Uh, where have you read that a company does not require a shareholder meeting annually? Unless its a LLC which NWBO is not one.
List out the past 7 years of ASM and you would see in 2015-2016 they were in december, and only 2017's was late and held in January. From there its been more in the midyear ASM but we have till the end of the year to hold any meeting.