The aflibercept biosimilar Pavblu has been marketed by Amgen since October 2024, after a District Court denied Regeneron’s motion for a preliminary injunction against the biosimilar maker. A Court of Appeals decided last week that Regeneron’s patent violation argument was not persuasive, validating Amgen’s decision to launch Pavblu at-risk.
Amgen’s at-risk launch of Pavblu yielded a significant first-entry advantage in this $6 billion-plus competitive market. None of the other four FDA-approved products have announced US launch dates, owing to ongoing patent litigation. If the history of biosimilar uptake for products reimbursed under buy-and-bill is any indication, Amgen should report impressive first-quarter 2025 earnings for Pavblu next month.
Amgen’s patent litigation success seems to be focused on the reference product’s formulation need for a buffer agent, in addition to aflibercept. When Amgen reengineered the production of aflibercept, it found a way to do so without the need for a buffer agent. The Appellate Court determined that the original District Court decision was correct, in that Amgen’s formulation without the buffer did not violate Regeneron’s patent, including the buffer agent. Therefore, enforcing an injunction against Amgen would have been erroneous. In contrast, the other aflibercept biosimilar manufacturers have incorporated buffers into their formulations and thus may still be subject to patent dispute.
However, Amgen’s at-risk launch and its court victory is likely to compel Regeneron to settle with the other manufacturers sooner than later, especially if Amgen makes rapid inroads into the aflibercept market.
The effect of the recently reported pause in Cimerli’s availability could also drive more volume towards an aflibercept biosimilar (rather than another ranibizumab product). It is unknown whether the interruption in Formycon’s ranibizumab biosimilar availability will last for a significant period.
