It doesn't. Did _you_ read the article?

> an experimental medicine combined with Atezolizumab, an immunotherapy drug.

Atezolizumab is not the experimental drug, it's an already approved drug. The drug in question is the unnamed drug it was combined with.

Huh. It was there earlier. I can't remember what it said, a something-mab, so monoclonal antibody. I wonder why the BBC did a wee ninja-edit? Legal reasons?

Yes.

> experimental medicine combined with Atezolizumab, an immunotherapy drug

Atezolizumab is an approved anti-PD-L1 monoclonal antibody. What’s the experimental medicine?

Seems to have been ninja-edited. It was there earlier.