How Much Does Provider Comfort With Biosimilar Prescribing Matter?

They love me, they love me not, they love me, they love me not…

For several years, we’ve been reading surveys or hearing anecdotal reports that certain specialists are more willing than others to prescribe various biosimilars. For instance, it is widely accepted that oncologists have less resistance to biosimilar prescription than say gastroenterologists (GIs).

There may be some rationale to this perception. Oncologists have had longer exposure to biosimilars, with the introduction of filgrastim in 2015. In comparison, the first infliximab biosimilar was launched in 2016. The biosimilar effect may have even predated 2015, with the launch in 2012 of the follow-on filgrastim biologic (Granix®). Oncologists had the opportunity to become comfortable with a biosimilar precursor that produced the same outcomes as the Neupogen® reference product, three years before the launch of Zarxio®. This may have alleviated any unease with oncology biosimilar prescribing down the road, leading to the widespread use of bevacizumab, trastuzumab, and rituximab biosimilars, which quickly dominated marketshare in their respective drug categories.

On the GI side of the fence, their infliximab prescribing in the US was stunted by poor payer coverage, partly due to Janssen’s rebating of the reference product Remicade® and Pfizer’s inadequate response. However, infliximab biosimilar prescribing has increased over the years, leading into the current adalimumab launches in 2023. Savings are going to accrue quickly with biosimilar competition for Humira®’s business. But will gastroenterologists prescribe it?

It depends a bit on who you ask. A new survey from Cardinal Health reports that in the autoimmune category, GIs had fewer biosimilar concerns than dermatologists or rheumatologists: 50% of the 72 GIs surveyed indicated that they were comfortable prescribing an adalimumab biosimilar to their patients, and another 43% were “somewhat comfortable.” Only 7% indicated any unease. Of the 126 dermatologists surveyed, 31% were very comfortable, 44% were somewhat comfortable, and 25% had at least some reservations. Rheumatologists’ attitudes split the difference: 37% (of 103 surveyed) were very comfortable, 49% somewhat comfortable, and 15% were less comfortable with prescribing biosimilars.

Since the introduction of the biosimilar approval pathway, the watchword for physician acceptance has been education, not necessarily experience in prescribing. I believe that we assumed that with experience, physicians would become educated about the nuances of biosimilars. Another report from Northwestern University refutes this. In that published post, oncologists—the group with the most biosimilar experience—didn’t correctly answer questions about biosimilars. This was despite the fact that 88% of the sample treated their patients with biosimilars and 63% indicated that biosimilar prescribing was mandatory at their practice site. For instance, only 52% knew that biosimilars were not the same as generic medications. One third answered that biosimilars had the same chemical structure and manufacturing as the reference product, and only half understood the purpose of interchangeability. One third stated that their use of biosimilars was limited by concerns about efficacy. Of course, this last assertion directly opposes the point of a biosimilar—an inexact copy of a biologic that results in equivalent clinical efficacy and safety. (One caveat—these data were obtained in 2020, a long time ago in biosimilar terms.)

And yet oncologists prescribe them in droves. Whether because of financial incentives (e.g., Oncology Care Model participation), payer coverage restrictions, or other reasons, they prescribe biosimilars, even though they don’t seem to be completely comfortable with them or understand them.

In other words, maybe with some base level of education attained, biosimilar uptake is then more dependent on factors unrelated to prescriber comfort or choice. This may be even more evident in a non–buy and bill category like adalimumab and ustekinumab.

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