I can’t provide an “official” answer but I believe it’s likely...

I can’t provide an “official” answer but I believe it’s likely to be because of the stage it’s at. IMU have given poster presentations for HER-Vaxx at one or two conferences in the past few years and they now have an oral presentation lined up; which I presume is due to having phase 2 results and therefore having lots of real world data to talk about.
Until the drug is proven in patients it’s just a theory so gets as much prominence as all the other abstracts at the same stage. Others have mentioned on here poster presentations are still prestigious and having an abstract accepted and being allowed to present the poster is solid recognition it’s headed in the right direction.