drugs). This formulation (efgartigimod PH20 SC) will be injected under the skin of the lower stomach. Secondly, efgartigimod given through an infusion (efgartigimod IV). Efgartigimod acts to reduce antibody levels by binding to FcRn (a protein which keeps the antibody levels up). This means the antibodies attacking the communication systems and damaging the nerves and muscles will also be reduced, therefore, efgartigimod may help improve gMG symptoms.
About 46 to 76 people with gMG will take part in this study and it will last up to 12 weeks, with each participant having 11 study visits. It involves a screening period to check eligibility for participation in the study, which is followed by the treatment period. At the first treatment period visit participants will be randomly assigned to an efgartigimod formulation. Participants will receive a total of 4 doses of the drug at weekly study visits. These visits also involve several tests / questionnaires. Participants will then enter a treatment-free follow-up period of 7 weeks.Summary of Results
Main reason for the study: 'Myasthenia gravis (MG) is an autoimmune disease in which a protein called IgG antibody blocks or slows down communication between nerves and muscles. This leads to muscle weakness and difficulty in movement. This study included participants with a type of MG called generalized myasthenia gravis (gMG).The study medicine, efgartigimod, was designed to decrease the symptoms of MG. The study compared how well two ways of giving efgartigimod decreases IgG levels, including disease-causing IgG antibodies, in participants at Day 29. The participants were given efgartigimod either through a needle into their vein (intravenous [IV] infusion) or through a needle under their skin (subcutaneous [SC] injection). Efgartigimod is available in some countries as an IV treatment for people with gMG.
Medicines studied: Participants in this study were given efgartigimod, a study medicine designed to decrease IgG antibodies.
About the participants: The study included 110 participants.
Results of this study: The study compared the decrease in IgG levels at Day 29 in participants who were given efgartigimod SC and in those who were given efgartigimod IV. For this comparison, study staff collected blood samples from the participants. Each participant’s IgG antibody level was measured before they received efgartigimod at Day 1 and at several times after they received efgartigimod. The difference in IgG levels at Day 1 and at Day 29 was compared. The average decrease in IgG antibody levels from Day 1 to Day 29 was calculated as a percent for both the groups. The decrease in IgG levels after 29 days of treatment was similar in both treatment groups: 66% for efgartigimod SC and 62% for efgartigimod IV.
The study also compared the Myasthenia Gravis Activities of Daily Living (MG-ADL) between the 2 treatment groups. Participants answered 8 questions about their daily life (talking, breathing, chewing, swallowing, …). Based on the answers, an MG-ADL score was given. A participant was an MG-ADL responder if their MG-ADL score improved by at least 2 points for 4 weeks in a row compared to their first MG-ADL score. The percentage of MG-ADL responders was the same in both treatment groups (69%).
Safety: No serious side effects happened during the study. Non-serious side effects happened in more participants due to efgartigimod given SC compared to efgartigimod given IV.
REC name
North West - Haydock Research Ethics Committee
REC reference
21/NW/0064
Date of REC Opinion
30 Apr 2021
REC opinion
Further Information Favourable Opinion