This weight gain/loss thing is very interesting...I'm going to get in touch with Genentech to see what their official word is.I lost weight while I was on chemo/Herceptin BUT since I've been NED(yeah!!)& on herceptin alone,I've gradually gained 8 lbs in 6 mos, with virtually nothing changing in my diet, exercise, etc!It's been baffling me...maybe this is the answer.I'll share whatever info I find!