A mandated, nonmedical switch from adalimumab (Humira) to a biosimilar for psoriasis did not lead to a drop-off in drug retention, according to a Danish registry analysis.
A year after switching to a biosimilar, 92.0% of patients remained on treatment versus 92.1% of patients treated with adalimumab originator. Rates of discontinuation for any reason or for adverse events (AEs) did not differ between the two patient groups, although treatment with a biosimilar was associated with more dermatologic AEs.
The two groups also did not differ significantly with respect to change in disease severity, Nikolai Loft, MD, of the University of Copenhagen, and co-authors reported in JAMA Dermatology.
“These results suggest that the effectiveness of adalimumab biosimilar is similar to that of adalimumab originator,” the authors concluded. “A nonmedical switch from adalimumab originator to an adalimumab biosimilar does not appear to affect drug retention. However, switching to an adalimumab biosimilar might lead to more dermatologic AEs, although whether this is attributable to increased medical scrutiny remains unclear and warrants further study.”
A small, unrelated retrospective cohort study showed no difference in response rates for hidradenitis suppurativa (HS) treated with infliximab (Remicade) or the biosimilar infliximab-abda. Though limited, the findings suggest the biosimilar “is likely a reasonable treatment option for hidradenitis suppurativa,” reported Linnea Lackstrom Westerkam, BA, and colleagues at the University of North Carolina at Chapel Hill.
The two studies support the argument that biosimilars have effectiveness and safety comparable to that of originator drugs, wrote Mark Lebwohl, MD, of Mount Sinai Medical Center in New York City, in an accompanying editorial. However, he acknowledged that manufacturers of the originator drugs can legitimately argue that results obtained with biosimilars in rheumatoid arthritis (RA; initial indication for some biosimilars) do not necessarily predict results in psoriasis.
“The comorbidities of psoriasis differ from those of rheumatoid arthritis, and the numbers of patients studied are much smaller than the number required in pivotal trials so that rare or uncommon adverse effects may be overlooked,” Lebwohl wrote.
In the HS study, the small sample size could have explained the lack of difference in response rates, he continued. Additionally, pain scores were improved to a greater degree with infliximab originator, and a greater proportion of patients treated with the originator had improvement in disease status.
“There is already a growing body of evidence that biosimilars may be used successfully to treat psoriasis and hidradenitis suppurativa, and many clinicians are already convinced that biosimilars are equivalent to their originator drugs,” Lebwohl continued. “Inroads in the U.S. market, however, have been limited.”
“The complex interactions among pharmaceutical companies, insurers, and pharmacy benefit managers have unfortunately not resulted in savings for patients with psoriasis in the United States thus far. And there is a serious concern that the introduction of biosimilars 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,” he added.
In Denmark, a national guideline mandated a nonmedical switch from adalimumab to the biosimilars GP2017 and SB5 by November 2018 for all adults with psoriasis. GP2017 received approval on the basis of clinical trials in psoriasis, whereas SB5 received initial approval for RA, and the indication for psoriasis was added later, Loft and co-authors noted.
For the psoriasis study, investigators searched the Danish DERMBIO registry and identified 348 patients with moderate or severe psoriasis switched from ongoing treatment with adalimumab to one of two adalimumab biosimilars from Nov. 1, 2018 to May 1, 2019. A comparator group comprised 378 patients treated with adalimumab originator during May-November 2017. A total of 256 patients were included in both cohorts. The primary outcome was 1-year drug retention rates for the two cohorts.
The two cohorts had a mean age of 51-52, and men accounted for 72% of the patients. In the biosimilar cohort, 28 patients (8.0%) stopped treatment within 12 months: 12 because of lack of effectiveness, nine because of AEs, and seven for other reasons. In the adalimumab originator cohort, 30 patients (7.9%) stopped treatment: 16 because of lack of effectiveness, seven because of AEs, and seven for other reasons.
The cohorts had virtually identical 1-year retention rates, reflected in a hazard ratio (HR) of 1.02 for all-cause discontinuation for the biosimilar group versus the originator group (95% CI 0.61-1.70, P=0.94). The proportion of patients who discontinued because of lack of effectiveness also did not differ significantly between the two groups (HR 0.82, 95% CI 0.39-1.73, P=0.60), nor did the rates of discontinuation because of AEs (HR 1.41, 95% CI 0.52-3.77, P=0.50).
The HS study comprised 34 patients treated for at least 10 weeks with infliximab (n=20) or infliximab-abda (n=14). The primary outcome was HS clinical response, defined as at least a 50% decrease in inflammatory nodules with no increase in the number of abscesses or draining sinuses. In the biosimilar group, 10 (71%) patients met criteria for clinical response as compared with 12 (60%) patients in the infliximab group, Westerkam and co-authors reported.
The Biological Treatment in Danish Dermatology (DERMBIO) registry has relationships with AbbVie, Eli Lilly, Almirall, UCB, Novartis, Janssen, and LEO Pharma.
Loft disclosed relationships with Eli Lilly and Janssen.
Lebwohl disclosed relationships with AbbVie, Amgen, Arcutis, Avotres, Boehringer Ingelheim, Dermavant, Eli Lilly, Incyte, Janssen, Ortho Dermatologics, Regeneron, UCB, Aditum Bio, AnaptysBio, Almirall, Aristea, Arrive Technology, BiomX, Bristol Myers Squibb, Cara Therapeutics, Castle Biosciences, Corrona, Dr. Reddy’s, Evelo, Evommune, Facilitate International Dermatologic Education, Forte, Foundation for Research and Education in Dermatology, Helsinn, LEO Pharma, Meiji, Mindera, Pfizer, and Verrica.