FDA Rejects Celltrion's Rituximab and Trastuzumab Biosimilars

Today, Celltrion announced that the FDA has issued Complete Response Letters (CRLs) for 2 of its products, CT-P10, a proposed rituximab biosimilar referencing Rituxan, and CT-P6, a proposed trastuzumab biosimilar referencing Herceptin.

According to a statement on Celltrion’s website, the FDA has requested supplementary information about the products. Celltrion says that it will work closely with regulators to address the issues that led to the CRLs, and that it expects to receive FDA approval of both drugs within the year.

US regulatory rejection of the 2 products does not come entirely as a surprise; the Republic of Korea drug maker received the FDA’s Form 483 last year, noting 12 observations related to a range of issues, including incomplete records, inappropriately designed equipment, deficient environmental monitoring, and inadequate validation of sterilization processes. Then, in February 2018, Celltrion received a warning letter from the agency related to its manufacturing processes. While Celltrion assured investors that it was making progress to address the concerns in a timely fashion, Celltrion’s partner Teva said that remediation of the manufacturing facility’s issues would likely result in a “delayed approval” of the drugs.

Despite these manufacturing issues at the Celltrion facility, CT-P6 recently gained an EU marketing authorization, and Celltrion plans to launch the product in Europe under the name Herzuma.

CT-P10 is also approved in the European Union, where the treatment is marketed under the brand names Blitzima, Ritemvia, Rituzena, and Truxima. Introduction of the partnership’s biosimilar (as well as Sandoz’s competing biosimilar product, Riximyo) in the European Union has begun to have a substantial impact on the market for rituximab; Roche said in its 2017 annual report to investors that European sales of innovator rituximab dropped by 11% because of competition from biosimilar challengers.