Detailed explanation of possible side effects of anifrolumab

Anilumab (anifrolumab) is a monoclonal antibody targeting the type I interferon receptor. It inhibits the abnormally active type I interferon signaling pathway by blocking the IFNAR1 receptor, thereby reducing autoimmune damage in patients with systemic lupus erythematosus (SLE). In 2021, it was approved by the US FDA for the treatment of patients with moderately to severely active SLE (especially those with high interferon gene expression characteristics), becoming another precision immunotherapy after belimumab. Despite its effectiveness, patients need to be wary of potential side effects ranging from mild infections to life-threatening allergic reactions.

Common anilumab side effects:

About 25%-30% of patients taking anilumab may develop upper respiratory tract infection, manifesting as cold-like symptoms such as nasal congestion, sore throat, cough, and some require short-term antibiotic treatment. Because drugs suppress the ability of the immune system to clear pathogens, the risk of herpes zoster virus reactivation increases. Nearly 10% of patients develop herpetiform skin lesions. It is recommended to screen for viral antibodies and use antiviral drugs prophylactically before treatment. In addition, about 8%-10% of patients develop mild reactions such as local erythema and induration after injection, which can be relieved by rotating the injection site. Headache, fatigue, transient low-grade fever, or gastrointestinal discomfort (such as nausea, diarrhea) are also common in the early stage of treatment. Most symptoms are gradually tolerated after continued treatment. If necessary, they can be relieved by adjusting the infusion rate or combining antihistamines.

Serious anilumab side effects:

The most significant risk of this drug is that it significantly inhibits the immune surveillance function, leading to serious opportunistic infections. Clinical data shows that about 3%-5% of patients develop pneumonia, urinary tract infection or tuberculosis relapse requiring hospitalization, and a few cases even develop Pneumocystis pneumonia or invasive fungal infection. If persistent high fever, shortness of breath, painful urination or abnormal skin abscesses occur during treatment, the drug must be stopped immediately and broad-spectrum anti-infective treatment must be initiated. In addition, about 2%-4% of patients develop immediate allergic reactions during or within hours after the infusion, manifesting as facial swelling, tongue and throat edema, hypotension or dyspnea. Severe cases may progress to anaphylactic shock, requiring immediate discontinuation of administration and injection of epinephrine for rescue.

Long-term drug use may increase the risk of cancer, especially lymphoma and skin cancer, and the mechanism is related to immune suppression leading to abnormal cells escaping surveillance. It is recommended to conduct tumor marker screening and skin examination every six months during treatment. It is worth noting that hepatitis virus carriers, active tuberculosis infections and patients with a history of malignant tumors need to be strictly excluded from clinical application. For patients who have experienced severe side effects, anilumab needs to be permanently discontinued and switched to another immunosuppressant. All patients receiving this drug should be monitored for signs of infection throughout the course of treatment and their immune status should be assessed before receiving live vaccines. If patients experience any abnormal symptoms, they need to communicate with their doctor promptly to weigh the benefits and risks of treatment.

Reference link: https://www.drugs.com/anifrolumab.html