Report: Don't count Celltrion out of Rituxan biosim race

Celltrion prematurely ended a Phase III trial for a biosimilar version of Roche's ($RHHBY) big seller Rituxan, but the South Korea-based biotech has plans to revive late-stage development of its copycat candidate in the second half of 2013, BioPharm Insight reported.

Rituxan/MabThera, a therapeutic for rheumatoid arthritis and blood cancers, has been one of the most sought targets of biosimilars players for years. The biologic brought in global sales of $7 billion last year for Roche and its partner Biogen Idec ($BIIB), and exclusivity on the therapy is expected to expire first in Europe and then in the U.S. When Bloomberg reported this week that Celltrion halted a late-stage study of its biosim, there were echoes of the canceled trials from Samsung Electronics and Teva Pharmaceutical.

However, Celltrion appears to be a unique case. As the news service reported, the biotech has altered its Phase III plans based on guidance from regulators. A company spokesperson told the publication that the company had planned to begin the Phase III study in cancer patients before the end of an ongoing Phase I study of its rituximab biosim, CT-P10, in RA patients. And the Phase III was canceled because the company has changed its plans and now aims to begin late-stage development of CT-P10 after the end of the Phase I trial later this year.

Clearly, the state of regulatory flux for biosimilars puts developers on shaky ground. In the U.S., the industry has been waiting for clear direction on what exactly will be required to qualify biosimilars as equivalent to the originals. Though Celltrion appears to be delaying the start of late-stage trials for its biosim version of Rituxan, BioPharm reports that the company should be considered in third place in the race to advance the copycat versions behind programs from Novartis' Sandoz and Boehringer Ingelheim, both of which have already begun Phase III studies.

In the meantime, RBC Capital Markets issued a clarification today of its note to investors earlier this week that said Hospira ($HSP) was collaborating with Celltrion on the Rituxan biosimilar, saying that Hospira had not confirmed that CT-P10 was included in the broad biosim partnership between the two companies. Yet RBC still believes that CT-P10 is part of the two companies' collaboration.

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