The U.S. Food and Drug Administration (FDA) has approved Renflexis (infliximab-abda), a biosimilar to Remicade (infliximab), making it the fourth biosimilar approved to treat inflammatory types of arthritis.
Renflexis is the second approved biosimilar to Remicade. The first one, Inflectra (infliximab-dyyb), was approved in April 2016. This is the first time the FDA has approved two biosimilars for one original, “reference” medication.
Renflexis, manufactured by Samsung Bioepis, is a TNF (tumor necrosis factor) inhibitor, also called an anti-TNF, and is given by intravenous infusion. It is approved to treat the same conditions as Remicade – rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, plaque psoriasis, ulcerative colitis and adult and pediatric Crohn’s disease. Renflexis also carries the same risks and warnings as Remicade, such as a higher risk of serious infections.
“I think it is very big news with the potential for both good and bad impact,” says Anne R. Bass, MD, a rheumatologist at Hospital for Special Surgery in New York City. “The potential for good is cost savings. Biologics like infliximab have revolutionized the care of arthritis, but they are extraordinarily expensive – around $50,000 a year. If we can get the same benefit with a lower cost, that will be good for everyone, but it is not clear they will be priced significantly lower. I have heard 10 or 15 percent lower as opposed to more than that.”
The Affordable Care Act, signed in March 2010, created a special, abbreviated pathway to approval for biosimilars — products the FDA defines as “highly similar” to the original, approved biologic drugs – in this case, infliximab, the “reference” product. In order to get FDA approval, biosimilar manufacturers must show there are “no clinically meaningful differences” in terms of safety and effectiveness between biosimilars and their reference products. Only minor differences in clinically inactive components are allowed.
But many doctors and patients are concerned about the definition of “highly similar” and how that might affect their reaction to the medication. “Biosimilars won’t be identical in the way a generic is identical to a pill,” Dr. Bass says. “They will be similar, but the concern is they may not be similar enough, and that could potentially lead to unanticipated side effects or their not being as effective.”
Dr. Bass notes it’s also important from a monitoring standpoint that a patient not be switched to a biosimilar by a pharmacy or insurance company without both the doctor and patient being told first. She also believes that biosimilar manufacturers should be required to study patients receiving them to make sure they are safe and effective. Studies on safety and effectiveness have already been conducted in countries in Europe and Asia, where biosimilars have been on the market for a few years.
Renflexis will be marketed and distributed in the U.S. by Merck. A spokesperson for that company says it will be available in October, six months after the FDA approval date.
Jennifer Davis for the Arthritis Foundation
- What You Should Know About Biosimilars
- Arthritis Foundation Legislative Position on Biosimilar Substitution