More importantly: PD-1 is NOT FDA approved as was CTLA-4.
That means PPHM could not do any pre-clinical or clinical trial with PD-1 without the authorisation of the BP that owns it (Merck I think or was it Roche).
That means they've talked about it!
Peregrine Pharmaceuticals the Microsoft of Biotechnology! All In My Opinion. I am not advising anything, nor accusing anyone.