Amlitelimab is a novel, investigational drug being developed by Sanofi for the treatment of various immune-mediated inflammatory diseases, most notably moderate-to-severe atopic dermatitis (AD), also known as atopic eczema. It is a fully human, non-depleting monoclonal antibody that targets the OX40 ligand (OX40L), a key player in T-cell-driven inflammation. 

 

Amlitelimab works by blocking the interaction between OX40L, found on antigen-presenting cells (APCs), and OX40, a receptor expressed on activated T cells. This interaction is believed to play a critical role in the chronic inflammation associated with conditions like atopic dermatitis by promoting T-cell survival, proliferation, and cytokine release. By disrupting this pathway, amlitelimab aims to restore the balance between pro-inflammatory and regulatory T cells, potentially offering a more targeted and durable approach to managing these conditions compared to existing therapies. 

 

Amlitelimab has shown promising results in clinical trials for moderate-to-severe atopic dermatitis. A Phase 2b study demonstrated significant improvement in signs, symptoms, and itch. Clinically meaningful improvements were seen in EASI and IGA scores at 16 and 24 weeks. A significant number of responders maintained improvements for 28 weeks off-treatment, suggesting potential durability and less frequent dosing. A Phase 3 program is ongoing. 

 

Amlitelimab is also being studied for other inflammatory conditions, including asthma, hidradenitis suppurativa, and interstitial lung disease secondary to systemic sclerosis. 

 

Amlitelimab has been generally well-tolerated in trials. Common side effects include nasopharyngitis, COVID-19, and headache. Some studies showed more AD worsening in the placebo group than in those treated with amlitelimab. 

 

Amlitelimab is an investigational drug and is not yet approved by regulatory agencies. Phase 3 trials are ongoing, as are long-term safety and effectiveness studies.