In April, FDA approved infliximab-abda (Renflexis, Samsung Bioepis), the second biosimilar for reference biologic infliximab (Remicade, Janssen) after biosimilar infliximab-dyyb (Inflectra, Pfizer). As with infliximab and infliximab-dyyb, infliximab-abda is approved for adult Crohn disease, pediatric Crohn disease, ulcerative colitis, rheumatoid arthritis (RA), ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis. How clinicians choose which agent to use may set the tone for future cases in which more than one biosimilar is approved for a biologic.
The infliximab agents are currently not interchangeable by FDA standards, as the agency released draft guidance on the requirements for that designation only last January. But the approval process for biosimilars should put health providers at ease when making clinical decisions, said James G. Stevenson, PharmD, FASHP, professor in the department of clinical pharmacy at University of Michigan College of Pharmacy in Ann Arbor.
“From an efficacy and safety perspective, there appears to be no difference between these three. FDA approval means there is no clinically significant difference between biosimilars and reference products,” Stevenson said.
Switching trials comparing infliximab with infliximab-dyyb, presented at the American Gastroenterological Association’s Digestive Disease Week in May, showed no significant difference between them. Yet some meeting attendees worried about the possibility of patients outside the trial setting developing significant neutralizing antibodies when switched.
“It’s a theoretical risk, but it hasn’t been shown in studies to date,” Stevenson said, noting that antibodies could develop with any biologic. He acknowledged that some gastroenterologists may be concerned because the studies for infliximab were not specifically for gastrointestinal (GI) indications. Rather, they were for RA and ankylosing spondylitis, and the results extrapolated out.
“The agencies don’t require studies for every indication. If a biosimilar is studied in one of the sensitive indications, looks the same as the reference product, and has the same mechanism of action, they extrapolate the data to the other disease states,” Stevenson explained. “[Some gastroenterologists] would like to see studies for GI indications. But I think as people get more comfortable using biosimilars, they’ll grow in confidence in the principle of extrapolation.”
If providers can expect the same safety and efficacy from infliximab and its biosimilars—or any reference and its biosimilars—the choice may come down to matters of practicality, said Stevenson.
“It’s likely we’ll see new biosimilars where there are already other biosimilars approved, so people making purchasing or formulary decisions will have to decide: If there is more than one, how do you pick which one?” Stevenson said. “There are some nuances to consider, like dosage forms. Then there are things like whether the label is clear. Will it lead to medical errors? Is its bar code easily readable by our bar code systems?”
For the full article, please visit www.pharmacytoday.org for the July 2017 issue of Pharmacy Today.