On October 15, 2021, the U.S. Food and Drug Administration (“FDA”) approved Boehringer Ingelheim’s Cyltezo® (adalimumab-adbm), the first interchangeable biosimilar to AbbVie’s blockbuster immunosuppressant Humira® (adalimumab).  We previously discussed Boehringer Ingelheim’s Citizen Petition requesting a change in the FDA’s interpretation of “strength” of biological products under the Biologics Price Competition and Innovation Act (“BPCIA”).  The approval of Cyltezo® before a decision on the Citizen Petition was a surprising development.  This marks the second interchangeable biosimilar product approved by the FDA after Semglee® (insulin glargine-yfgn), but is importantly the first interchangeable monoclonal antibody to be approved.

In order for a biosimilar to acquire the “interchangeable” designation, in addition to meeting the requirements for a biosimilar (i.e., highly similar to, and no clinically meaningful differences from, an approved reference product), the manufacturer must show that the interchangeable biosimilar product is expected to produce the same clinical result as the reference product in any given patient. For biological products administered more than once to an individual patient, the manufacturer needs to further provide data ensuring that the risk in terms of alternating or switching between use of the interchangeable biological product and its reference product is not greater than the risk of using the reference product without switching.

The benefit of meeting these more extensive requirements is that, just like with a traditional generic drug, an “interchangeable” biosimilar can be substituted for the often pricier reference product by a pharmacist without the prescribing doctor’s intervention or approval (subject to state pharmacy laws).

Cyltezo®, which is one of several adalimumab biosimilars in the United States, was originally approved as a biosimilar to Humira® in August 2017. As we previously reported in this post, Humira® is the world’s most profitable drug, with sales of $20 billion in 2020, over $16 billion of which was U.S. sales revenue. While multiple companies have launched adalimumab biosimilars worldwide, none has launched in the U.S. due to settlements of patent litigations delaying launch until 2023, including Cyltezo®’s planned launch in July 2023.

If the 30 percent drop in sales of Humira® upon the initial launch of adalimumab biosimilar products in Europe is any indication, AbbVie is likely looking at a significant decline in its U.S. market share upon launch of the U.S. adalimumab biosimilars. The availability of an interchangeable version has significant implications for other biosimilar makers. For example, Cyltezo’s “interchangeable” designation will give it a competitive edge over other adalimumab biosimilars because the manufacturer of the interchangeable biosimilar has already proven the safety and efficacy of the cheaper “pharmacy-level substitution,” even in the middle of a course of treatment using the reference product.  Pharmacy benefit managers will likely prefer the interchangeable drug over all others, and place it on their preferred formularies to achieve cost savings and convenient switching of patients.

Depending on Cyltezo®’s level of success, the U.S. landscape for future biosimilar development may transform in at least following ways:

  1. races to obtain interchangeable designations for other biologics becoming the norm;
  2. new strategies and efforts by brand manufacturers to thwart approval of interchangeable products;
  3. changes in how brand manufacturers market their products after approval of an interchangeable given the ease and automation of substitution with an interchangeable at the pharmacy level;
  4. relegation of non-interchangeable biosimilars to racing to the bottom on price; and
  5. a need for newly developed biologics to demonstrate safety and/or efficacy advantages over existing biologics that treat the same indications to convince doctors or pharmacy benefit managers to switch patients to the new, higher priced biologics over the existing approved interchangeable products.

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