My assumptions kick out earnings of just shy of half of that, or around $3.7bn, which would be about $9 per share fully diluted. Keep in mind that margins for a big BP bolting this on would be better than AMRN GIA margins.
I don't think you can value AMRN on P/E multiples though. At the moment they have a single drug with a defined lifetime. If they had an actual viable pipeline it would be very different.
I'm really feeling $50 to $60 PPS is the kill zone here.