April 2025

Below is in response to the inquiry: I have prescribed my patient Humira as they have severe Rheumatoid arthritis and have already failed conventional DMARDs: methotrexate, plaquenil, and sulfasalazine. The patient's TB blood test came back positive, although the patient does not have any symptoms and their chest Xray is clear. The patient was started on Isoniazid, and has already been on it for 2 weeks. The patient wants to begin initiating Humira as she is having a bad joint flare, can she be on Isoniazid and Humira at the same time?

This patient is likely to have latent Tb infection (LTBI) based on the positive blood test and negative chest X-ray with no signs or symptoms. According to Humira’s package insert, anti-Tb therapy should be initiated, as treatment of LTBI prior to therapy with Tumor Necrosis Factor (TNF)  blocking agents has shown to reduce the risk of Tb reactivation during therapy.1

According to Iannone et al, most guidelines recommend waiting at least 1 to 2 months after starting treatment of LBTI before starting treatment with biologics.2 This evidence comes from the observation that initiation of anti-TNF-α therapy after 1 month of Tb treatment significantly reduced the risk of Tb activation in Rheumatoid Arthritis patients with positive LBTI. However, it is preferable to wait 1 additional month to avoid side effects of anti-TNF-α with isoniazid, which occur mainly within the first 2 months.

Therefore, it is not recommended to begin Humira therapy at this moment, as it has only been two weeks since the patient started isoniazid treatment. At this time, the patient should continue to be monitored for signs and symptoms of infection, and wait until at least 2 months after isoniazid treatment before starting Humira.

Reference: 

1. Humira. Package insert. Abbvie Inc; February 2024.

2. Iannone F, Cantini F, Lapadula G. Diagnosis of latent tuberculosis and prevention of reactivation in rheumatic patients receiving biologic therapy: international recommendations. Journal of Rheumatology Supplement. 2014;91(0):41-46. doi:10.3899/jrheum.140101