MAUI, HAWAII (FRONTLINE MEDICAL NEWS) – The most important development within the past year in the treatment of ankylosing spondylitis was the Food and Drug Administration approval of secukinumab (Cosentyx) as the first non-tumor necrosis factor inhibitor biologic for this condition – but the interleukin-17A inhibitor is not going to immediately step into a role as a first-line therapy, Dr. Eric M. Ruderman predicted at the 2016 Rheumatology Winter Clinical Symposium.

“In all likelihood nobody’s going to use this as a first-line drug right out of the gate. It’s a drug you’re going to potentially go to in people who haven’t responded to the things that you’ve been comfortable using for the last 10 or 15 years. So the big practical issue becomes, ‘How does secukinumab perform in TNF inhibitor-naive patients versus prior TNF inhibitor inadequate responders?’ ” according to the rheumatologist, who is professor of medicine at Northwestern University in Chicago.

This question has been addressed in secondary analyses of the pivotal phase III MEASURE 1 and MEASURE 2 trials which have been presented at the annual European League Against Rheumatism and American College of Rheumatology meetings. The bottom line was that the therapeutic response rate in both trials was markedly lower in TNF inhibitor inadequate responders than in TNF inhibitor-naive subjects.

“But there still is a significant response rate in the inadequate responders. It’s clearly better than placebo. So this is a drug that may have a role in your practice at the point where patients have failed on one or two anti-TNF biologics,” according to Dr. Ruderman .

The difference between MEASURE 1 and MEASURE 2 is that MEASURE 1 entailed three intravenous loading doses of the biologic at 2-week intervals before switching to monthly subcutaneous dosing, while MEASURE 2 featured subcutaneous loading doses given weekly for 4 weeks before moving to monthly administration. Interestingly, the FDA approval of secukinumab at 150 mg doesn’t call for a loading dose, even though both pivotal trials relied on them, the rheumatologist observed.

At 16 weeks in MEASURE 1, 66% of TNF inhibitor-naive subjects on secukinumab 150 mg had at least a 20% improvement from baseline in ankylosing spondylitis signs and symptoms, or Assessment of Spondyloarthritis International Society (ASAS) 20, compared with 46% of TNF inhibitor inadequate responders. The week 16 ASAS 20 rate in MEASURE 2 was 68% in TNF inhibitor-naive patients and 50% in those with a prior inadequate response to TNF inhibitor therapy.

How should rheumatologists expect secukinumab to perform in daily clinical practice? In the 181 ankylosing spoindylitis patients who completed 52 weeks in the MEASURE 2 extension study, 74% of those on secukinumab at 150 mg had an ASAS 20 response. In both trials, the secukinumab side effect profile was “reasonably clean,” in Dr. Ruderman’s view, with serious adverse events that were similar to placebo.

Serial MRI scans showed rapid resolution of bone marrow edema and inflammation by 16 weeks, an effect sustained through 52 weeks.

The big unanswered question is whether secukinumab prevents radiographic progression of the disease. Serial cervical and spinal X-rays rated using the modified Stoke Ankylosing Spondylitis Spinal Score showed a mean increase of just 0.30 points at 2 years from a baseline of 10.22, with 80% of patients demonstrating no change over time. But there were no untreated controls for comparison in this analysis, so it’s not possible to say whether the drug actually slowed disease progression or that’s the natural history of disease in those subjects, Dr. Ruderman noted.

Effect of NSAID dosing frequency on progression

On the topic of preventing radiographic progression in ankylosing spondylitis, the rheumatologist highlighted a prospective study presented at last year’s EULAR meeting and published online last summer ( Ann Rheum Dis. 2015 Aug 4. doi: 10.1136/annrheumdis-2015-207897 ) that demonstrated that continuous use of diclofenac didn’t do any better at preventing radiographic spinal disease progression than on-demand use of the nonsteroidal anti-inflammatory drug (NSAID) over the course of 2 years.

“There’s been a lot of noise in the ankylosing spondylitis community about the potential benefit of NSAIDs in preventing structural progression. Previous information suggested that staying on them continuously actually reduced radiographic progression. This diclofenac study has shaken things up a little. It raises the question of whether there is any added benefit for NSAIDs in terms of structural progression,” he commented.

Current ACR/SAA/SPARTAN guidelines, which predate the study, feature a conditional recommendation that patients with active ankylosing spondylitis stay on continuous NSAID therapy.

Secukinumab is also approved for treatment of psoriasis and psoriatic arthritis.

Dr. Ruderman reported serving as a consultant to and/or receiving research grants from numerous pharmaceutical companies, including Novartis, which markets secukinumab.