Pfizer Announces Positive Top-Line Results for JAK Inhibitor in Ankylosing Spondylitis Trial

Ankylosing Spondylitis (AS) is a chronic, inflammatory disease that causes enthesitis or inflammation where the tendons, ligaments, and bones meet. This debilitating condition affects approximately 1% of the US population, and symptoms usually occur before 30. AS is responsible for impacting the quality of life by igniting severe chronic pain in the patient. On November 6th, Pfizer announced their Phase 3 clinical trial results in patients with AS using their flagship drug Xeljanz (Tofacitinib) [1].

Xeljanz – A First-of-its-Kind JAK Inhibitor

AS, which is characterized by activation of the inflammatory system, leads to the production of various pro-inflammatory factors. One of the major cellular pathways that drive the inflammation is the Janus kinase pathway. Xeljanz is a first-of-its-kind JAK inhibitor that has been approved by the FDA for various diseases like rheumatoid arthritis, adults with active psoriatic arthritis, among others. It has been studied in more than 50 clinical trials and is prescribed to more than 200,000 patients worldwide [2].

A3921120 Clinical Trial

A3921120 is a randomized double-blinded Phase 3 clinical trial aimed at studying the clinical safety and efficacy for their drug Xeljanz in patients diagnosed with AS who did not respond to non-steroidal anti-inflammatory therapy. This study enrolled 270 patients who received either the drug or placebo twice daily for 16 weeks. Eligible patients were then treated with the drug for additional 32 weeks. The clinical trial met the key primary and secondary endpoints as determined by Assessment in SpondyloArthritis International Society (ASAS) 20 and 40 response.

Approximately 56.4% of the patients receiving the drug reached the ASAS 20, which was significantly higher than the placebo group (29.4%). Further, 40.6% of the patients receiving the drug reached ASAS 40 response, while only 12.5% of patients in the placebo group met the criteria for ASAS 40 response. The major adverse events reported included upper respiratory tract infection, arthralgia, and headache, among others. These exciting findings will be presented during the virtual American College of Rheumatology (ACR)/Association of Rheumatology Professionals (ARP) Annual Meeting.

Michael Corbo, Chief Development Officer of Pfizer’s Global Product Development, said, “Ankylosing spondylitis is a debilitating condition, and its often progressive nature affects patients for most of their adult lives, limiting physical function and perceived health-related quality of life. We are proud to share these positive results from our Phase 3 investigational study for tofacitinib in adults with ankylosing spondylitis, and we believe they demonstrate Pfizer’s commitment to addressing unmet needs for those living with inflammatory conditions” [1].

Competition in the Market

With Xeljanz patent-protected from any biosimilar competition until 2025, Pfizer hopes to gain some ground in the market, which is already crowded by other pharmaceutical drug companies. Leading the way is AbbVie’s TNF inhibitor Humira and Amgen’s Enbrel, both of which have been approved for the treatment of AS. Further, Novartis’s IL-17 inhibitor, Cosentyx, has also been approved for the treatment of AS. With Xeljanz waiting to get FDA approval, these pharmaceutical giants are headed for a four-way race to capture the market [3].

By T. Chakraborty, Ph.D.

Related Article: Novartis’ Axial Spondyloarthritis Drug, Cosentyx Shines in Phase 3 Study

References

1. https://www.everydayhealth.com/ankylosing-spondylitis/guide/
2. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-positive-phase-3-study-results-xeljanz-r
3. https://www.mayoclinic.org/diseases-conditions/ankylosing-spondylitis/diagnosis-treatment/drc-20354813

Author

Tulip Chakraborty