Archigen Biotech Ltd., a 50-50 joint venture between Samsung BioLogics and UK-based AstraZeneca, has initiated the clinical trials for a new Rituxan biosimilar in South Korea, Samsung BioLogics said Tuesday.

According to the Korean Ministry of Food and Drug Safety, Archigen’s SAIT101 was granted approval to begin phase 1 and phase 3 clinical trials at eight local hospitals on Nov. 11. The trials in Korea are currently ongoing, the Samsung unit said.

Biosimilars refer to cheaper, near-replicas of biologic drugs which have lost patent protection. SAIT101 is a biosimilar referencing Rituxan, a lymphatic cancer treatment which generated $7.3 billion in annual sales last year as the world’s second best-selling biologic drug.

Unlike newly developed drugs which are required to complete phase 1, 2 and 3 clinical trials before they can be submitted for approval, biosimilars are generally mandated to undergo only phase 1 and phase 3 trials.

Phase 1 clinical trials are designed to demonstrate pharmacokinetic similarity between the biosimilar and the originator drug, while phase 3 trials aims to prove that the two drugs display equal efficacy and safety.

In addition to Korea, Archigen Biotech has been conducting clinical trials of SAIT101 in the US since July, according to Samsung BioLogics.

Once the drug gains regulatory approval by the US Food and Drug Administration, AstraZeneca is set to take charge of SAIT101’s marketing and sales in the US, it added.

In addition to Archigen, Samsung BioLogics owns another biosimilars development unit -- Samsung Bioepis. Bioepis currently has currently six biosimilars under development, two of which have been commercialized in Europe.

Meanwhile, a number of other global companies, most notably Celltrion, have been quickly moving to develop and bring to market their own Rituxan biosimilars.

Last week, Celltrion’s Truxima scored sales approval in Korea for the treatment of Non-Hodgkin’s lymphoma, chronic lymphocytic leukemia and rheumatoid arthritis.

Celltrion already submitted Truxima, also known as CT-P10, to the European Medicines Agency for approval in October 2015. It expects to begin selling the drug in Europe upon the drug’s expected approval in 2017.

The company also plans to file Truxima for review by the US FDA by early next year, with aims to become the first company to introduce a Rituxan biosimilar in the US.

In addition, Novartis-owned Sandoz submitted its own Rituxan biosimilar to the EMA for approval in May this year. Pfizer and Amgen are wrapping up third-phase clinical trials of their own Rituxan biosimilars as well.

By Sohn Ji-young (jys@heraldcorp.com)