Cosentyx Misses Primary Endpoint in Phase III Giant Cell Arteritis Trial

Novartis has reported that its anti-inflammatory drug Cosentyx did not achieve the main goal in a late-stage trial assessing its use in giant cell arteritis (GCA), an autoimmune disease involving inflammation of the arteries. The Phase III trial results place Novartis further behind AbbVie, whose JAK inhibitor Rinvoq was approved for GCA in April.
In the data shared on Thursday, Novartis confirmed that Cosentyx failed to significantly improve sustained remission at 52 weeks compared to placebo. The company also noted that secondary measures—including cumulative steroid dose and steroid-related toxicities—did not show statistically meaningful differences between the Cosentyx and placebo groups. However, Novartis stated that “numerically better outcomes” were observed with Cosentyx.

The results come from the Phase III GCAptAIN study, which enrolled more than 350 participants with newly diagnosed or relapsing GCA. Patients were assigned either 300 mg or 150 mg doses of Cosentyx alongside a 26-week steroid taper. The control group received placebo combined with a 52-week steroid taper.
Cosentyx functions by targeting and blocking interleukin-17A (IL-17A), a cytokine involved in initiating the body’s inflammatory response. Rinvoq, by contrast, works through inhibition of Janus kinases, which transmit signals from cytokines on the cell surface to the inside of the cell. Another approved treatment for GCA is Actemra, which inhibits the IL-6 receptor.
The disease, also referred to as temporal arteritis, is typically found in individuals over the age of 50 and is associated with symptoms such as fatigue, vision issues, and severe headaches. It can result in complications such as vision loss and potentially life-threatening aneurysms.
Novartis did not outline its regulatory plans for Cosentyx in GCA. The company stated that a complete analysis of the GCAptAIN study is still in progress and that it intends to share the full results “at a later date.”
In an April 16 communication to investors, Guggenheim Partners had listed the GCAptAIN trial outcome as one of the key developments to monitor from Novartis this year, as the company sought to expand in the inflammation treatment area.
AbbVie’s Rinvoq received regulatory approval for GCA following results that showed 46.4% of patients on the drug, combined with a 26-week steroid taper, achieved sustained remission from weeks 12 through 52. This compared to 29% of patients in the placebo group, with the difference being statistically significant.

Commenting on the outcome of the Cosentyx trial, Shreeram Aradhye, president of development and chief medical officer at Novartis, stated: “While the Phase III results… did not replicate the positive outcomes observed in the Phase II trial, we remain committed to continuing to drive scientific progress and deepening the understanding of immune-mediated diseases.”
The GCA market was valued at $1.1 billion in 2024 and is projected to grow to over $1.8 billion by 2035, according to analysis by the IMARC Group.