How were you able to acquire a PhD without a publication?
When written in a single sentence, it implies that you have never written a publication, post- or pre- or during- a PhD.
I will rephrase my question: have you, or have you not, written a publication?
> My work is trade secret so I’ve never filed a patent, written a publication, nor given a talk.
"My work is a trade secret so..." is an important part of the sentence, which I read as a qualifier/context to the "never".
It could be interpreted either way.