FDA approves Herceptin biosimilar as US patent expires

The FDA has approved Amgen and Allergan’s biosimilar of Roche’s Herceptin, just in time for the breast cancer blockbuster’s patent expiry.

Herceptin’s main US patent expires this month, paving the way for cut-price competition in the US at last.

Herceptin’s US sales were just over $2.9 billion last year, and globally they were nearly $6.8 billion, and it has been off-patent in Europe since 2014.

Amgen and Allergan will also compete against two other manufacturers to grab market share from Roche.

Mylan and Biocon got their Herceptin biosimilar approved by the FDA in December 2017, followed by Samsung Bioepis early this year.

There was no word from Amgen and Allergan about when they plan to launch the biosimilar or their pricing strategy, and in the US manufacturers of branded drugs have become adept at constructing patent defences to prevent competition.

The latest Herceptin biosimilar is branded as Kanjinti (trastuzumab-anns) and is approved in all indications of the reference product.

These are for the treatment of HER2-overexpressing adjuvant and metastatic breast cancer and HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma.

Biosimilars are tested rigorously to ensure that they are as safe and effective as the original drug.

But as they are biologic drugs manufactured in cells there may be some slight differences compared with the reference product.

The FDA approved Kanjinti after it was proven to be highly similar to and have no clinically meaningful differences from Herceptin.

This was based on extensive comparative analytical, pharmacokinetic and clinical data.

Amgen and Allergan noted that unlike the other biosimilar rivals they have data testing a switch from Herceptin to the biosimilar, showing that after a single transition Kanjinti showed similar safety and immunogenicity in patients who were previously on Roche’s drug.

This is the second biosimilar approved in the US from Amgen and Allergan’s partnership, which has already got a biosimilar to Roche’s Avastin (bevacizumab) cancer drug backed by the FDA.

Amgen already has a biosimilar of AbbVie’s Humira (adalimumab) approved in the US, but like several other manufacturers cannot launch until 2023 when the drug’s legal defences finally expire.