Table 1.

Comparison of EPO titers.

Reference	Culture characteristics	Max EPO titer
Restelli V et al.50	Suspension serum free CHO-K1 2.4 L stirred tank culture Culture length: 7 day	2400 U/mL (or 16* mg/L)
Sun et al.51	Suspension serum free HEK 293 EBNA1 cells cultured in equal volumes of 293 SFM II medium and a 5 × amino acid solution prepared based on DMEM/F12 medium formula Culture length: 10–12 days	4700 U/mL (or 33.6 mg/L)
Wang Z et al.52	MTX amplified adherent CHO in 12-well plate in IMDM +10% dFBS for 3 days, followed by SFM Culture length: 6 days	8000 U/mL (or 53* mg/L)
Park JH et al.53	Suspension serum free CHO spinner flask culture Culture length: 6 days	7000 U/mL (or 47* mg/L)
Our results	Suspension serum free HEK293-GS-KO EPO 2 L stirred tank culture supplemented with hydrolysate Culture length: 10 days	92 700 U/mL (or 696 mg/L)

*Estimated conversion based on 150 U/µg, as per the 3rd International Standard by the National Institute for Biological Standards and Control (NIBSC code: 11/170).