Two Studies Add to Knowledge Base of Biosimilar Use in Psoriasis, HS

Doug Brunk

April 29, 2021

A cohort study of psoriasis patients in Denmark found that a nonmedical switch from brand name adalimumab to adalimumab biosimilars was not associated with drug retention at 1 year. And another study, a small, single-center retrospective study of patients with hidradenitis suppurativa (HS), found that administration of infliximab and biosimilar infliximab were associated with similar and significant improvement in disease.

Both studies were published online in April in JAMA Dermatology and add to mounting evidence that biosimilars may be interchangeable in certain dermatologic conditions.

"Biosimilars are an exciting innovation in the field," Joseph Zahn, MD, assistant professor of dermatology at George Washington University, Washington, said in an interview. "Their efficacy and price point will allow patients greater access to effective treatment." To date, biosimilars approved in the United States that could be prescribed by dermatologists include those for rituximab, etanercept, adalimumab, and infliximab.

In the trial from Denmark, Nikolai Loft, MD, of the University of Copenhagen and colleagues evaluated outcomes following a mandatory medical switch from the brand name adalimumab, referred to as adalimumab originator, to adalimumab biosimilars among 726 individuals who were enrolled in a Danish nationwide registry of patients treated with biologics since 2007. The primary outcome was 1-year drug retention in patients switching to adalimumab biosimilars compared with patients treated with adalimumab originator.

The study population consisted of 348 patients with at least 2 years of exposure to adalimumab who had switched from originator to adalimumab biosimilars (a mean age of 52 and 72% male) and 378 patients who served as the adalimumab cohort (a mean age of 51 and 71% male). When the researchers compared the 1-year drug retention rates between the adalimumab biosimilar cohort and the adalimumab originator cohort, the rates were similar (92% vs. 92.1%, respectively).

The hazard ratios for other outcomes were similar as well. Specifically, the crude hazard ratios were 1.02 (P = .94) for all causes of drug discontinuation, 0.82 (P = .60) for insufficient effect, and 1.41 (P = .50) for adverse events (AEs) in the adalimumab biosimilar cohort, compared with the adalimumab originator cohort.

"Overall, results for any AEs were contradicting, but certain AEs were more prevalent in the adalimumab biosimilar cohort," the authors wrote. Dermatologic AEs and AEs in the "other" category "were more prevalent, which could be attributable to more patients experiencing injection site reactions as a result of larger volumes and differences in excipients and syringes in the adalimumab biosimilars and the adalimumab originator." Other potential explanations they offered were the nocebo effect and greater awareness of AEs among practitioners and patients.

"This study concludes that, when switched to a biosimilar medication, patients do not have worse control of their psoriasis nor do they switch to other medications," Zahn, who was asked to comment about these results, said in the interview. "However, there was a trend toward a higher number of side effects in the biosimilar group. The main takeaway point from this study is that biosimilars of adalimumab seem to be relatively interchangeable in patients with psoriasis without loss of efficacy or significant increase in side effects that lead to a medication change for the patient."

The researchers acknowledged certain limitations of their study, including the fact that it was limited to Danish patients and that individual AEs could not be examined. "Moreover, the surveillance of AEs is not as vigilant as in clinical trials, and AEs are most likely underreported," they wrote. "Although no major differences were found when switching from adalimumab originator to adalimumab biosimilar versions, it was not possible to assess the performance of individual adalimumab biosimilar versions in this study."

In the second study, Christopher Sayed, MD, associate professor of dermatology, University of North Carolina, Chapel Hill, and colleagues retrospectively evaluated the effectiveness of infliximab-abda versus infliximab administration in the treatment of 34 patients with HS who were cared for at the university's dermatology clinic. Patients were treated with either agent for at least 10 weeks. The infliximab treatment group consisted of 20 patients with a mean age of 42 years who were mostly female (17; 85%), while the infliximab-abda treatment group included 14 patients with a mean age of 36 years who also were mostly female (13; 93%).

Both groups received loading doses of 10 mg/kg at weeks 0, 2, and 6, and treatment was continued with a maintenance dose administered every 4-8 weeks. The patients were followed between February 2016 and June 2020 and the primary outcome measure was Hidradenitis Suppurative Clinical Response (HiSCR), which was defined as at least a 50% decrease in inflammatory nodule count without any increase in the number of abscesses or draining sinuses.

The researchers found that 71% of patients in the infliximab-abda treatment group achieved a HiSCR, compared with 60% of their counterparts in the infliximab treatment group, a difference that did not reach statistical significance (P = .47). Three patients in the infliximab treatment group experienced AEs, compared with none in the infliximab-abda treatment group.

"The data are promising," Zahn said. "Although this is a small study with a limited number of patients, it suggests that this particular biosimilar may be a reasonable or possibly even equivalent alternative to infliximab. A larger, prospective trial will be needed before we can be sure the results are equivalent."

Sayed and colleagues noted certain limitations of their study, including the retrospective design and the use of concomitant medications by some participants. "There is also a risk of selection bias because copay and medication assistance programs are not available for infliximab-abda for patients with HS," they wrote.

In an editorial accompanying the two studies, Mark Lebwohl, MD, professor of dermatology, Icahn School of Medicine at Mount Sinai, New York, wrote that the introduction of biosimilars have been justified by "the hope that lower costs" will increase availability of treatments to patients with moderate to severe psoriasis. "Inroads in the U.S. market, however, have been limited," he added, and there is concern that they "may be used to prevent access to newer interleukin-17 blockers and interleukin-23 blockers for which biosimilars are available and that do not carry the boxed warnings found on tumor necrosis factor blockers."

Loft reported receiving personal fees from Eli Lilly and Janssen outside of the submitted work. Many of his coauthors reporting having numerous financial conflicts of interest with the pharmaceutical industry. The HS study was supported by a public health service research award from the National Institutes of Health. Sayed reported receiving personal fees or personal fees paid to the institution from AbbVie, Novartis, Chemocentryx, GlaxoSmithKline, Incyte, InflaRx, and UCB. No other disclosures were reported. Lebwohl disclosed receiving research funds from companies including AbbVie, Amgen, Boehringer Ingelheim, Eli Lilly, and Incyte; and receiving personal fees from multiple companies, outside of the submitted work. Zahn reported having no disclosures.

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

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