FDA Approves Infliximab Biosimilar for Subcutaneous Use Save

Another infliximab biosimilar has been FDA approved, but this new version of Inflectra can be given subcutaneously for patients with inflammatory bowel disease.

The Celltrion drug, Zymfentra (infliximab-dyyb), is approved for maintenance therapy in adults with moderately to severely active Ulcerative colitis and Crohn's disease after induction therapy with IV infliximab.

Approval of this subcutaneously administered infliximab biosimilar does not apply to and is not intended for use in patients with RA, PsA, SpA, PsO, polyarticular JIA, etc.

Infliximab-dyyb, developed as CT-P13, was FDA approved in 2016 as an IV product, marketed as Inflectra, and approved for all the same indications as infliximab or Remicaded (RA, PsA, PSO, IBD, polyarticular JIA, etc.).

Several years ago, Celltrion also developed a subcutaneous (SC) formulation of Inflectra for international use, where it is often labeled as Remsima-SC, an infliximab biosimilar. 

The "351k" expedited pathway for biosimilar development stipulates that the approved biosimilar would be delivered in the same manner (intravenous), for the same indications, as the reference product.  Hence, for Celltrion to have a different delivery method (subcutaneous) of their approved infliximab biosimilar, they would have to pursue drug approval via the traditional "351a" pathway that would require multiple phase 3 trials to demonstrate efficacy and safety. 

The new subcutaneous formulation of CT-P13 (a TNF alpha inhibitor) was approved based on two phase 3 pivotal trials infliximab-dyyb as maintenance therapy in patients with moderately to severely active UC (LIBERTY-UC) and CD (LIBERTY-CD). In both of these 54-week trials, infliximab-dyyb demonstrated superiority to placebo in the primary endpoints of clinical remission (UC and CD) and endoscopic response (CD) when given as maintenance therapy after induction therapy with IV infliximab.

No new safety signals or concerns were seen in these trials. The most common adverse events were COVID-19, anemia, arthralgia, injection site reaction, increased alanine aminotransferase, and abdominal pain.

Zymfentra—also marketed as Remsima SC in some international markets (European Union, Brazil, Republic of Korea). The approval comes about 9 months after Celltrion submitted the biologics license application (BLA) for the product in December 2022.

Zymfentra will have patent protections for its dosage form until 2037 and route of administration until 2040, according to Celltrion.