In your link they have only done tests on rabbits.
In this post they have already done some tests on humans and are now increasing the dosage since March.
> Small-scale studies began in 2022. Three groups of four healthy male volunteers aged 20 to 50 received a single intravenous injection of hemoglobin vesicles — artificial oxygen carriers that mimic the structure of red blood cells — in increasing amounts, up to 100 milliliters. While some participants experienced mild side effects, there were no significant changes in vital signs, including blood pressure. Building on that success, Sakai announced that his team was accelerating the process last July. In March, it started administering between 100 and 400 milliliters of the artificial blood cell solution to volunteers.
> If no side effects are confirmed, the trial will shift to examining the treatment’s efficacy and safety. It aims to put the artificial red blood cells into practical use by around 2030.
So what's different this time?
(Upon further examination, the 2019 team at the National Defense Medical College also had Dr Hiromi Sakai. So why is this news now?)