Century City-based Ritter Pharmaceuticals was this week’s biggest mover, gaining 17 percent to end at $1.74. Westwood-based Puma Biotechnology was also among the week’s movers. The drug company gained 15 percent to end at $68.08. Culver City’s immunotherapy company NantKwest was the week’s biggest loser, dropping 14 percent to end at $7.91.