All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no Islamic impediment for attending this forum, eating food, and accepting gifts, as there is no evil to be feared from such a forum. This is not similar to direct gifts from the pharmaceutical company to the doctor in order to favor it and prescribe its medicines to patients; this is what is prohibited as a way of blocking all the means that lead to what is forbidden.
For more benefit on doctors taking promotional gifts from pharmaceutical companies, please refer to Fataawa 115843, 403819, 99730 and 329050.
Allah knows best.