Archigen Closes Its Doors After Failing to Introduce Rituximab Biosimilar

Samsung Biologics announced in its third quarter earnings report that they and partner Astra Zeneca have agreed to shut down their joint venture Archigen Biotech. This news was first reported in the Korea Biomedical Review.

Archigen was created in 2014 with the hope of developing a biosimilar to reference product Rituxan/MabThera for the treatment of follicular lymphoma. We profiled Archigen in 2018, and tried to update their clinical trial outcomes in May 2020, but did not receive a response. The handwriting may have been on the wall then.   

Its phase 3 trial of SAIT101 was completed in October 2020, and results can be viewed on This investigation of 316 patients with low-burden follicular lymphoma revealed week 28 overall response rates of 66.3% vs. 70.6% for the biosimilar and reference products, but a week 4 overall response rate of 59.6% and 70.0%, respectively. Complete response rates were equivalent at week 12 and 28 (25.0%–26.9% and 34.7%–35.2%, respectively). Partial response rates at week 12 were different, at 33.1% for SAIT101 and 45.9% for the reference product but similar at week 28 (32.4%–36.8%). P values were not provided for any of these differences.

In terms of immunogenicity, the appearance of antidrug antibodies did not appear to be different between the treatment groups over time. The incidence of neutropenia was higher in the biosimilar group (4.5% vs. 0.63%), infusion-related reactions were lower in the biosimilar group (11.5% vs. 16.5%), and headache was more common in those taking SAIT101 (5.7% vs. 1.3%). There appeared to be no other differences between the treatment groups.

It may be worth noting that Biogen is a partner with Roche in the manufacture of Rituxan. Biogen is also a 50% partner with Samsung Biologics in its Samsung Bioepis subsidiary (as well as a US marketing partner with Samsung Bioepis on its ophthalmologic biosimilars). This tangled web may have had something to do with the decision to stop work on SAIT101 and close down Archigen.

Pfizer’s Ruxience® began marketing in January of this year for the treatment of follicular lymphoma, and according to Bernstein Research, had captured more than 20% of the market after only 9 months.

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