Primary completion date should be the date after which formal analysis will occur.
Study completion date is when the last follow-up will occur, i.e., 6 months after. I remember Dr. Sweeney said that also in his interview that patients will be followed up at / after 6 months. This follow-up is usually safety follow-up, meaning they're going to check if the patients expereiced any untoward adverse events.
I really hope that the company has a plan for long-COVID trial. This wish is obviously profit driven. But, these patients are really suffering and their daily lives are seriously affected by long-COVID. If the effective treatment is available, i.e., RVX hopefully, and clinical trial data can prove that, these patients don't have to suffer with no treatment.