LONDON (FRONTLINE MEDICAL NEWS) – Long-term treatment with the interleukin 17A inhibitor secukinumab showed suggestive evidence of inhibiting structural progression of spinal disease in 168 patients with ankylosing spondylitis, the first time any evidence for an effect like this has been seen with a biologic drug or any other agent used to treat ankylosing spondylitis.

However, the effect occurred in uncontrolled, 2-year open-label treatment of patients originally enrolled in one of the secukinumab pivotal trials, and the analysis did not include comparison against a historical control group, caveats that demand confirmation of this effect in additional studies, Dr. Jürgen Braun said at the European Congress of Rheumatology.

In a second, unrelated study, the oral Janus kinase inhibitor tofacitinib showed promising efficacy for controlling clinical symptoms in patients with active ankylosing spondylitis (AS) during 12 weeks of treatment in a placebo-controlled, dose-ranging phase II study.

The open-label secukinumab extension study involved patients who had been enrolled in the MEASURE 1 study, one of the pivotal trials that had established secukinumab as safe and effective for improving the clinical status of patients with active AS. The primary endpoint of MEASURE 1 had been the percentage of patients achieving at least a 20% improvement in their Assessment of Spondyloarthritis international Society ( ASAS20 ) response after 16 weeks of treatment ( New Engl J Med. 2015 Dec 24;373[26]:2534-48 ).

Based in part on these data the Food and Drug Administration approved secukinumab (Cosentyx) for the treatment of ankylosing spondylitis in January 2016. The new data reported by Dr. Braun assessed the level of spinal pathology in a subgroup of the MEASURE 1 patients when measured by radiography using the modified Stoke Ankylosing Spondylitis Spine Score ( mSASSS ) at baseline and after 104 weeks on secukinumab treatment.

Patients in MEASURE 1 who began on active treatment received 10 mg/kg intravenous secukinumab for 4 weeks, followed by subcutaneous dosages of either 75 mg or 150 mg every 4 weeks for 104 weeks. His analysis also included some patients who entered MEASURE 1 in the placebo group and then switched to open-label, subcutaneous secukinumab treatment after 16 or 24 weeks on placebo.

Analysis of 168 patients who started on intravenous secukinumab and later received any subcutaneous secukinumab treatment out to 104 weeks showed an average increase in mSASSS of 0.30 after 104 weeks when compared against their baseline scores, reported Dr. Braun, professor and medical director of the Ruhr Rheumatology Center of the University of Bochum, Germany.

Among an additional 89 patients who began in the placebo group and then switched to subcutaneous secukinumab, the average change in mSASSS from baseline to 104 weeks was 0.54. By comparison, Dr. Braun noted that AS patients treated with a tumor necrosis factor inhibitor have shown 2-year progression in their mSASSS of about 0.8-0.9, and AS patients not treated with an active biologic drug have shown 2-year mSASSS progression of about 1.0.

A second analysis of the data reported by Dr. Braun showed that among the 168 patients treated for the full 104 weeks with secukinumab about 80% showed no mSASSS progression, but about 20% did have some level of detectable mSASSS progression.

The phase II study of tofacitinib (Xeljanz) randomized 208 patients with active AS to either tofacitinib at daily dosages of 2 mg bid, 5 mg bid, 10 mg bid, or placebo. The study’s primary endpoint was their ASAS20 response after 12 weeks that underwent a Bayesian Emax model analysis to estimate incremental efficacy when compared against placebo.

The primary efficacy analysis showed the greatest EmaxASAS20 response among patients treated with 5 mg bid daily, 63%, which was about 23% above the placebo level, reported Dr. Désirée van der Heijde , professor of rheumatology at the Leiden University Medical Center, The Netherlands. The absolute ASAS20 response rate of the 52 patients randomized to this tofacitinib dosage was about 81%, about 40% higher than the response rate seen in the 51 patients in the placebo arm.

All dosages of tofacitinib tested were well tolerated, with safety data similar to what has previously been shown for tofacitinib, a drug that has Food and Drug Administration approval for treating rheumatoid arthritis.

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