Despite receiving Food and Drug Administration (FDA) approval for the treatment of non-radiographic axial spondyloarthritis (nr-axSpA) before Novartis’s Cosentyx (secukinumab), Eli Lilly’s Taltz (ixekizumab) will not overthrow Cosentyx as the premiere anti-interleukin (IL) 17 biologic in the axSpA space. Taltz is forecast to achieve 2028 sales of $239m across the seven major markets (7MM*), whereas Cosentyx is predicted to earn $565m in the same period, according to GlobalData, a leading data and analytics company.

Antoine Grey, Senior Immunology Analyst at GlobalData, comments: “Taltz’s nr-axSpA approval was highly anticipated due to its approval in ankylosing spondylitis in August 2019, both of which fall under the disease umbrella of axSpA, and the fact that the only biologic treatment available to nr-axSpA patients until now was UCB’s Cimzia (certolizumab pegol). This is in contrast to the EU, where Cosentyx has already been approved for nr-axSpA but Taltz has yet to receive approval.”

The FDA’s decision to approve Taltz was based on data from its COAST-X study, which looked to assess the proportion of patients achieving a 40% improvement in symptoms when measured by the Assessment of SpondyloArthritis International Society response criteria (ASAS40) at Week 16 and Week 52. The results demonstrated that 35% of patients treated with Taltz achieved ASAS40 at Week 16, compared to 19% treated with placebo. At Week 52, 30% of patients treated with Taltz achieved ASAS40, compared to 13% on placebo.

Grey continues: “Taltz beating Cosentyx to approval may not be such a blessing for Lilly due to the prospect of launching the drug during the ongoing COVID-19 pandemic, which is likely to hamper efforts to spread awareness of the drug at conferences, at face-to-face sales pitches, and fewer in-person rheumatologist appointments could all lead to fewer new prescriptions.”

With both drugs being anti-IL-17 biologics, Taltz and Cosentyx suffer from the same drawback of being contraindicated in patients with irritable bowel disease (IBD), a common comorbidity of axSpA, meaning Lilly will need to work hard to claw patient share from the same patient demographic as Novartis.

Grey concludes: “Despite Taltz having a single dosage strength of 80mg compared to Cosentyx’s 1150mg and 300mg dosages, a factor key opinion leaders (KOLs) interviewed by GlobalData raised as a point of confusion to patients, Cosentyx has already established itself as the go-to anti-IL-17 treatment in axSpA.”

*7MM: US, France, Germany, Italy, Spain, UK and Japan