Taltz Receives FDA Approval for Treatment of Psoriatic Arthritis

Taltz (ixekizumab), manufactured by Eli Lilly and Company, was originally approved by the U.S. FDA in March 2016 for the treatment of adults with moderate-to-severe plaque psoriasis, who are also candidates for phototherapy or systemic therapy. However, in December 2017, the FDA (Food and Drug Administration) approved Taltz for the treatment of adults with active psoriatic arthritis. Taltz for psoriatic arthritis will come as an 80 mg/mL injection to be taken on its own or with a traditional DMARD (disease-modifying antirheumatic drug) like methotrexate.

Research behind Taltz (ixekizumab)

The FDA primarily based its recommendation on the results of two double-blind, placebo-controlled, randomized Phase 3 clinical trials, known as SPIRIT-P1 and SPIRIT-P2. Both studies combined involved nearly 700 individuals with active psoriatic arthritis for at least six months, and compared the outcomes of individuals given Taltz to the outcomes of those given a placebo. SPIRIT-P1 included individuals who had never been treated with a biologic DMARD, while SPIRIT-P2 included individuals who had previously tried, and failed to see a response, with either one or two TNF inhibitors (tumor necrosis factor inhibiting medication).

The primary efficacy endpoint of these studies was the proportion of those achieving a 20% reduction in a composite measure of disease activity. This measurement is called an ACR20, and is defined by the American College of Rheumatology (ACR). At the 24-week mark, 58% of individuals in SPIRIT-P1 and 53% of individuals in SPIRIT-P2 achieved ACR20, compared to 30% and 20% of individuals, respectively. This was a statistically significant and clinically relevant difference between the treatment and placebo groups.

How Taltz (ixekizumab) works

Taltz is a monoclonal antibody that inhibits the IL-17 receptor by binding to interleukin 17A (IL-17A) cytokine. This allows Taltz to interfere in an immune system-related pathway, and prevents the release of pro-inflammatory cytokines and chemokines that can lead to the inflammatory response-related symptoms of psoriatic arthritis, such as joint pain.

Possible side effects

The most common side effects experienced by those taking talks were nausea, upper respiratory tract infections, injection site reactions, and tinea (fungal) infections. The safety profile of Taltz when used to treat psoriatic arthritis was found to be consistent with the safety profile of Taltz used to treat plaque psoriasis. As is the case with many immune system-affecting medications, individuals taking Taltz must be monitored for signs of serious infection while taking the medication. Individuals taking Taltz should also be monitored for signs of hypersensitivity (allergic) reactions, as well as be tested for tuberculosis infection before starting the medication.¹