Armed with new Phase III data, Celltrion claims on course to be first-to-market with Rituxan biosim

Seoul, Korea

Celltrion has chalked up yet another success in its biosimilars development program. The South Korean company says its biosimilar version of Roche's ($RHHBY) Rituxan has cleared a Phase III trial showing it works as well as the originator drug in rheumatoid arthritis.

The new data add to the evidence supporting the biosimilar--called Truxima (CT-P10)--which is on course to become the first Rituxan biosimilar to reach the market after being filed in the EU last November.

At the time, the marketing application wrong-footed market observers who had predicted that Novartis' ($NVS) Sandoz unit would claim the first-to-file crown in developed markets, after Boehringer Ingelheim abandoned its own version after a review of its pipeline. 

Sandoz filed an EU application for its GP2013 candidate in May, while another player--Poland's Mabion S.A.--said in the summer that it expects to file its MabionCD20 version before the end of the year. However, Celltrion remains in pole position in Europe, where Roche's drug is sold as MabThera.

Roche has said it is expecting to face Rituxan biosimilars by the end of 2017 in Europe, and in the U.S. sometime after 2019. The EU is a much more developed market with the first biosimilar approved there more than a decade ago, while the first US approval came last year.

"We are expecting to reap 'first mover' advantages from being the first company to introduce a Rituxan biosimilar in the global market," said Celltrion in a statement reported by the Korea Herald. The company has said it plans to roll out the drug "as swiftly as possible."

There has been some debate about Celltrion's strategy for CT-P10, particularly after Pfizer opted to hand back rights to the drug along with its CT-P6 biosimilar of Roche's breast cancer treatment Herceptin a year ago. The Korean firm has however just inked an alliance with generics giant Teva for both those drugs in the U.S. and Canada.

Moreover, Celltrion is also reported to have filed initially for use of the drug in rheumatoid arthritis only, which accounts for a small proportion of Rituxan's global sales of $7.39 billion in 2015. 

Upwards of 90% of the drug's sales are thought to come from cancer indications such as non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL), so if Celltrion is relying on a staggered application it could be some time before it has a green light across the indications approved for Roche's drug.

Added to that, Celltrion's marketing application is for an intravenous formulation of rituximab, while Roche has been steadily transferring patients over to a newer subcutaneous version of Rituxan that started rolling out in 2014.

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