Amgen, Pfizer Now Seeking Adalimumab Interchangeability, but…

The earnings reporting season is upon us, and with that comes news about fiscal and nonfiscal progress for individual biosimilar manufacturers. Some news about Amgen’s and Pfizer’s adalimumab biosimilars caught my attention.

Amgen’s Interchangeability Play

At its third-quarter conference, Amgen announced that it is enrolling patients in a multiple-switching trial in an effort to obtain the interchangeability designation for Amjevita®.

Amgen’s phase 3 study began in early October and is scheduled to be completed in April 2023. Amgen will recruit over 400 people with plaque psoriasis to participate in the trial, Assuming the manufacturer files a supplemental BLA for interchangeability after completion of the trial, this implies that Amjevita will be marketed for approximately one year before receiving the FDA’s decision.

Amgen is currently considered to be the first adalimumab biosimilar in line to launch, in January 2023 (this does not consider the potential for an earlier launch by Alvotech or Celltrion, who have not yet announced agreements with AbbVie). Boehringer Ingelheim currently has the only FDA-designated interchangeable adalimumab, but it is not scheduled to launch until early summer 2023.

Pfizer’s Interchangeability Application

An effort that may result in more immediate results, Pfizer also announced in its third-quarter earnings call that it is filing a supplementary BLA for Abrilada®—in December of this year. If approved according to schedule, that would certainly give Pfizer the designation well in advance of its own anticipated 2023 launch. That could seriously affect Boehringer’s prospects for garnering early marketshare, based solely on the interchangeability of the product.

As reported earlier, Alvotech is also seeking interchangeability approval for ATV-02. The timing of Alvotech’s approval and launch will further cloud this scenario. Any other entrants onto the interchangeability dance floor will further detract from the value of the designation over the longer term: It is critical to remember that interchangeability only applies between the respective product and the reference drug, not between other biosimilars or interchangeable biosimilars.

Interchangeability and Exclusivity

Here’s where things could be even more complicated (at least for me, anyway). According to the FDA 2019 guidance on biosimilars, Boehringer Ingelheim, in receiving the first interchangeability for an adalimumab biosimilar, should have at least 12 months exclusivity before the agency can designate another agent as interchangeable. Originally, I read this to be 12 months of exclusivity starting from the date of approval. In that case, Boehringer’s exclusivity would expire in October 2022, many months before it launched. A more careful reading of the guidance says that this time begins once the product is marketed. In that scenario, Boehringer would have sole exclusivity on the interchangeability designation until July 2024, more than 18 months after Pfizer might ordinarily be expected to receive FDA’s approval (perhaps a year after Abrilada launches) and shortly before Amgen might receive the designation.

However, there is another provision of the guidance that may apply here: Exclusivity would be given for 18 months after approval of the first interchangeable biosimilar biological product “if the applicant that submitted such application has not been sued under subsection (l)(6).” Wait a moment. What biosimilar maker hasn’t been sued by the reference maker?

I’m not an attorney, nor do I have any experience writing FDA regulations. Perhaps one of our readers can enlighten us as to which exclusivity clause applies here?

On a Related Note

Amgen also announced that its trial to test multiple switches of its ustekinumab biosimilar candidate ABP 654 is underway. According to the trial listing in, this study will be completed in March 2023, ahead of the patent expiration on the reference drug Stelara® (September 2023), and thus Amgen’s anticipated launch.

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