IV Secukinumab Trials Hit Primary Endpoints in PsA, AxSpA

SAN DIEGO — Monthly use of intravenously administered secukinumab (Cosentyx) proved its efficacy over placebo in treating psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) in two industry-sponsored, randomized, double-blinded, phase 3 trials of the drug's second and newly approved route of administration.

The studies of the human monoclonal antibody secukinumab, an interleukin-17 inhibitor, were presented at the annual meeting of the American College of Rheumatology. A subcutaneously injectable formulation of the drug is available, and the Food and Drug Administration approved the IV form for the conditions in October, although at a recommended lower monthly dose than the new trials examined.

In the PsA trial, 191 patients took IV secukinumab, and 190 took placebo. For the primary endpoint, the percentages who reached at least a 50% improvement in American College of Rheumatology response criteria (ACR 50) at 16 weeks were 31.4% and 6.3%, respectively (P < .0001).

In the axSpA trial, 264 patients took IV secukinumab, and 262 took placebo. The primary endpoint, at least a 40% improvement in Assessment of the Spondyloarthritis International Society response criteria (ASAS 40), was met at 16 weeks by 40.9% and 22.9%, respectively (P < .0001).

"Both studies appear to present clear efficacy of IV route administration of secukinumab with no clear increase in safety signals," consultant rheumatologist Nicola Goodson, MBChB, PhD, of Aintree University Hospital in Liverpool, England, said in an interview.

"Offering IV administration as an option to patients is helpful," added Dr. Goodson, who was not involved with the study but is familiar with its findings.

As Dr. Goodson explained, secukinumab "was the first IL [interleukin]-17 inhibitor used to treat spondyloarthropathies, and we have been using subcutaneous secukinumab to treat psoriasis, psoriatic arthritis, and axial spondyloarthritis/ankylosing spondylitis since 2016 in the U.K. Our experience with this medication has been good with similar efficacy to anti-TNF [tumor necrosis factor] therapy in axial spondyloarthritis. The medication is generally well-tolerated, and the subcutaneous pen injection device is easy for patients to use."

However, IV treatment may speed up onset of action, she said, and it may be useful in situations when compliance is a challenge.

PsA trial details

In the PsA trial, known as INVIGORATE-2, researchers recruited patients who met the CASPAR criteria for active PsA with symptoms for ≥ 6 months, and had ≥ 3 tender joints out of 78 joints and ≥ 3 swollen joints out of 76.

Participants with a mean age of 48, including 55% females, were randomized 1:1 to receive placebo or secukinumab (6 mg/kg at baseline followed by 3 mg/kg every 4 weeks). Those in the placebo group were switched to the same monthly doses of secukinumab at 16 weeks.

"Patients who switched from the placebo had a similar increase of efficacy as the original treated group," rheumatologist Alan J. Kivitz, MD, of the Altoona Center for Clinical Research, in Duncansville, Penn., said in his presentation at the meeting. Specifically, at 52 weeks, the groups had similar ACR 50 response rates: 58% with secukinumab and 64% with placebo-to-secukinumab.

The fact that patients in the original placebo group who received 3 mg IV doses without 6-mg loading doses achieved ACR response rates similar to those who took secukinumab during the whole trial "could suggest that the IV loading dose may not be required. This would need to be explored in a randomized head-to-head study, but it's an interesting observation that may reduce costs and exposure to higher doses of medication at the start of treatment," Dr. Goodson said.

Among the patients who received secukinumab at any point in the study, 63% had a treatment-emergent adverse event, including 5.9% with serious events. One death was reported in the placebo group before week 16. No other deaths were reported.

AxSpA trial details

In the axSpA trial, called INVIGORATE-1, researchers recruited people aged ≥18 years with a diagnosis of active radiographic axSpA according to modified New York criteria or nonradiographic axSpA according to ASAS criteria, and all had inflammatory back pain for ≥6 months with an onset before age 45. They were randomized at a 1:1 ratio to receive IV secukinumab (6 mg/kg loading dose, followed by 3 mg/kg every 4 weeks) or placebo for 16 weeks. At that point, the placebo group switched to the same monthly doses of IV secukinumab.

Participants had a mean age of about 39, and about one-third were female.

Following the statistical superiority in ASAS 40 response rates seen with IV secukinumab at week 16, patients who from there switched from placebo to IV secukinumab achieved comparable ASAS 40 response rates to those of patients originally randomized to secukinumab by week 24, reaching 66.8% for those on secukinumab the whole time and 74.9% for those who switched.

Secondary outcome measures were similar in both groups at week 52.

Among all patients who took secukinumab – the percentage with any adverse event was 63.2%, and 6% had a nonfatal adverse event deemed serious. There was one death during secukinumab treatment not suspected to be related to treatment.

In a presentation about the axSpA study findings, Atul Deodhar, MD, of Oregon Health & Science University, noted that "having an IV biologic available in the U.S. has some advantages. There are certain insurance providers such as Medicare where it is more economical for the patient to have an IV drug available."

Dr. Deodhar also noted that in October the FDA approved a recommended lower dose for the IV treatment than in the study: 1.75 mg/kg instead of 3 mg/kg following the loading dose. That's because the 3 mg/kg dose caused blood levels to be higher than those in the subcutaneous form, he said.

The FDA made the same dose recommendation for PsA.

Study limitations

Dr. Goodson, the U.K. consultant rheumatologist, noted a limitation of the trials: "It would have been interesting to compare IV to subcutaneous route secukinumab." Still, the findings suggest that "the safety and efficacy of IV administration appears comparable," she said.

"IV administration will have associated costs of attending hospital or infusion clinics," she added, "and the cost of additional staff and administration need to be considered."

Novartis, the maker of secukinumab, funded both studies. The PsA study authors report multiple relationships with industry, and some, such as Dr. Kivitz, have connections to Novartis. The axSpA study authors also report multiple relationships with industry, and some, such as Dr. Deodhar, have connections to Novartis. Some authors of both studies are Novartis employees. Dr. Goodson disclosed financial relationships with UCB and AbbVie.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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