ASCO: Radioimmunotherapy + gemcitabine shows promise for pancreatic cancer
The results of an ongoing phase I/II study for treating advanced pancreatic cancer with a combination therapy of Immunomedics' antibody, clivatuzumab tetraxetan, (90Y-hPAM4) and anticancer drug gemcitabine, which demonstrated therapeutic activity at two 90Y dose levels with minimal hematologic toxicity was presented with positive findings at the seventh annual Gastrointestinal Cancers Symposium in Orlando, Fla. this week.

The study included patients with previously untreated, locally advanced or metastatic, pancreatic cancer who were treated in four-week cycles (gemcitabine once-weekly; 111In-hPAM4 in the first week for imaging, biodistribution and dosimetry; 90Y-hPAM4 once-weekly the last three weeks), which was repeated in the absence of progression or unacceptable toxicity.

Kenneth Pennington, MD, at Center for Cancer Care at Goshen Health System in Goshen, Ind., and colleagues, assessed the tumor responses by CT, FDG-PET imaging and by a biomarker, CA19-9 serum levels.

Pennington reported that among the 27 patients enrolled, 22 patients were evaluable and 68 percent of these evaluable patients showed evidence of tumor shrinkage or stable disease, with one-third of these being assessed by CT as partial responses.

In addition, after the first cycle, 47 percent of patients showed improvement by PET imaging studies (more than a 25 percent decrease in the tumor’s metabolic uptake) and 38 percent of patients had more than 50 percent decrease in CA19-9 levels.  

The study also showed that higher doses of the radioactive antibody, 90Y-hPAM4 could increase the overall response rate, since patients given 12 mCi/m2 weekly for three weeks showed better results than those given lower doses (73 vs. 57 percent, overall response rate).