Guselkumab's Efficacy, Safety Confirmed in Patients With Psoriatic Arthritis and Prior TNFi Exposure

Steve Cimino

December 02, 2021

A new study has established guselkumab (Tremfya) as both a safe and effective treatment option for psoriatic arthritis (PsA) in patients who had previously responded poorly to tumor necrosis factor inhibitors (TNFi).

Dr Laura Coates

"While the positive guselkumab benefit-risk profile observed through week 24 was maintained through 1 year, real-world evidence will further inform long-term guselkumab persistence in TNFi-inadequate response patients," writes Laura C. Coates, MBChB, PhD, of the University of Oxford, Oxford, United Kingdom, and her co-authors. The study was published in the Annals of the Rheumatic Diseases.

Previous studies indicated that the anti-interleukin-23p19 monoclonal antibody improved outcomes in patients with PsA, even after 1 year, but some uncertainty remained regarding the surprisingly similar level of effectiveness in biologic-naive and TNFi-treated patients. Guselkumab is approved for treatment of adults with moderate to severe plaque psoriasis who are candidates for systemic therapy or phototherapy and adults with active psoriatic arthritis.

Clarity on Guselkumab's Effectiveness in Certain Patients

"In previous studies that cemented guselkumab as a treatment option for PsA, what was odd was that the results were pretty comparable," Eric M. Ruderman, MD, professor of medicine and associate chief for clinical affairs in the Division of Rheumatology at Northwestern University in Chicago, Illinois, said in an interview. "We didn't really have a sense of how well it worked in patients who had failed other biologics, which is where you might expect a drug with a new mechanism to be used when it comes into a particular disease category.

Dr Eric Ruderman

"Not surprisingly, in this study, the overall response rate was a little less than the response rate in the other two trials," said Ruderman, who was not involved in the study. "You can't really compare across studies, but it does fit with what we might expect: People who've previously failed a TNF inhibitor might be a little less likely to respond to guselkumab, compared to someone who hasn't seen a TNF inhibitor."

When asked about potential follow-up studies, Ruderman noted that "the missing piece of the puzzle is that we still really have no way to compare this to other biologics. The next step would be to ask, in a single trial, what happens if you give some people TNF inhibitors and some people guselkumab? Just to try to give us context. Is this equivalent? Is it less effective? More effective? Where does it fit? Without that information, rheumatologists may struggle to figure out who is the right person for this drug and how often should they use it."

Study Details

To assess the efficacy and safety of guselkumab in patients who had previously taken TNFi but stopped because of inefficacy or intolerance, the researchers launched a randomized, double-blind study called COSMOS at 84 European sites from March 2019 to November 2020. The study's 285 patients ― 52% of whom were women, with an average overall age of 49 ― were assigned to two groups: guselkumab (n = 189) or placebo (n = 96). A total of 88% of all patients had used one TNFi prior; 12% had used two.

The guselkumab group received 100-mg injections at week 0, week 4, and then every 8 weeks through week 44; the placebo group received injections at weeks 0, 4, 12, and 20, followed by 100 mg of guselkumab at weeks 24, 28, 36, and 44. Patients with less than 5% improvement from baseline in both tender and swollen joint counts at week 16 qualified for early escape to "initiate or increase the dose of one permitted concomitant medication up to the maximum allowed dose at the physician's discretion." Ultimately, 88% of patients in the guselkumab arm and 83% of the placebo arm completed the study.

At 24 weeks, more than 44% of the guselkumab group achieved a 20% or greater improvement in American College of Rheumatology criteria (ACR20), compared with just under 20% of the placebo group, a difference of nearly 25% (95% CI, 14.1% to 35.2%; multiplicity-adjusted P < .001). At 48 weeks, nearly 58% of the guselkumab group had achieved ACR20; of the 51 patients in the placebo arm who started taking guselkumab at week 24, 55% achieved ACR20 by week 48.

Through 24 weeks, 80 patients in the guselkumab group (42%) and 46 patients in the placebo group (48%) experienced adverse events; only 3.7% and 3.1% developed serious adverse events, respectively. The most common adverse events in the guselkumab group at that point included nasopharyngitis (5%) and upper respiratory tract infection (4%), which occurred at a similar frequency (5% and 3%) in the placebo group.

The authors acknowledge their study's limitations, including imbalances in baseline characteristics such as gender and weight, as well as the COSMOS study being restricted to European patients and thus potentially limiting diversity. In addition, while the COVID-19 pandemic may have increased major protocol deviations near the end of the study, the authors note that "most were related to timing of study visits and did not impact efficacy."

The study was funded by Janssen, and six authors reported being employees of the company. The authors also acknowledge numerous potential conflicts of interest, including receiving consulting fees and research grants from various pharmaceutical companies, including Janssen. Ruderman is a consultant for AbbVie, Bristol-Myers Squibb, Eli Lilly, Novartis, Pfizer, and Janssen and served on the data safety monitoring committee for two other phase 3 guselkumab trials.

Ann Rheum Dis. 2021 Nov 24. doi: 10.1136/annrheumdis-2021-220991. Full text

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