My wife's recurrence was treated with 8 GAC treatments then 10 more GA treatments. The CA19-9 bottomed out after the 6th GAC treatments but started rising despite "staying the course" with more treatments. We were ready to quit treatments because the side effects are so debilitating and our requests to go back on folfirinox were being rejected. Finally, we got the approval to switch to Onivyde (same as folfirinox but with the liposomal modified irinotican). After 2 Onivyde treatments, her CA19-9 has dropped 59%! We won't get another scan until after the 6th treatment but now have renewed hope that the cancer can be beaten. Our oncologist is also reviewing clinical research for additional agents for treatment and eventual maintenance. CA19-9 is only one data point but has been very good at predicting recurrence or absence of tumors for my wife.