The costs of trying to turn a novel therapeutic approach into a real therapy are extremely high - hundreds of millions of dollars. I'm unaware of any approved therapy that utilizes protein transduction of cells - I also suspect existing protein transduction methods aren't very efficient. There is a tiny pile of evidence that this method "works" in vitro in cultured cell models of infection, I can imagine a hundred ways it will fail in bodies.
There's a reason some ideas are left unexplored by industry.