New Pancreatic Cancer Treatment Activates Immune System
In Early Study, Strategy Shrank Tumors in Some Patients
Pancreatic Cancer Treatment: Study Details continued...
The antibody infusion, given once a month, was added to the routine gemcitabine treatment.
"They could keep receiving it until the tumor progressed or toxicity developed," Vonderheide tells WebMD.
The new treatment was found to be well tolerated in this phase 1 trial, Vonderheide says. Side effects included chills and fevers and usually went away within 24 hours.
After two cycles, the patients were scanned to evaluate the tumors. "We are reporting that five patients who received the antibody went on to tumor regression that was at least 30% or more," he says. That 30% is considered the cutoff for an acceptable response, he says.
To put the results in perspective, Vonderheide says that ''the response rate for gemcitabine alone is 5%, one out of 20. In a study this size [with the 21 patients] we would have expected one to have a response."
The median time for progression-free survival was 5.6 months (half longer, half less). The median overall survival time was 7.4 months.
In comparison, gemcitabine alone produces a median progression-free survival of 2.3 months and a median overall survival time of 5.7 months.
One surprise: the researchers thought the antibody treatment would activate white blood cells known as T cells to attack the tumor. But the treatment actually turned on another kind of white blood cells called macrophages.
The study was funded by the Abramson Family Cancer Research Institute, the National Cancer Institute and Pfizer Corp., which makes the antibody.