Research Examines Self-administered Humira Biosimilars

Patients with rheumatoid arthritis (RA) may have difficulty self-administering Humira (adalimumab) or its biosimilars owing to arthritis impairment, so it is important for these patients to have a variety of options that may improve tolerability and adherence. Investigators in two recent studies reported they have successfully demonstrated the value of biosimilar versions of Humira used in prefilled pensand autoinjector devices .

In one of these studies, lead author Roy M. Fleischmann, M.D., and his co-investigators sought to establish whether patients with active RA could correctly and successfully use prefilled pens filled with Abrilada, a biosimilar of Humira that was approved in 2019 but isn’t on the market yet in the United States. Fleischmann is a clinical professor in the Department of Internal Medicine at theUniversity of Texas Southwestern Medical Center in Dallas.

Studies havebeen done to establish the viability of patient switching from prefilled syringesto prefilled pens, but Fleishmann wrote that the reported data were based on “subjective health care provider preference surveys.”

He and his investigative team were able to establish that with adequate instruction, patients with RA could safely and successfully self-administer Abrilada with prefilled pens.

The investigation was a sub-study within a larger phase 3 trial of Abilada versus Humira to determine equivalence in efficacy, safety, immunogenicity, pharmacokinetics, and pharmacodynamics in patients with RA. By week 52 of the study, all patients had been switched to Abrilada, and at that point, 50 participants (74% women; average age 55) began injections with prefilled pens, for the sub-study.

After instruction, patients (or designated caregivers) were observed self-injecting with prefilled pens on visits to clinical sites. Prefilled pen devices were collected to determine whether full dosage had been delivered.

The delivery system success rate was 100% (meeting the predetermined end point) and involved 294 injections over the 10-week sub-study term. Further, the vast majority (95.9%) of patients elected to continue using prefilled pens, which in a previous study involving Humira had shown a patient-perceived reduction in injection-site pain versus prefilled syringes.

Fleischmann reported that none of the patients expressed complaints about the PFP. “Nearly all participants who completed the sub-study elected to continue study treatment using prefilled pen injections,” he wrote.

Whereas prefilled pen devices may offer increased convenience for patients, autoinjectors may offer more flexibility for patients, avoid the problem of needle phobia, and lower the risk of incorrect administration, wrote lead author Ahad Sabet, M.D., an internist affiliated with St. Mark’s Hospital in Salt Lake City, Utah, and a researcher with PRA Health Sciences, which is also in Salt Lake City.

In a separate study, Sabet and his co-investigators sought to establish the bioequivalence, safety, and tolerability of Idacio, a biosimilar of Humira, when used in autoinjfectors or prefilled syringes. Idacio is approved for use in the European Union but not yet in the United States.

The study involved abdominal and thigh injections of a single 40 mg/0.8 mL dose of Idacio in a healthy population of 216 volunteers, who were randomized equally to an autoinjector or prefilled syringes group. Co-primary end points were drug concentrations over time. In this study, the average age of participants was 31 and roughly 66% were men.

Sabet and his investigative team reported that drug concentrations fell within predefined equivalence margins. “Mean serum concentration-time profiles were similar following injection via AI (autoinjector) or PFS (prefilled syringes),” he wrote, and treatment emergent adverse events also were comparable between study cohorts.

Sabet and his co-investigators observed a slight inverse relationship between body weight and drug exposure in the study, although this was similar between devices and previously was observed for Humira. No difference was observed for point of injection, whether abdomen or thigh. They concluded that autoinjector worked as well as prefilled syringes in this study.

“Having a choice of self-injection devices can help patients to select a device that addresses their individual challenges and lifestyles, with some patients preferring a PFS and others electing to use an AI,” Sabet wrote. “This may increase patient tolerance of self-injection and potentially improve adherence to treatment.”

Studies have shown that patients in advanced stages of RA with reduced dexterity due to psoriatic arthritis and ankylosing spondylitis tend to prefer autoinjectors over prefilled syringes, although one of the limitations of this study was that it was in a healthy population of volunteers and inflammation-related dexterity issues could not be studied, Sabet concluded.