The FDA's statement to HGEN says it all: "In it
Post# of 148158
"In its letter, FDA stated that it was unable to conclude that the known and potential benefits of lenzilumab outweigh the known and potential risks of its use as a treatment for COVID-19."
What's unclear? HGEN's treatment has known risks that the FDA doesn't like. Leronlimab, does not. Not rocket science.