I think NWBO MUST disclose material (and safety/early efficacy Direct results are definitively material) information with a PR.
Be it today or on June 1st before poster presentation Reg FD impose that all publicly traded company must disclose material information to all investors at the same time. Having this information disclosed just (or first) to ASCO attendees would definitively not be in compliance. Moreover waiting for the last minute before June 1st, would definitively cause a leak of information due to the stand preparation, several people would become aware of its content before the others.
If I were LP, I would PR the relevant information asap (or at latest June 1st before market open), and then delve into the scientific details during the presentation for the benefit of the scientific community/attendeees.
By not doing so, she would expose the company to potential lawsuits/litigation
I would be very #$%$ off if there wasn't a PR. Unless of course they do not disclose anything outside of the abstract which I don't think they are allowed to do in a P-1.. Either way, anything regarding efficacy would have to be in a PR prior. I would riot if it was not!!