Background: Mesenchymal stem cells are known to have immunomodulatory properties and may potentially have therapeutic effect in lupus nephritis. Mesenchymal stem cells form a haploidentical donor are an attractive cell source

Objectives: CS20AT04, a haploidentical allogeneic bone marrow-derived mesenchymal stem cell, was evaluated in patients with lupus nephritis for safety and tolerability.

Methods: This was a single-arm phase 1 dose-escalation trial of CS20AT04 in adult patients with lupus nephritis (NCT03174587). A 3 + 3 design was used for dose escalation. The starting dose was 2.0 x 106 cells/kg and was escalated to 3.0 x 106 cells/kg if there no dose-limiting toxicity. The primary objective was to determine the maximum tolerated dose and evaluate the safety and tolerability at 28 days after the infusion.

Results: Seven patients were enrolled in the study. Patients received CS20AT04 through intravenous infusion. The initial dose of 2.0 x 106 cells/kg was administered for the first 3 patients without any dose limiting toxicity. There was 1 patient who were not administered the full 2.0 x 106 cells/kg dose due to technical error during infusion. The patient did not show dose limiting toxicity, but 1 additional patient was enrolled to have 3 patients who received the full 2.0 x 106 cells/kg dose before escalating to the next level dose. The dose of 3.0 x 106 cells/kg was administered for the next 3 patients without any dose limiting toxicity. Three adverse events were reported (1 diarrhea, 1 toothache, and 1 arthralgia) and they were all NCI-CTC grade I events.

Conclusion: CS20AT04 was well tolerated in single dose up to 3.0 x 106 cells/kg in patients with lupus nephritis.

Acknowledgments: This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI15C0778).

Disclosure of Interests: Chan-Bum Choi: None declared, Tae Yong Lee Shareholder of: Corestem Inc, Employee of: Corestem Inc, Kyung Suk Kim Shareholder of: Corestem Inc, Employee of: Corestem Inc, Sang-Cheol Bae: None declared